DPHY 5001

2. What are the functional problems associated with them?

Excess work for the heart with long-term adverse consequences Strokes and cerebral infarcts Kidney injury and failure

general chemical structure of local anesthetics consist of?

aromatic group, ester or amide group and amine group, with a few exception.

4. What determines the polarity of a wave form in an electrocardiogram?

arrangement of leads?

Transport blood under high pressure to tissues, and thus have strong vascular walls; blood flows at a high velocity in the arteries.

arteries

baroreceptors are stimulated by stretch in what?

arteriole wall *-BP receptors send nerve impulses to medulla to vasomotor center BP, and vise versa (maintain homeostasis).

effect of membrane electrical potential on diffusion of ions is described

as "Nernst Potential."

14. Describe the structure of the lymphatic capillaries.

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14. How does one calculate cardiac output in terms of heart rate and stroke volume? What happens to cardiac output as right atrial pressure increases?

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14. State, in qualitative terms, the extent of reabsorption of the volume of the glomerular filtrate from the proximal tubule and from the distal nephron.

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15. How does the right heart differ from the left heart structurally and functionally?

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16. What factors alter the mean electrical axis of the ventricle?

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17. Describe, in the proper chronologic order, the manner in which renin and angiotensin can blunt decreases in blood pressure.

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17. How can pulmonary edema occur?

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17. Name four substances which are actively transported by the renal tubular epithelium.

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19. How does the lung match gaseous ventilation with blood perfusion?

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2. What is functional hyperemia? What causes it?

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24. Name two substances whose renal plasma clearances are good estimators of renal plasma flow (RPF). State why their clearances are good estimators of RPF while those of sodium, potassium or chloride, for example, are not.

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25. State the normal adult renal plasma clearance values for: sodium; potassium; inulin; PAH; penicillin; glucose; fluoride.

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4. Describe how epinephrine and norepinephrine released from the adrenal medulla participate in emergency blood pressure regulation.

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6. Account for medullary interstitial hypertonicity in terms of the countercurrent multiplier system.

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6. Describe how each of the following affect temperature regulation, and how each would be treated clinically: dehydration exhaustion

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9. State why renal excretion data are less informative than renal plasma clearance data.

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A solution of 1 osmole solute in 1 kg water has an osmolality of 1 osmole per kg.

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The student will describe the mechanisms thought to be responsible for muscle fatigue.

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What is a sodium channel? Is it always open? Why not?

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What is an isotonic solution? Are all isosmotic solutions isotonic? Are any dental medicaments hypertonic?

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What would happen to the action potential if the extracellular sodium concentration fell from 145 to 110 mEq/L? What would be the functional consequences?

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When in the ECG is the heart relatively refractory?

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Why does it take so long to initiate and terminate smooth muscle contraction?

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t/f sympathetic plays more of a role in regulation of vascular function than parasympathetic

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Name the major neurotransmitters at each of the following d. parasympathetic neuroeffector junction.

ALWAYS Ach

caloric or energy equivalent of 1 gram of carbohydrates, proteins and fats and their relative contribution to our diet.

BO #1 Calories % of diet in US % in Mongolia -Carbs- 4Cal/gm 45% | 80% -Fat- 9Cal/gm 40% | 10% -Protein- 4Cal/gm 15% | 10% So, we could get by with a lot less fat and protein than we actually consume

undigested fat in duodenum causes secretion of _

CCK

Sinoatrial nodal block, with A-V nodal rhythm during the block period

Caused by sudden cessation of P waves, causing the ventricle to pick up, but with slow rate of QRS-T complex

role of cortisol

Cortisol enables an organism to withstand stress and also inhibits antinflammation, among others.

**2. Write the Henderson-Hasselbach equation.

Henderson Hasselbach- ** EXAM Q ** - equation: pH= pKa + log (concentration of base/concentration of acid) - In the biocarbonate system, HCO3- is the base, and H2CO3 is the acid, - so pH= pKa + log (HCO3-/H2CO3)

1. Contrast the local blood flow regulatory systems with the nervous control of blood flow.

Unlike the local control of blood flow in tissues, nervous control of the circulation has more global functions (eg., redistributing blood flow to different areas, regulating the pumping activity of the heart, , providing rapid control of blood pressure).

12. List the three most important urinary buffer systems.

Urinary buffer systems: -Phosphate -Ammonia -bicarbonate

High-voltage electrocardiogram in congenital pulmonary valve stenosis with right ventricular hypertrophy.

High-voltage electrocardiogram is where the sum of all three standard leads is greater than 4mV. It is due to increased heart muscle mass or hypertrophy (caused by excessive load on heart). Another common similar condition is hypertrophy of left ventricle caused by hypertension.

Iris:

Highly pigmented; forms a diaphragm that controls the amount of light passing through the lens and reaching the retina

describe the resting state/inhibited state of the actin filament

before contraction, the active site of the actin filament is inhibited (physically covered) by troponin- trpomyosin complex, preventing myosin from interacting.

CCK (stimulated by fat in duodenum) stimulates secretion of what

bile lipases and cholesterases

CCK (stimulated by fat in duodenum) stimulates secretion of what by the pancreas

bile lipases and cholesterases

3. Define the term "homeostasis" and list five examples of substances whose body fluid concentrations are homestatically controlled.

blood pH plasma sodium plasma osmolarity plasma calcium blood volume

the large influx of positively charged sodium ions through the acetylcholine channel creates local positive potential change inside the muscle fiber membrane; this potential is called

end plate potential -end plate potential initiates an action potential that spreads along the muscle membrane and thus causes muscle contraction.

in mitral stenosis, the mitral valve opening is narrowed, and blood flow from the where to where during diastole is reduced?

from the left atrium to the left ventricle

what carbohydrate is absorbed whether sodium is present or not

fructose

when the muscle does not shorten during contraction

isometric -isometric means "same length" -force develops (changes) -does not require much sliding of the myofibrils

11. What determines the magnitude of the stroke volume? What is the size of the stroke volume normally?

magnitude of stroke volume is determined by magnitude of end-diastolic pressure and the strength of the contraction (By both increasing the end-diastolic volume and decreasing the end-systolic volume, the stroke volume output can be increased to more than double normal.)

thick filaments are what protein

myosin

cortisol release is regulated by what type of mechanism

negative feedback

What is the Nernst potential equation and how is it utilized?

nernst potential: The potential level that prevents net diffusion of an ion in either direction is called the Nernst potential (electromotive force or EMF) for that ion.

smooth muscle can be stimulated to contract by multiple types of signals

nerve signals, hormones, stretch, etc.

what type of spindle nerve ending is responsible for dynamic response ((ie., responding extremely suddenly/strongly to rapid changes in length)

primary endings surrounding spindle intrafusal fibers -works only while the length is actively increasing -signals rate of change in length. -When the spindle receptor area shortens, impulse output momentarily deceases from primary ending, followed by reappearance of the static response impulse in the Ia fiber.

Smooth muscle contains both actin and myosin filaments having chemical characteristics similar to those of the actin and myosin filaments in skeletal muscle; however, it notably does not contain what component that is observed in skeletal muscle?

smooth muscle does not contain the normal troponin complex that is required in the control of skeletal muscle contraction, so the mechanism for control of contraction is different.

The diffusion of what ion determines the rate of development and extent of the action potential?

sodium ions

what is the "integrative area for reflexes and other motor functions"?

spinal cord

t/f About 125 vesicles usually rupture with each action potential.

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t/f Each actin filament is about 1 micrometer long. The bases of the actin filaments are inserted strongly into the Z discs; the ends of the filaments protrude in both directions to lie in the spaces between the myosin molecules,

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t/f Each villi in the small intestine has its own blood supply, lymphatic drainage system, and innervation.

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t/f Excessive inhibition of cortisol production results in serious adverse effects that can have impact on stressful dental procedures.

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t/f Large veins have little resistance to blood flow and with distension the resistance is almost zero.

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t/f Malignant Hyperthermia is NOT triggered by nitrous oxide

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t/f The amount of water diffusing in each direction is normally balanced and cell volume remains constant.

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t/f Velocity of conduction in nerve fibers varies from 0.25 m/sec in very small unmyelinated fiber to 100 m/sec in very large myelinated fiber.

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t/f both cardiac and smooth muscle are dependent upon the presence of extracellular calcium

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t/f during AP Na conductance increases several thousand-fold during the early stages of the AP, whereas K conductance increases only ~30-fold during the later stages of the AP and for a short period thereafter

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t/f facilitated diffusion approaches a maximum rate (Vmax), but not simple diffusion

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t/f fluoride is more rapidly absorbed from the GI tract when the contents of the stomach are strongly acidic; HF, no F- is absorbed

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t/f important feature of multiple fiber summation is that the different motor units are driven asyn- chronously by the spinal cord, so that contraction alternates among motor units one after the other, thus providing smooth contraction even at low frequencies of nerve signals.

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t/f in myelinated fibers action potentials occur only at the nodes.

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t/f in tetanization there is increased rate of contraction of individual motor units.

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t/f in the sarcoplasm surrounding the myofibrils of each muscle fiber is an extensive reticulum called the sarcoplasmic reticulum. This reticulum has a special organiza- tion that is extremely important in controlling muscle contraction. The very rapidly contracting types of muscle fibers have especially extensive sarcoplasmic reticula.

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t/f intestines, urinary bladder, gallbladder, and other viscera often maintain tonic muscle contraction almost indefinitely.

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t/f most control systems operate by negative feedback

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t/f only 2% of skeletal muscle fibers NOT are innervated by a single nerve ending

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t/f primary colors are blue, green and red. All colors, including white, can be made by mixing two or more primary colors.

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t/f salt and sweet have the LEAST sensitive thresholds

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t/f the A-V valves are supported by the chordae tendineae, which is not true for the semilunar valves.

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t/f when the voltage gated sodium channel is open this is called the activated state; during this state, sodium ions can pour inward through the channel, increasing the sodium permeability of the membrane as much as 500- to 5000-fold.

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• Stretching the heart muscle with extra blood causes the muscle to contract with increased force because...

the actin and myosin filaments are brought to a more optimal degree of interdigitation for force generation. This ability of stretched muscle, up to an optimum length, to contract with increased force is characteristic of all striated muscle.

How does the length-tension relationship of smooth muscle differ from that of cardiac or skeletal muscle.

the length-tension diagram above shows the length of smooth muscle tracking with the tension

7. Define mean arterial pressure and describe its physiological significance.

the mean arterial pressure is determined about 60 % by the diastolic pressure and 40 % by the systolic pressure (CO= cardiac output; TPR= total peripheral resistance) MAP = CO x TPR MAP obtained by a complex method, but may also be more easily estimated as: MAP = Diastolic + 1/3 Pulse Pressure

Stimulation of a single alpha nerve fiber excites anywhere from three to several hundred skeletal muscle fibers, which are collectively called

the motor unit.

intestinal absorption of calcium including the role of vitamin D and parathyroid hormone

​-Parathyroid hormone is secreted when Ca is low in the blood PTH -> activates vitamin D ->greatly enhances Ca reabsorption from renal tubules and Ca mobilization from bone -> increases plasma calcium -> reduces secretion of negative feedback loop

why can't glucose molecules diffuse through membrane lipid bilayer or channels/pores readily (ie., by simple diffusion)?

• It is not lipid soluble (look at its structure). • It is too big to pass through water-filled channels (like the sodium channels).

Describe the role of negative feedback in maintaining homeostasis.

-cortisol release -respiratory stimulation by elevated CO2 concentration

17. List the major factors responsible for lymph flow.

1) interstitial fluid pressure 2) degree of activity of lymphatic pump

7 primary odors

1. camphoraceous 2. Musky 3. Floral 4. Pepperminty 5. Ethereal 6. Pungent 7. Putrid

normally, blood glucose is maintained at a narrow range of?

80-120 mg%

what is the order of the venous waves

A C V

This is another powerful/potent vasoconstrictor, specially affecting the small arterioles. However, the overall effect of angiotensin II is that it normally acts on many arterioles of the body at the same time increases the TPR, thereby increasing arterial/blood pressure. Thus, angiotensin II plays an integral role in the regulation of arterial pressure.

Angiotensin II

t/f ATPase activity of the myosin head is essential for muscle contraction

As explained later, this property allows the head to cleave ATP and to use the energy derived from the ATP's high-energy phosphate bond to energize the contrac- tion process.

The pressure that the ventricle must generate in order to eject blood out of the heart. For the left ventricle afterload is a function of the aortic pressure.

Afterload:

Amblyopia:

Also called "lazy eye." Due to a refractive error causing blurred vision in the affected eye. Can be corrected by muscle shortening, muscle training or glasses with special prisms.

12. Describe the intestinal mechanisms for the neutralization of gastric HC1.

Neutralization of HCl- bicarbonate (present in the saliva, and also secreted by the pancreas) neutralize the gastric acid

about how much of the energy input of SKM contraction is converted to work

Only 20-25% of the energy input is converted to work.

osmolarity vs. tonicity

Osmolality is a chemical (concentration) measurement. Tonicity is a biologic measurement, done using a cell as an osmometer. If one places a cell in an isotonic solution (same water concentration as in cells), it will not change volume.

retinal detachment.

Potentially serious separation of retina from pigment epithelium which reduces retinal nutrition. -Causes- Injury (blows to the head, for example) that cause fluid or blood to pool between the retina and the epithelium, or pulling of the retina by fine fibrils in the vitreous humor -Symptoms- Early symptoms= dark or irregular "floaters", flashes of light, and blurred vision. Total detachment and destruction of the retina results in blindness. -correctable by laser surgery

heart sounds are associated with closure or opening of valves?

Sounds are associated with closure of valves, but not opening.

stimulators and inhibitor of gastric acid secretion

Stimulators: Gastrin Acetylcholine Histamine Inhibitor: Prostaglandin

Pupil:

The aperture of the iris

The average refractive power of the human eye is _ diopters so the average focal length is _ mm.

The average refractive power of the human eye is 59 diopters so the average focal length is 17 mm.

6. State the location of most of the parasympathetic nervous system (PNS) ganglia.

The ganglia of the parasympathetic nervous system are found very close to (or INSIDE) the effected organ

Receptor area of the spindle also has two types of sensory nerve endings that spiral around the intrafusal fibers; describe these...

The primary (large myelinated Ia sensory fiber) and secondary endings (type II) are stimulated when the receptor portion of the spindle is stretched 1 - large fiber/signal is transmitted to cord fast (70-120 m/sec) 2 - smaller diameter and slower velocity.

threshold concentration of methylmercaptan and the gradations in smell intensities with concentration.

Threshold for smell: -We can smell methyl mercaptan (what they put in natural gas) at a concentration of 1 billionth of a mg/ml of air. - Gradation in smell intensity- maximum intensity is usually reached at 10-50 times the threshold intensity. So as the concentration increases above this, we can tell no difference in smell intensity

pigment epithelium

absorbs light rays preventing reflection of light rays back through the retina which would cause blurring of visual images by scattering light.

examples of a multi-unit smooth muscle

ciliary muscle of the eye, the iris muscle of the eye, and the piloerector muscles that cause erection of the hairs when stimulated by the sympathetic nervous system.

first heart sound (lub) is caused by

closure of AV valves at beginning of systole

systole

contraction of ventricle

what enables cardiac cells to excite surrounding cardiac cells

gap junctions at intercalated discs

basic chemical process for the digestion of fats, carbohydrates and proteins?

happens by HYDROLYSIS

what is generated in a nerve fiber at progressively increasing rates of stimulation?

heat

why is vitreous humor (or body) viscous?

held together by proteoglycan molecules.

whats the cause of high output

hypertonicity of fluid in medullary regions was sharply reduced with regard to the F concentration

absorption of nutrients occurs mainly in the _ _

small intestine

PNS is said to be more specific than the sympathetic

t

Management considerations can include aspects stated below

Routine measurement of blood pressure and review of health status of patients, particularly for those with known hypertension. Patients with Stage 1 hypertension or with well-controlled hypertension are good candidate for all dental procedures. Moderate hypertension is not considered an independent risk factor for perioprative cardiovascular complications; however, risk assessment is essential for all patients, especially those in which complicated or surgical procedures are expected. Particular care should be made to identify risk factors for hypertension and target organ damage/cardiovascular diseases that indicate increased risk. Sedation with an anxiolytic agent or nitrous oxide may be indicated for anxious (nervous) individuals.

8. Describe the mechanism of development of "Goldblatt Hypertension".

"One-Kidney" Goldblatt Hypertension When one kidney is removed and a constrictor is placed on the renal artery of the other kidney, hypertension eventually developes (Figure 19-14). This type of hypertension is called "one-kidney" Goldblatt hypertension. The early rise in arterial pressure in Goldblatt hypertension is caused by the renin-angiotensin vasoconstrictor mechanism. The second rise in is caused by retention of salt and water by the constricted kidney. A similar scenario occurs in patients with stenosis of the renal artery of a single remaining kidney, as sometimes occurs after a person receives a kidney transplant. "Two-Kidney" Goldblatt Hypertension Hypertension also can result when the artery to only one kidney is constricted while the artery to the other kidney is normal. The clinical counterpart of "two-kidney Goldblatt" hypertension occurs when there is stenosis of a single renal artery, for example caused by atherosclerosis, in a person who has two kidneys.

7. Describe the intrarenal changes that lead to increased blood pressure in "Goldblatt hypertension."

"one kidney"- When one kidney is removed, and a constrictor is placed on the renal artery of the remaining kidney, blood pressure in the renal artery ↓ beyond this constrictor (less blood entering the kidney = ↓ Pc (remember starling forces - A drop in pressure stimulates the kidneys to make LOTS of renin -renin stimulates Angiotensin II -Angiotensin raises blood pressure, trying to get the pressure inside the kidney back to normal. - "two kidney" This type of hypertension also occurs when part of one renal artery is blocked. The ischemic artery secretes renin, and both kidneys are effected by it -"patchy ischemic kidney disease" - patches of the kidneys become blocked, and these areas secrete renin. The result is the same

what is "resting" membrane potential in the rythmic control center of the heart

"resting" membrane potential in the rhythmi- cal control center of the heart is only -60 to -70 milli- volts. This is not enough negative voltage to keep the sodium and calcium channels totally closed. Therefore, the following sequence occurs: (1) some sodium and calcium ions flow inward; (2) this increases the mem- brane voltage in the positive direction, which further increases membrane permeability; (3) still more ions flow inward; and (4) the permeability increases more, and so on, until an action potential is generated. Then, at the end of the action potential, the membrane re- polarizes. After another delay of milliseconds or seconds, spontaneous excitability causes depolarization again, and a new action potential occurs sponta- neously. This cycle continues over and over and causes self-induced rhythmical excitation of the excitable tissue.

Several hours after death, all the muscles of the body go into a state of contracture called

"rigor mortis" the muscles contract and become rigid, even without action potentials. This rigidity results from loss of all the ATP, which is required to cause separation of the cross- bridges from the actin filaments during the relaxation process. The muscles remain in rigor until the muscle proteins deteriorate about 15 to 25 hours later, which presumably results from autolysis caused by enzymes released from lysosomes. All these events occur more rapidly at higher temperatures.

24. Describe the action of the enterogastric reflex and list the factors that can activate it.

#24 Enterogastric reflex= keeps food from entering the duodenum too fast- slows emptying in response to large volumes of food. This is important because the greatest threat to the duodenum is too much stomach acid entering too quickly. This reflex gives the gut enough time to use its defenses against the acid. Factors that stimulate this reflex: - degree of distention (stretch) of duodenum - presence of any degree of irritation of the duodenal mucosa - degree of acidity of duodenal chyme - degree of osmolarity of chyme - presence of certain breakdown products in the chyme, especially breakdown products of proteins and perhaps to a lesser extent, fats.

6. Describe the features of the nephrotic syndrome.

#6- Nephrotic Syndrome -As a result of glomerulonephritis, the glomerular capillary cells become "leaky" to plasma proteins. Proteins are LOST in the urine. - remember STARLING FORCES- the decrease in πc will increase fluid movement OUT of the capillary. This can cause EDEMA.

4. Define hematocrit.

% or RBC's in blood as determined by centrifuging blood in "hematocrit" tube" until cells become packed tightly in the bottom of tube

Summation occurs in two ways:

(1) by increasing the number of motor units contracting simultaneously, which is called multiple fiber summation (2) by increasing the frequency of contraction, which is called frequency summation and can lead to tetanization.

Volume of blood pumped by the heart is regulated in two ways

(1) intrinsic mechanism responsive to changes in volume of blood in heart and (2) the autonomic nervous system.

Probably half of all smooth muscle contraction is initiated by stimulatory factors acting directly on the smooth muscle contractile machinery and without action potentials. Two types of non-nervous and non-action potential stimulating factors often involved are ?

(1) local tissue chemical factors and (2) various hormones.

Two particular classes of substances are especially likely to cause bitter sensations:

(1) long-chain organic substances and (2) alkaloids. The alkaloids include many of the drugs used in medicines, such as quinine, caffeine, strychnine, and nicotine.

in contraction, most of the ATP used is required to actuate the walk-along mechanism by which the cross-bridges pull the actin filaments, but small amounts are required for what other two actions?

(1) pumping calcium ions from the sarcoplasm into the sarcoplasmic retic- ulum after the contraction is over (2) pumping sodium and potassium ions through the muscle fiber membrane to maintain appropriate ionic environment for propagation of muscle fiber action potentials.

examples for primary active transport:

(1) sodium-potassium pump for transport of Na and K ions, respectively, outward and inward, and (2) calcium pump in SR of skeletal muscle.

sensory information coming into the cord:

(1) synapses on cord gray matter anterior horn motor neurons or interneurons (2) has a second branch ascending the cord to a higher level of the cord (intersegmental reflexes), (2) to the brain stem or (3) to the cerebral cortex.

an analysis of the lever systems of the body depends on knowledge of

(1) the point of muscle insertion, (2) its distance from the fulcrum of the lever (3) the length of the lever arm (4) the position of the lever.

Myosin molecule (A) and Myosin filament (B) which is composed of multiple myosin molecules. Also shown are myosin cross-bridges and interaction between the heads of the cross-bridges with adjacent actin filaments

(A) myosin molecule is composed of six polypeptide chains—two heavy chains, and four light chains -The two heavy chains wrap spirally around each other to form a double helix, which is called the tail of the myosin molecule. One end of each of these chains is folded bilaterally into a globular polypeptide structure called a myosin head. Thus, there are two free heads at one end of the double-helix myosin molecule. The four light chains are also part of the myosin head, two to each head. These light chains help control the func- tion of the head during muscle contraction. (B)The myosin filament is made up of 200 or more individual myosin molecules. -The total length of each myosin filament is uniform, almost exactly 1.6 micrometers. (Note, however, that there are no cross-bridge heads in the very center of the myosin filament for a distance of about 0.2 micrometer because the hinged arms extend away from the center. -Now, to complete the picture, the myosin filament itself is twisted so that each successive pair of cross- bridges is axially displaced from the previous pair by 120 degrees. This ensures that the cross-bridges extend in all directions around the filament.

Ventricular fibrillation

(Generally bizarre pattern and no tendency towards regular rhythm)

4. List the major sphincters of the alimentary tract and state their locations.

(Hyper guy played in excitement) 1-hyperpharyngeal sphincter- connects the pharynx to the upper esophagus. This sphincter relaxes when you swallow, allowing food to move into the esophagus 2-gastroesophageal (or cardiac) sphincter- connects esophagus to stomach. Allows food to pass through. When closed, it prevents the reflux of stomach acid into the esophagus 3- pyloric sphincter- connects stomach and small intestine- controls how fast the acidic contents of the stomach enter the duodenum 4- ileocecal sphincter- connects ilium of sm.intestine to large intestine 5- external and internal anal sphincters- control defecation. - are always contracted unless consciously relaxed

t/f The refractory period of atrial muscle is much shorter than that for the ventricles

(about 0.15 second for the atria compared with 0.25 to 0.30 second for the ventricles).

16. Describe the control mechanisms which regulate the ECF concentrations of calcium.

(rang of %10 Ca is normal) -three mechs -each regulated by parathyroid hormone -when plasma [Ca] is low, parathyroid hormone is released which increases Vit D3 in kidney which increases intestinal Ca absorption and increases rate of Ca reabsorption in kidney tubule; parathyroid hormone also stimulates osteoclasts to release Ca from bone

**end of organization of retina**

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**organization of retina**

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**7. State the magnitude of the maximum pH gradient between the ECF and the renal tubular fluid.

** EXAM Q ** :Maximum pH gradient between ECF and renal tubular fluid (urine). -The maximum difference between the ECF and urine is 3 pH units - So a 3 unit difference is actually a THOUSAND times difference -After a 3 unit difference, the gradient is so large that the rate of passive diffusion of H+ back into the ECF increases, and it balances the active transport.

hypothermia

** This is an ABNORMAL condition ** (read the article attached to the outline about hypothermia, there WILL be test questions covering it) 1- Temperature of the core decreases. If it falls <77 F, this is fatal. If ice crystals form inside tissue, it is very damaging 2- Hibernation

***Chapter 10

***

time required to oxidize 10 kg (22 lbs) of excess body fat. (handout)

- 10kg of excess body fat: 10,000gm fat x 9Cal/gm fat = 90,000 Calories If the patient consumed no food (and did not increase their metabolic rate): 90,000 Calories/ 2,400Cal/day = 37.5 days

9. State the approximate percentage of PNS nerves that are carried in the vagus nerve and what general areas of the body these nerves innervate.

- 75% of parasympathetic fibers are carried by the vagus nerve!!!!! - these fibers innervate heart and GI tract... NOT THE HEAD

18. Define acidosis and alkalosis.

- Acidosis- when blood pH falls below 7.4 - Alkalosis- when blood pH rises above 7.4

10. State why cells of the adrenal medulla are considered part of the SNS.

- Adrenal medulla- important to the sympathetic nervous system! - Adrenal medulla cells were embryonically derived from nervous tissue - When the sympathetic nervous system is stimulated, the adrenal medulla releases norepinephrine and epinephrine into the bloodstream - So the effected organs are stimulated in two ways: -1- by the sympathetic fibers that synapse on them and release neurotransmitters -2- by the EPI and NE secreted by the adrenal medulla - the effect of the EPI and NE from the adrenal medulla lasts a lot longer than the effect of the sympathetic fibers.

**11. Name the basic propulsive movement of the GI tract and state why its direction is analward.

- Basic Propulsive movement= peristalsis - movement is analward- this is the LAW OF THE GUT *** EXAM Q *** -2 factors that cause this: 1- the frequency of slow waves is different in different parts of the sm. intestine. Upper sm. intestine= 12-15 waves/minute. Mid ilium= 8 waves/minute, end of ilium = 4waves/minute 2- Sphincters- keep chyme from moving in the other direction

11. Name the basic propulsive movement of the GI tract and state why its direction is analward.

- Basic Propulsive movement= peristalsis - movement is analward- this is the LAW OF THE GUT *** EXAM Q *** -2 factors that cause this: 1- the frequency of slow waves is different in different parts of the sm. intestine. Upper sm. intestine= 12-15 waves/minute. Mid ilium= 8 waves/minute, end of ilium = 4waves/minute 2- Sphincters- keep chyme from moving in the other direction

acetylcholine receptor blocker drugs cause contraction similar to Ach; What are 2 categories of receptor blockers

- Competitive blockers/antagonists - Noncompetitive blockers

21. Describe the composition of bile and its physiologic function.

- Composition of bile -Bile salts, billirubin, cholesterol, fatty acids, lecithin, Na, K, Ca, Cl, bicarbonate (see Table 64-2) -As bile is stored in gallbladder, it becomes much more concentrated -Function- emulsifies fat, so that it can be absorbed

digestion of the major carbohydrate types

- Digestion of carbohydrates: When carbohydrates enter the mouth, they first encounter PTYALIN, (an alpha-amylase) which breaks down starches into maltose and other glucose polymers. But, only 5% of the starch is digested in the mouth. ​ ​ ​ ​ -In the stomach: the starch is churned in the fundus and body for a while before it enters the part of the stomach which has acid secretions. In that time, the ptyalin continues to act, and 40% of the starch is broken down. -In the duodenum: Pancreatic amylase finishes breaking down the rest of the starch into small glucose polymers - In the villi of the small intestine, enterocytes release lactase, sucrase, maltase, and alpha-dextrinase. These enzymes break up the small glucose polymers -​ These monosacharides are immediately absorbed into the portal blood

20. List the major enzymes of the exocrine pancreas and state their major functions.

- Digestive enzymes of the pancreas a) trypsin- cleaves protein b)chymotrypsin- cleaves protein c) carboxypeptidase- splits peptides into individual amino acids d) amylase- breaks down carbohydrates e) lipase- breaks down fat f) cholesterol esterase- breaks down cholesterol esters g) phospholipase- splits fatty acids from phospholipids

acetylcholine receptor activator drugs cause contraction similar to Ach; What are 2 categories of Ach receptor activators?

- Direct acting drugs/agonists - Indirect acting drugs/Achase inhibitors (anticholinesterases)

6. Describe the distribution of the enteric nervous system, the myenteric plexus, Auerbach's plexus, the submucosal plexus and Meissner's plexus; and physiological function

- Enteric nervous system- intrinsic nerve fibers in the GI. They can function independently (do not need outside stimulus). - myenteric plexus= Auerbach's plexus: located between longitudinal and circular layers, is longitudinal/linear... travels the entire length of the GI Controls motility down the entire length of the gut. Action: increases intensity and frequency of rhythmic contractions, increses conduction of excititory waves -submucosal plexus = Meisner's plexus: between mucosa and circular layers. Effects minute sections of the gut, one at a time. Controls local secretion, absorption, and contraction of submucosal muscle.

5. List the exocrine and endocrine secretions of the alimentary tract, their sources, the stimuli for their secretion and their major physiologic functions.

- Exocrine and Endocrine secretion -Exocrine= mucous, saliva, ions (such as bicarbonate) digestive enzymes, bile, intrinsic factore (these all have been/will be discussed in other BO's) -Endocrine= hormones a) gastrin- secreted by G cells in pyloric glands in stomach. Stimulated by chyme. Stimulates the secretion of HCL by parietal cells, and relaxes the ileosecal sphincter b) secretin- secreted by epithelial cells of the duodenum. Stimulated by chyme, especially very acidic chyme. Effect= stimulates secretion of bicarbonate from pacreas, which enters the duodenum and neutralizes the acid (negative feedback) *** EXAM Q *** Secretin also slows down the gastric pump c) CCK-secreted by jejunum. Stimulated by polypeptides and fats. Effect = stimulates the release of digestive enzymes into the duodenum, and inhibits pyloric pump. d) GIP (I can't find what this stands for! sorry! I think it might be gastro-intestinal peptide... I know P stands for peptide, at least) - from jejunum, stimulated by fat and amino acids, inhibits gastric motility and secretion

location and interrelationship between the feeding and satiety "centers".

- Feeding center= lateral hypothalamic nucleus. (inhibition causes lack of hunger) -Satiety center= ventromedial nucleus of the hypothalamus. (destruction causes huge increase in food intake)

14. State the cell type that secretes the hormone gastrin and the major actions of gastrin.

- Gastrin- secreted G cells in pyloric gland cells. Stimulates the secretion of HCL by parietal cells, and relaxes the ileosecal sphincter

**9. State the step of the bicarbonate buffer system which is catalyzed by carbonic anhydrase.

- H2O + CO2 ↔H2CO3 - This reaction would be ULTRA SLOW without carbonic anhydrase -If carbonic anhydrase was not there, this buffer system wouldn't work - carbonic anhydrase is prevalent in the lungs (where there is a lot of CO2, and in the kidney tubules

27. Describe the physiologic aspects of defecation including their control.

- Initiated by two reflexes, intrinsic and parasympathetic -Intrinsic reflex= distention of the rectum stimulates myenteric plexus, initiates peristaltic waves that push feces toward anus -Parasympathetic reflex = intensifies the peristaltic waves ...

sprue

- Intestinal malabsorptive disorder with steatorrhea (fat in feces) in which microvilli or even the villi are missing or blunted - Idiopathic or Non-tropical sprue: Hereditary disorder caused by reaction to the gliadin fraction of gluten ("vegetable albumin") • Gliadin acts as an antigen forming an immune complex on the mucosa that promotes aggregation of killer lymphocytes • Tx: Remove wheat and rye flour from diet - Tropical sprue: Acquired disorder of unknown etiology. Possibly caused by a variety of largely unidentified bacteria, viruses or parasites. Occurs in Caribbean, Southern India, Southeast Asia. • Tx: Antibacterial agents, especially tetracycline - Malabsorption of most nutrients including sugars, fats, proteins, calcium, folic acid, vitamins K and B12 - Signs/symptoms: wasting, osteomalacia, inadequate blood coagulation, pernicious anemia

approximate caloric content of one liter of 5% (isotonic) glucose in water and state how much that contributes to the daily energy requirement of an individual. (handout)

- Isotonic glucose (has the same osmolarity as ECF) = 300mOsm/L 5% = 5gm/100ml (Refer back to Dr. Whitford's calculations if you need to) = 50gm/1L 50gm/L x 4Cal/gm = 200Cal/Liter One liter of this solution will provide 200 Calories to the patient. This is only 8% of their daily caloric needs!! (Lesson- you cannot feed a patient sufficiently with sugar water—use fat instead)

3. List the major layers of the intestinal wall in sequence from the serosa to the mucosa.

- Layers= Serosa → Longitudinal muscle → Circular muscle → submucosa → mucosa- sera loved cirus so much

19. State the locations and functions of the (see pg. 751): a. gallbladder; b. cystic duct; c. hepatic duct; d. common bile duct; e. pancreatic duct; f. Sphincter of Oddi.

- Locations and functions: (several of these not discussed in class) a) gallbladder- underneath the liver- stores and concentrates bile secreted by liver cells b) cystic duct- empties into the gallbladder- bile flows from the liver into the cystic duct, or straight into the duodenum c/d) hepatic and common bile duct- bile empties into these ducts from smaller ducts e) pancreatic duct- carries bile from common bile duct to pancreas f) Sphincter of Oddi- guards the opening of the common bile duct into the duodenum, controls the movement of bile into the sm. intestine.

20. Describe the function and control of the pyloric pump.

- Most of the time, contractions in the stomach serve to mix the chyme, but about 20% of the time, the contractions become very intense, peristaltic in action. This pushes chyme out of the stomach into the duodenum. Each strong peristaltic wave pushes several mL's of chyme into the duodenum.

List the major factors or mechanisms that normally neutralize gastric acid.

- Neutralizing gastric acid: 1​) mucous layer with bicarbonate ions 2​) tight junctions ​3) blood supply

Define "partial" and "complete" proteins and state the physiologic consequences of ingesting excessive amounts of "partial proteins".

- PARTIAL/INCOMPLETE PROTEIN- protein source that is missing one or more of the 10 essential amino acids - COMPLETE PROTEIN- protein source has all 10 essential amino acids -Most animal sources of protein (meat, eggs) are complete -Vegetable sources of protein are incomplete (corn is missing trp, for example) -Consuming lots of partial proteins will cause you to be deficient in one or more essential amino acids

17. Describe the volume flow rate and the composition of pancreatic secretions when the gland is stimulated by: a. secretin; b. cholecystokinin (CCK); c. acetylcholine.

- Pancreatic secretions in response to stimulation: ** remember that the pancreas is the major source of digestive enzymes ** a) secretin- *** EXAM Q *** stimulates secretion of large quantities of sodium bicarbonate solution by the ductal epithelium, but does not stimulate enzyme secretion b) CCK- stimulate the acinar cells of the pancreas (not the ductal cells). This causes production of large quantities of digestive enzymes, but not much fluid. The enzymes remain stored in the acini and ducts until more fluid secretion comes along to wash them into the duodenum c) Ach- same reaction as CCK

visceral smooth muscle AP occur in 2 forms:

- Spike potentials (in most single-unit; can be caused by electrical stimulation, stretch, hormones, NT, potential, or spontaneously) - AP with plateaus (delayed repolarization, plateau accounting for prolonged contraction of ureter, uterus, etc.).

1. State the primary function of the alimentary tract.

- The alimentary tract supplies the body with water, electrolytes and nutrients by: -digestion -secretion - absorption - motility

1. State the primary function of the alimentary tract.

- The alimentary tract supplies the body with water, electrolytes and nutrients by: -digestion -secretion - absorption - motility (the book adds two more- circulation of blood through GI to carry away absorbed substances, and control of these functions by nervous and hormonal systems)

astigmatism. Is it in lens or cornea?

- The defect responsible for astigmatism is usually in the CORNEA (although it may be in the lens- this is more rare) -If the cornea is "saggy", more shaped like a football or egg than spherical, this causes astigmatism -This "saggy" shape causes light to be refracted differently depending on the plane of the light -So, the light is focused in a line, instead of a point. -This is corrected by making a lens that is cylindrical, and also has a spherical correction -It is important to find the correct "axis" of the astigmatism in order to get the corrective lens made right

19. Compare and contrast the effects of SNS stimulation on an effector with those of epinephrine and norepinephrine from the adrenal medulla on the same effector.

- also not discussed in class - in general, the EPI and NE sereted by the adrenal medulla has the same effect as sympathetic stimulation. -The DIFFERENCE is that the hormones secreted by the medulla last a lot longer (hang around in the blood stream) so they can effect an organ for a long period of time after sympathetic stimulation has stopped.

Describe 2 characteristics related to saltatory conduction that provides a functional advantage to the organism.

- by causing the depolarization process to jump long intervals along the axis of the nerve fiber, this mechanism increases the velocity of nerve transmission in myelinated fibers as much as 5- to 50-fold. -saltatory conduction conserves energy for the axon because only the nodes depolarize, allowing perhaps 100 times less loss of ions than would otherwise be necessary, and therefore requiring little metabolism for reestablishing the sodium and potassium concentration differences across the membrane after a series of nerve impulses.

8. State the spinal origins of the PNS.

- cranial-sacral - -fibers come from cranial nerves (3, 7, 9, 10) and sacral segments of the spinal cord (S2 and S3)

2. List the major anatomical parts of the alimentary canal and state the specific functions for which each is adapted.

- esophagus- movement of food down to the stomach - stomach- secretion of acid, gross digestion -small intestine- ABSORPTION!!! (Parts of the small intestine- duodenum (first 6cm) jejunum (next 3 feet) ilium (remaining 20feet)) -large intestine-waste storage and defecation (Parts of large intestine- cecum, ascending colon, descending colon) -Associated organs= salivary glands, liver, gallbladder, pancreas

21. State the local response elicited when a section of the stomach or intestine is stretched.

- in general, stretch of smooth muscle in the GI tract causes depolarization, which pushes the muscle above its threshold, and causes a spike potential, and contracts the muscle

5. List 3 factors that cause hypoeffective hearts.

- inhibition of nervous excitation - pathological factors affecting rhythm or rate of heart - valvular heart disease - hypertension (increased pressure against which the heart must pump) - coronary artery blockage - congenital heart disease - cardiac hypoxia - myocarditis (inflammation of heart muscle) - other factors such as toxicity

2. List the types of cells that secrete mucus, where they can be found in the alimentary tract and the stimuli that can cause the secretion of mucus.

- mucous cells or goblet cells secrete mucous. -Many glands in the GI secrete mucous (along with other things) -simple and compound mucous glands- in the esophagus - Oxytinic glands- mucous neck cells secrete mucous and some pepsinogin - pyloric glands- have many mucous neck cells that are identical to those in oxytinic glands - surface mucous cells- continuous layer of mucous cells that covers the entire surface of the stomach mucosa -Brunner's glands *** EXAM Q *** - Located in the first 4-5 cm of duodenum- have lots of mucous cells, protects duodenum from acid digestion -Stimulation (?)- parasympathetic vagal stimulation, also stimulated by irritation of mucosa ...

6. Describe the overall process of hydrogen ion secretion by the kidney.

- occurs throughout the nephron (proximal tubule, loop of Henle, and distal tubule - mechanism in proximal tubule= countertransport! - H+ is actively transported from the tubule epithelial cells into the tuble (into the urine). The energy for this transport comes from coupling it with the reabsorption of Na+. Na+ is moving down its concentration gradient (from outside the cell into the cell) This is energetically favorable. H+ "piggybacks" on this energy to go UP its concentration gradient. (there are allready more H+ ions in the urine, but more can be actively secreted into the urine.) - This contributes to the reabsorption of bicarbonate! - Mechanism in late distal tubule and collecting duct= primary active transport: The cell uses ATP to actively secrete H+ out into the tubule lumen

Discuss the role of physiology in the education and practice of a dentist.

- physiology - Study of the function of living organisms -human physiology - Integrated study of the functional system of the human body (from molecular interactions to behavior)

10. State the cell type which secretes HC1 into the lumen of the stomach and describe the mechanism for the secretion of HC1.

- secretion of HCl- from parietal (or oxytinic ) cells in the Oxytinic glands. - mechanism- - Oxytinic cells have canaliculi (infoldings) into which they secrete stuff - Cl is actively exported from the cells - Inside the cells, water dissociates into H+ and OH- - H+ is exported from the cell in exchange for K+ ( -Cl- and H+ join in the canaliculi to form HCl

Overall, muscle spindles are responsible for normal muscle tone and upright posture

-(Example: gravity acting on mandible and attached structures stretches spindles in mandibular elevators, activating the proprioceptor nerves to fire. These nerves synapse on α-motor neurons innervating extrafusal fibers, causing slight contraction and preventing effects of gravity from pulling the mouth open. This is called stretch or myotatic reflex). -one of the most important functions of muscle spindle is to stabilize body position during tense motion action (by transmission of excitatory signals from bulboreticular facilitatory region and its allied areas of brain stem via the γ nerve fibers - a mechanism that shortens/contracts the ends and stretches the central spindle receptor region, increasing signal output).

mammalian skeletal muscle has how many t-tubules per sarcomere and where are they located?

-2 t-tubules/sarcomere -located at the A-I band junctions.

digestion of the major carbohydrate types

-5% of starch digested by PTYALIN, (an alpha-amylase) in MOUTH (breaks down starches into maltose and other glucose polymers. ​ ​ ​ ​ -40% of starch digested by PTALYIN in fundus and body of stomach aided by acid -50-80% of starch digested by PANCREATIC AMYLASE in the duodenum (into small glucose polymers) - lactase, sucrase, maltase, and alpha-dextrinase by villi of the small intestine enterocytes. (break up the small glucose polymers) -​ monosacharides are immediately absorbed into the portal blood

resting membrane potential in smooth muscle is usually what and how does it compare to that of skeletal muscle?

-50 mV to -60 mV (30 mV less negative than that of skeletal muscle)

percent composition of feces

-75% water -25% solids 1. 30% bacteria 2. 10-20% fat 3. 10-20% inorganic 4. 30% undigested roughage and desquamated cells -Color due to stercobilin and urobilin (bilirubin metabolites)

2. Describe the quantities of blood in different functional parts of the circulation.

-84 % of the entire blood volume is in the systemic circulation and 16 % is in the heart and lungs. -64% of the 84 % blood in the systemic circulation is in the veins, 13 % in the arteries, and 7 % in the systemic arterioles and capillaries. -The heart has 7 % of the blood, and the pulmonary vessels, 9 %. [The low blood volume in the capillaries is surprising since most important functions of the circulation occurs here (diffusion of substances back and forth between the blood and tissues).]

in sodium and potassium diffusion, the potential differences required to block further net diffusion of the ions

-94 mV for K and +61 mV for Na.

role of hemoglobin

-97% percent oxygen is bound to HG -25% bound CO2 (75% is bicarbonate)

**15. State the pH at which a buffer system is most effective. Specify the pKa of the bicarbonate buffer system and the ratio of [HCO3-]/[H2CO3] at pH 7.4.

-A buffer is ALWAYS most effective at a pH equal to its pKa. (At this pH, half of the buffer is in acid form, and half is in base form, so it is ready to resist change in either direction, acidic or basic) - Most buffers are pretty effective within 1 pH unit above or below their pKa - pKa of bicarbonate = 6.1 - This is really weird. You would not expect a buffer with this pKa to be physiologically relevant, because the pH of our bodies is 7.4. So bicarbonate is not at its most effective. Also, there is not a whole lot of bicarbonate around. This makes it even wierder that it is such an IMPORTANT buffer. - The reason it is important despite these things is that it is REGULATED by the lungs and the kidneys - plug the pKa of bicarbonate into the Hend/Hass equation (BO #2) to see the normal ratio of acid (H2CO3) to base (HCO3) that is needed to keep our bodies at pH 7.4 pH= pKa + log base/acid 7.4 = 6.1 + log base/acid 1.3 = log base/acid ** Since you cannot measure the concentration of H2CO3 directly, you can substitute CO2 concentration for it. antilog 1.3 = HCO3/ CO2 = 20 SO... the ratio of HCO3/ CO2 must be kept at 20!!! - What happens if the ratio changes??? *** EXAM Q *** - if HCO3 ↑, but CO2 doesnt, the ratio ↑, and pH ↑ (alkalosis) - if CO2 ↑, but HCO3 doesnt, the ratio ↓, and pH↓ (acidosis) - when either concentration changes, the lungs or kidneys makes up for it to keep the ratio at 20!

What is diffusion?

-A single molecule in a solution bounces among other molecules first in one direction, then in another and so forth, bouncing randomly billion of times each second. This continual random movement of molecules/ions in liquids, or in gases, is termed diffusion. Kinetic motion is the energy that causes diffusion. -

What is saltatory conduction? How does it occur?

-AP conduction from node to node (jumping of nerve impulses) -electrical current flows through the surrounding extracellular fluid outside the myelin sheath as well as through the axoplasm inside the axon from node to node, exciting successive nodes one after another.

Compare the energy utilization during the action potential and the recharging process.

-ATP is needed to reestablish sodium and potassium ionic gradients after action potentials are completed

what primes the mechanism of contraction? (site of ATP cleavage before contraction begins)

-ATPase activity of the myosin head -The energy that activates the power stroke is the energy already stored, like a "cocked" spring, by the conformational change that occurred in the head when the ATP molecule was cleaved earlier.

9. Define cardiac arrhythmias.

-Abnormal rhythm of the heart resulting from conduction impairment of impulses. It often leads to cardiac malfunction. -Causes: Abnormal rhythmicity of the pacemaker Shift of the pacemaker from the sinus node to another place in the heart Blocks at different points in the spread of the impulse through the heart Abnormal pathways of impulse transmission through the heart Spontaneous generation of spurious impulses in almost any part of the heart

what are two types of neurotransmitters in the varicosities of smooth muscle?

-Ach -norepinephrine (never secreted by the same nerve fibers; Ach is an excitatory transmitter substance for smooth muscle fibers in some organs but an inhibitory transmitter for smooth muscle in other organs. When Ach excites a muscle fiber, norepinephrine ordinarily inhibits it. Conversely, when acetylcholine inhibits a fiber, norepinephrine usually excites it.)

1. Define the following terms: acid; base; ampholyte; acidity; alkalinity; buffer; pH; pKa.

-Acid- a molecule that can donate a hydrogen ion (H+) -Base- a molecule that can accept a hydrogen ion -Ampholyte (not discussed in class)- a molecule with both acid and base properties. (ex. protein with both acid and base side groups; ampholytes are very good buffers) -acidity- ability of a substance to donate its H+. -alkalinity- The ability of a substance to accept free H+. The more sites that can accept H+, the higher the alkalinity -buffer- ability to combine with or release H+; resist pH changes (If acid is added, the buffer picks it up. If base is added, the buffer releases H+ to add to the base) - pH= -log[H+] (-log of hydrogen ion concentration) [H+] pH -pKa- pKa is the dissociation constant for any acid/base combination. A substance's pKa will tell you how much of the substance exists as the acid, and how much exists as the base at any given time (as long as you know the pH of the solution)

absorption of carbohydrates

-Almost all carbs are absorbed as monosacharides. -Glucose accounts for ~80% of carbohydrate calories absorbed - Glucose transport is through a Sodium co-transport mechanism Glucose can enter cells (going up its concentration gradient) because it is "piggybacking" on the energy released when Na cells slowly leak out of the cell DOWN their concentration gradient -protein carrier is specific for 6-carbon d-hexoses -sodium absolutely required to occupy carrier protein that transports the hexose -Tx for cholera orally administered with glucose to promote sodium and water reabsorption

1. What is the normal value for cardiac output?

-Average CO is ~ 5 L/min (reduced with advancing age due to decreased activity, etc). -Quantity of blood pumped by the heart/left ventricle into the aorta per minute.

Muscle spindles can be stimulated in 2 ways

-By stretching the whole muscle. That is, lengthening the entire muscle and thus stretching the primary endings (sensory) in the muscle spindles. -By contracting the intrafusal muscle fibers (via gamma motor neuron) while the extrafusal fibers remain at their normal length. This, too, will stretch the primary ending in the spindle.

predominant chemical forms of sugars and fats in the diet?

-CARBS: 3 major sources in the diet: maltose, lactose, sucrose, and starch (hydrolyzed by surceases in intestine) -FATS: mainly triglycerides

optical deficiency produced by cataracts and the mechanism of correction.

-Cataracts are cloudy areas in the LENS **Important, know that cataracts form in the lens ** -These form when proteins in the lens become denatured, and then begin to coagulate into an opaque mass -When the cloudiness gets bad enough, light transmission into the eye is impaired, and you cant see -Correction= Cataracts are corrected by liquifying the lens and sucking it out of the eye -After the lens is removed, a big portion of the eye's refractive power is gone, so you have to either implant an artificial lens, or use HUGE eyeglass lenses to correct for it.

The Staircase Effect (Treppe)

-Changes in Muscle Strength at the Onset of Contraction -When a muscle begins to contract after a long period of rest, its initial strength of contraction may be as little as one half its strength 10 to 50 muscle twitches later. That is, the strength of con- traction increases to a plateau, a phenomenon called the staircase effect, or treppe.

Channel/pore proteins vs. Carrier proteins

-Channel/pore proteins which provide a watery pathway -Carrier proteins which bind specific substances to be transported.

cones are for _ and rods are for _

-Cones: Color Vision -Rods: Light/dark vision

Describe the role of nondiffusable anions in establishing the membrane potential.

-Due to the inability of many negatively charged molecules (organic phosphates, proteins molecules, sulfate compounds, etc.) to pass through the membranes, the deficit of positive ions (primarily of Potassium) on the inside of membrane leaves an excess of inpermeant negative ions. These are responsible for the negative charge inside the cell. -Contribution of calcium pump- behaves like the Na-K pump and in some cells, it regulated the IC concentration of calcium. -There are also voltage-gated calcium channels (many in smooth muscle and cardiac muscle) involved in AP, etc.

Isometric contraction duration for mammalian, showing a latent period between AP (depolarization) and contraction

-Duration of isometric contractions for different types of mammalian skeletal muscles, showing a latent period between the action potential (depolarization) and muscle contraction. -records of isometric contractions of three types of skeletal muscle: an ocular muscle, which has a duration of isometric contraction of less than 1/40 second; the gastrocnemius muscle, which has a duration of contraction of about 1/15 second; and the soleus muscle, which has a duration of contrac- tion of about 1/3 second. It is interesting that these dura- tions of contraction are adapted to the functions of the respective muscles. Ocular movements must be extremely rapid to maintain fixation of the eyes on specific objects to provide accuracy of vision. The gastrocnemius muscle must contract moderately rapidly to provide sufficient velocity of limb movement for running and jumping, and the soleus muscle is con- cerned principally with slow contraction for continual, long-term support of the body against gravity.

sources of calcium in smooth muscle and two calcium control proteins in smooth muscle?

-EC fluid (major source) -SR is additional source -• Calcium pump removes calcium from the cytosolic/sarcoplasmic fluid. In addition, there may be a calcium- binding protein within the SR called calsequestrin that further lowers IC free calcium

10. State what happens to ICF volume when: a. ECF volume increases; b. ECF volume decreases. c. ECF osmolarity increases; d. ECF osmolarity decreases.

-ECF inc. -> ICF dec. (and vice versa and inversa) -ECF osmolarity increases -> solute outside cell inc. -> hypertonic medium -> H2O goes out -> ICF dec. -decrease in ECF osmolarity -> solute outside dec. -> hypotonic medium -> H2O goes in -> ICF inc. (swelling)

Myofibrils; Actin and Myosin Filaments.

-Each muscle fiber contains several hundred to several thousand myofibrils -Each myofibril is composed of about 1500 adjacent myosin filaments and 3000 actin filaments, which are large polymerized protein molecules that are responsible for the actual muscle contraction. -The thick filaments in the diagrams are myosin, and the thin filaments are actin. -The light bands contain only actin filaments and are called I-bands because they are isotropic to polarized light. The dark bands contain myosin filaments, as well as the ends of the actin filaments where they overlap the myosin, and are called A bands because they are anisotropic to polarized light. Note also the small projections from the sides of the myosin filaments; these are cross-bridges. It is the interaction between these cross-bridges and the actin filaments that causes contraction. -ends of the actin filaments are attached to a so-called Z disc. From this disc, these filaments extend in both directions to interdigitate with the myosin filaments. The Z disc, which itself is composed of filamentous proteins dif- ferent from the actin and myosin filaments, passes crosswise across the myofibril and also crosswise from myofibril to myofibril, attaching the myofibrils to one another all the way across the muscle fiber. -The portion of the myofibril (or of the whole muscle fiber) that lies between two successive Z discs is called a sarcomere.

structure of actin

-Each strand of the double F-actin helix is composed of polymerized G-actin molecules, each having a molecular weight of about 42,000. Attached to each one of the G-actin molecules is one molecule of ADP. It is believed that these ADP molecules are the active sites on the actin filaments with which the cross- bridges of the myosin filaments interact to cause muscle contraction. -actin filament, composed of two helical strands of F-actin molecules and two strands of tropomyosin molecules that fit in the grooves between the actin strands. Attached to one end of each tropomyosin molecule is a troponin complex that is involved in contraction

conclusion of fluoride and gastric mucosa study

-F- in a nearly neutral solution produced no detectable effects on the structure or function of the canine gastric mucosa -HF, not ionic F-, is the form which permeates and damages the mucosa -MFP produced no detectable effects on the structure or function of the gastric mucosa

absorption of fats (most complex)

-Fats- After the triglycerides are broken down, the free fatty acids are carried in micelles to the cell membrane of enterocytes in the microvilli. -The micelles dump the fatty acids into the membrane. -Once inside the cell, the Fatty acids go to the smooth ER, where they are repackaged as triglycerides. -Triglycerides congregate in the Smooth ER and Golgi, and are packaged into CHYLOMICRONS -The chylomicrons travel to the central lacteals, where they enter the lymph and are then dumped into the blood stream.

What is the cause of malignant hyperthermia? How is it activated? What are the treatments?

-Genetic disorder; individuals generally are husky, well-developed, never had problems with muscle function. -Family history usually indicates several family members died "on the operating table" during routine, simple surgery. -Defects in re-uptake of IC Ca++ after use of a depolarizing muscle relaxant like succinylcholine (SC). Also, triggered by some inhalation general anesthetics, (eg., halothane). All muscles begin to contract isometrically; body temp ↑, lactic acid ↑, hyperventilation from heat and acidosis. -Treatment: Stop delivery of potent inhalation anesthesia and/or SC, give dantrolene; ice packs, etc. NOT triggered by nitrous oxide (N2O) (commonly used dental anesthetic).

Golgi tendon organ (GTO)

-Golgi Tendon Organ Helps Control Muscle Tension. -is an encapsulated sensory receptor through which muscle tendon fibers pass. About 10 to 15 muscle fibers are usually con- nected to each Golgi tendon organ, and the organ is stimulated when this small bundle of muscle fibers is "tensed" by contracting or stretching the muscle. -responding intensely when the muscle tension suddenly increases (the dynamic response) but settling down within a fraction of a second to a lower level of steady-state firing that is almost directly proportional to the muscle tension (the static response). Thus, Golgi tendon organs provide the nervous system with instantaneous information on the degree of tension in each small segment of each muscle. -Another likely function of the Golgi tendon reflex is to equalize contractile forces of the separate muscle fibers. That is, those fibers that exert excess tension become inhibited by the reflex, whereas those that exert too little tension become more excited because of absence of reflex inhibition. This spreads the muscle load over all the fibers and prevents damage in isolated areas of a muscle where small numbers of fibers might be overloaded.

significance of fluoride and gastric mucosa study

-HF exposure caused increased blood flow and mucus secretion and, caused massive tissue swelling (edema). Exposure to fluoride did not. -The results show that HF disrupts the "physiologic gastric barrier" and that ionic F does not.

25. Describe the function of the ileocecal valve and sphincter and discuss the controlling factors.

-Ileocecal valve - prevents backflow of fecal contents from the colon into the small intestine -Ileocecal sphincter- thickened muscular coat in the few centimeters of ileum before you get to the valve. Normally remains mildly constricted, slows emptying of the ileum, except after a meal. -controlling factors= -chemical irritation in the cecum (beginning of large intestine) keeps sphincter closed, delays emptying. -lots of volume in the cecum (it is stretched) also delays emptying - watery volume in cecum promoted emptying ...

Sliding Filament Mechanism of Muscle Contraction. (describe the molecular basis of muscle contraction)

-In the relaxed state, the ends of the actin filaments extending from two successive Z discs barely begin to overlap one another. Conversely, in the contracted state, these actin filaments have been pulled inward among the myosin filaments, so that their ends overlap one another to their maximum extent. Also, the Z discs have been pulled by the actin filaments up to the ends of the myosin filaments. Thus, muscle contraction occurs by a sliding filament mechanism. -Inward sliding occurs due to mechanical forces generated by interaction of cross-bridges of myosin filaments with actin filaments. Under resting state, these forces are inhibited, but with AP spread, SR releases Ca2+ions which activate forces between myosin and actin filaments, generating contraction (with ATP cleavage by ATPase activity of myosin head).

smooth muscle contraction without AP; what are some effects of local tissue factors

-Lack of oxygen in the local tissues causes smooth muscle relaxation and, therefore, vasodilatation. -Excess carbon dioxide causes vasodilatation. -Increased hydrogen ion concentration causes vasodilatation. -Adenosine, lactic acid, increased potassium ions, diminished calcium ion concentration, and increased body temperature can all cause local vasodilatation.

job and mechanism of leptin

-Leptin from adipose tissues cross blood-brain barriers to stimulate hypothalamus receptors that inhibit feeding: • leptin decreases secretion of NPY and AGRP. • stimulates release -MSH in POMC neurons, activating melanocortin receptors that inhibit feeding. • stimulates secretion of corticotropin-releasing hormone that decreases food intake. • increases sympathetic NS activity to vasomotor centers to increase metabolic rate and energy expenditure.

starvation conditions

-Marasmus = total starvation in children; failure to thrive; lack of resistance to infections. -Kwashiorkor = protein deficiency; areas of body with no melanin; bands of red to blond hair; patches of white skin; large belly; skinny arms and legs; impaired mental development. -Inanition = Inanition is the exact opposite of obesity. In addition to inanition caused by inadequate availability of food, both psychogenic and hypothalamic abnormalities can on occasion cause greatly decreased feeding. One such state is when a person loses all desire for food and even becomes nauseated by food; as a result, severe inanition occurs. Also, destructive lesions of the hypothalamus, particularly caused by vascular thrombosis, frequently cause a condition called cachexia; the term simply means severe inanition.

10. Define and distinguish between the mixing and propulsive movements of the GI tract.

-Mixing- causes by two things. 1- when a sphincter is closed, and there is peristaltic contraction, the food cant go anywhere, so it is churned up. 2- local constrictive contractions that occur every few centimeters in the gut wall, lasting for a few seconds. These short contractions move the food around -Propulsive (peristaltic) movement- moves the food bolus/chyme down the GI tract by moving a contractile ring forward. (like squeezing on the bottom of a tube of toothpaste and slowly moving your fingers up)

propriospinal fibers

-More than 50% of the nerve fibers that ascend/descend in the spinal cord -made of interneurons that are responsible for interconnecting on or several adjacent segments of the spinal cord -as the sensory fibers enter the cord from the posterior cord roots, they bifurcate and branch both up and down the spinal cord -ascending and descending propriospinal fibers of the cord provide pathways for the multisegmental reflexes

describe basic mechanism for local anesthetics

-Most of these act directly on the activation gates of the sodium chan- nels, making it much more difficult for these gates to open, thereby reducing membrane excitability. When excitability has been reduced so low that the ratio of action potential strength to excitability threshold (called the "safety factor") is reduced below 1.0, nerve impulses fail to pass along the anesthetized nerves. -LA block the initiation and propagation of AP by preventing the voltage-dependent increase in Na+ conductance. Though they exert a variety of nonspecific effects on membrane, as their main action, they are suggested to block sodium channels by physically plugging the transmembrane pore, interacting with residues of the S6 transmembrane helical domain. -Other membrane stabilizers that decrease nerve excitability include high EC calcium ions and various drugs.

25. Describe the secretions of the large intestine.

-Mucous secretion- crypts of lieberkuhn in large intestine do not have enzymes or villi, but simply secrete mucous -Water and electrolytes- large quantities are secreted in response to irritation (diarrhea) Additional info discussed in class: Stimulation of secretion: Ach stimulates, sympathetic stimulation inhibits - Gastrin causes cells to secrete HCl - Histamine is the final common pathway for gastric acid secretion!

three contributions to muscle fatigue

-Muscle fatigue increases in direct proportion to the rate of depletion of muscle glycogen. Therefore, fatigue results mainly from inability of the contractile and metabolic processes of the muscle fibers to continue supplying the same work output. -transmission of the nerve signal through the neuromuscular junction, can diminish after intense prolonged muscle activity, further diminishing muscle contraction. -Interruption of blood flow through contracting muscle leads to almost complete muscle fatigue within minutes.

two types of deafness

-NERVE deafness caused by impairment of the cochlea or auditory nerve, -CONDUCTION deafness caused by impairment of the middle ear mechanisms for transmitting sound into the cochlea, which is called conduction deafness.

DECREASED ABILITY TO ACCOMMOCATE ASSOCIATED WITH AGING

-Near Point: The minimum distance at which the object can be seen clearly. -Amplitude (D): The ability to focus clearly on objects at near distances measured in diopters. -Diopter (D): A diopter is the reciprocal of the len's focal length measured in meters.

Myopia and how its corrected

-Nearsightedness: Light rays focus in front of the retina. -corrected with biconcave lenses, which causes light rays to diverge slightly before striking the eye.

11. State the nephron segment from which the bulk of bicarbonate is reabsorbed; state the nephron segment in which the greatest pH change normally occurs.

-Nephron segment that reabsorbs the most bicarbonate= PROXIMAL TUBULE - Nephron segment with greatest pH change- DISTAL NEPHRON (late distal tubule and collecting duct -This secretion only accounts for 5% of the total secretion, but changes the pH the most! (because the H+ ions are not being used up for bicarbonate reabsorption!

describe the Relation of muscle length to tension in the muscle both before and during muscle contraction.

-Note in Figure 6-9 that when the muscle is at its normal resting length, which is at a sarcomere length of about 2 micrometers, it contracts upon activation with the approximate maximum force of contraction. However, the increase in tension that occurs during contraction, called active tension, decreases as the muscle is stretched beyond its normal length—that is, to a sarcomere length greater than about 2.2 microm- eters. This is demonstrated by the decreased length of the arrow in the figure at greater than normal muscle length.

8. List the major spinal origins of the SNS and PNS innervations of the gut.

-Parasympathetic innervation origin- Most of the GI parasymp. stimulation is from the VAGUS nerve. (concentrated at esophagus, pancreas, stomach, with little innervation to the intestines). The last parts (sigmoidal, rectal, anal segments) of the lg. intestine are innervated by S2-S4 - Sympathetic innervation- spinal origin of SNS fibers to the gut= T5-L2. Major ganglion involved = celiac ganglion and mesenteric ganglia.

9. State the major effects produced by stimulation of the SNS and PNS pathways to the gut.

-Parasympathetic- increases activity of enteric nervous system. This enhances most GI activity. -Sympathetic- generally inhibits activity of the GI tract, by the inhibitory effect of NE on the neurons of the enteric nervous system.

9. State the major effects produced by stimulation of the SNS and PNS pathways to the gut.

-Parasympathetic- increases activity of enteric nervous system. This enhances most GI activity. -Sympathetic- generally inhibits activity of the GI tract, by the inhibitory effect of NE on the neurons of the enteric nervous system.

protein digestion order of enzyme action

-Pepsin: (stomach) ​- trypsin, chymotrypsin: (small intestine) -carboxtpeptidase, and proelastase -peptidases (from the enterocytes in small intestinal villi of the brush border -AA's are absorbed as di - tri - peptides

3. List the major buffer systems of the human body including both the physiologic (functional) and chemical (passive) systems.

-Physiologic buffer system- The BICARBONATE system (will be described in following BO's (homeostatically regulated) -Chemical buffer systems- these buffers work instantly, but can be used up. -Protein- Proteins in the cells (Hemoglobin, for example) and proteins in plasma are chemical buffers. Remember that most proteins at physiologic pH (7.4) have a negative charge. This can attract H+ - Phosphate buffer system (important in urine); Phosphate (PO4) has a charge of -3. So it can accept up to 3 H+'s - Ammonia buffer system (also important in urine) Ammonia can accept and release one H+ ion

Give an example of a physiologic mechanism which operates at the molecular level; one which operates at the cellular level and one which operates at the "system" level.

-Physiological mechanisms in the body operate collaboratively at different levels: molecular, cellular, tissue, organ and system levels. -

12. Why does severe circulatory shock sometimes progress to an irreversible stage? Factors?

-Positive feedbacks further depress CO in shock causing it to become progressive (vicious circle of CV deterioration) a. Cardiac depression: When arterial P falls low enough, this will decrease coronary blood flow and weaken cardiac muscle. b. Vasomotor failure: Diminished blood flow to brain's vasomotor center make it inactive. c. Blockage of very small vessels (slugged blood) d. Toxin release by ischemic tissue leads to cardiac depression, generalized cellular deterioration, and tissue necrosis (eg., endotoxin from bacteria). e. Generalized cellular deterioration: Occurs with severe cases; liver is especially affected, others being the lungs and the heart. Cellular effects include: • Impairment of active transport systems and mitochondrial activity, split opening of lysosomes, depression of cellular nutrient metabolism and acidosis (poor delivery of oxygen to tissue increases anaerobic glycolysis, and lactic acid accumulation) .

3. What does the QRS complex of the electrocardiogram represent? What does the T-wave of the electrocardiogram represent?

-QRS complex appears prior to ventricular contraction, which remains until after repolarization or end of T wave (a prolonged wave); -T wave is the end of monophasic action potential

glycolysis of muscle glycogen as energy for contraction; what is the twofold importance of this glycolysis mechanism

-Rapid enzymatic breakdown of the glyco- gen to pyruvic acid and lactic acid liberates energy that is used to convert ADP to ATP; the ATP can then be used directly to energize additional muscle contraction and also to re-form the stores of phosphocreatine. 1)can occur anaerobically 2)rate of formation of ATP by the glycolytic process is about 2.5 times as rapid as ATP formation in response to cellular foodstuffs reacting with oxygen. However, so many end products of glycolysis accumulate in the muscle cells that glycolysis also loses its capability to sustain maximum muscle contraction after about 1 minute.

2. What is the approximate inherent rate of the S-A node, the A-V node in the ventricular muscle?

-SA node - normal rate of the sinus node of 70 to 80 times per minute. -A-V nodal fibers, when not stimulated from some outside source, discharge at an intrinsic rhyth- mical rate of 40 to 60 times per minute,

molecular or ionic substances responsible for the taste of:bitter. and the region of the tongue where they are tasted (p. 677).

-SOUR- hydrogen ions; intensity of the taste sensation is approximately proportional to the logarithm of the hydrogen ion concentration. -SALTY- ionized salts/monovalent cations (Na+, K+) -SWEET- (lots of things)- sugars, glycols, alcohols, aldehydes, ketones, etc. Mainly, the sweet taste is usually associated with a series of hydroxyl groups; the only inorganic substances that elicit the sweet taste are certain salts of lead and beryllium. -BITTER- long chain organic substances and alkaloids (these are usually toxic, so the bitter taste is probably a protective mechanism) -UMAMI - monosodium glutamate Regions of the Tongue: sweet and salty- tip of the tongue, sour- lateral sides of the tongue, bitter- posterior tongue and soft palate

An especially important function of the stretch reflex is its ability to prevent oscillation or jerkiness of body movements. this is a damping, or smoothing, function,

-Signals from the spinal cord are often transmitted to a muscle in an unsmooth form -when the muscle spindle apparatus is not functioning satisfactorily, the muscle contraction is jerky during the course of such a signal. -This effect can also be called a signal averaging function of the muscle spindle reflex.

which has a more elaborate SR/t-tubule system - skeletal muscle or smooth muscle?

-Skeletal muscle has the most elaborate development of its sacroplasmic reticulum (SR)/T-tubule for storage of intracellular calcium. It requires no extracellular (EC) calcium for contraction. -Cardiac muscle has the next most elaborate sarcoplasmic/T- tubule system for storage of intracellular calcium. -Smooth muscle has the least developed sacroplasmic reticulum and requires extracellular calcium diffusion into the cell for contraction. This is one reason why it takes so long for smooth muscles to contract. This inward diffusion of calcium is also responsible for the plateau phase of the smooth muscle action potential seen in visceral smooth muscle (but not so in multi-unit smooth muscle).

Comparison of Smooth Muscle Contraction and Skeletal Muscle Contraction

-Slow Cycling of the Myosin Cross-Bridges (attach -> release -> attach); (cross-bridge heads have far less ATPase activity than in skeletal muscle is possible reason) -Yet the fraction of time that the cross-bridges remain attached to the actin filaments, which is a major factor that determines the force of contraction, is believed to be greatly increased in smooth muscle. -Energy Required to Sustain Smooth Muscle Contraction is much less than in skeletal muscle; more economical though as only one molecule of ATP is required for each cycle, regardless of its duration. -Slowness of Onset of Contraction and Relaxation of the Total Smooth Muscle Tissue. (contraction takes 30x longer than one skeletal muscle contraction) -As smooth muscle has no sarcomeric organization, it has no length-tension diagram as seen in SKM. SM can shorten 2/3 of its original length, greater than SKM. -6. Latch mechanism enables smooth muscle to hold contractions for long periods of time with little use of ATP/energy. Under this condition, contraction is maintained after SM activation ceases.

what causes spontaneous generation of AP in single-unit smooth muscle?

-Slow wave potentials (above threshold) -stretch

6. Describe the effects of the autonomic nervous system on cardiac conduction and rhythmicity.

-Stimulation of the parasympathetic nerves to the heart (the vagi) causes the hormone acetylcholine to be released at the vagal endings. This hormone has two major effects on the heart. First, it decreases the rate of rhythm of the sinus node, and second, it decreases the excitability of the A-V junctional fibers between the atrial musculature and the A-V node, thereby slowing transmission of the cardiac impulse into the ventricles. -sympathetic stimulation causes essentially the opposite effects on the heart to those caused by vagal stimulation, as follows: First, it increases the rate of sinus nodal discharge. Second, it increases the rate of conduction as well as the level of excitability in all portions of the heart. Third, it increases greatly the force of contraction of all the cardiac musculature, both atrial and ventricular. (Stimulation of the sympathetic nerves releases the hormone norepi- nephrine at the sympathetic nerve endings.)

Clinical utility of muscle jerks

-Tapping on the patellar tendon at the knee stretches spindles in the quadriceps and elicits a reflex contraction of that muscle group (stretch reflex), producing a knee jerk. -This tests the degree of facilitation of spinal cord centers from higher centers. - Too much higher center facilitation leads to exaggerated reflexes. - Too little leads to depressed reflexes. - Lesions of motor cortex tend to cause exaggerated jerk reflexes on opposite side due to loss of corticofugal influence.

tropomyosin molecule

-These molecules are wrapped spirally around the sides of the F-actin helix -In the resting state, the tropomyosin molecules lie on top of the active sites of the actin strands, so that attraction cannot occur between the actin and myosin filaments to cause contraction.

Re-establishing Sodium and Potassium Ionic Gradients After Action Potentials Are Completed

-This is achieved by action of the Na+-K+ pump in the same way as described previously in the chapter for the original establishment of the resting potential. That is, sodium ions that have diffused to the interior of the cell during the action potentials and potassium ions that have diffused to the exterior must be returned to their original state by the Na+-K+ pump. Because this pump requires energy for operation, this "recharging" of the nerve fiber is an active metabolic process, using energy derived from the adenosine triphosphate (ATP) energy system of the cell.

Describe the significance of rhythmic action potentials and their relationship to potassium conductance.

-This shows that toward the end of each action potential, and continuing for a short period thereafter, the membrane becomes excessively permeable to potassium ions. -The excessive outflow of potassium ions carries tremendous numbers of positive charges to the outside of the membrane, leaving inside the fiber considerably more negativity than would otherwise occur. This continues for nearly a second after the preceding action potential is over, thus drawing the membrane potential nearer to the potassium Nernst potential. This is a state called hyperpolarization, As long as this state exists, self-re-excitation will not occur. But the excess potassium conductance (and the state of hyperpolarization) gradually disappears, as shown after each action potential is completed in the figure, thereby allowing the membrane potential again to increase up to the threshold for excitation. Then, suddenly, a new action potential results, and the process occurs again and again.

16. List the major stages of swallowing and describe the main features of each.

-Voluntary stage= food is voluntarily pushed back into the throat by the tongue pushing up and back against the palate. When the food moves beyond this point, swallowing is automatic, and can usually not be stopped. -Pharyngeal stage= "swallowing receptor areas" are stimulated when food enters the pharynx, causes a series of contractions 1-soft palate pulled up, prevents food entering nasal cavity 2- palatopharyngeal folds move to form a slit that well chewed food can move through 3- larynx is moved up and forward, moving the epiglottis with it, which prevent food from going down your trachea 4- pharyngeosophageal (hyperpharyngeal) sphincter relaxes, allowing food to move into the esophagus 5- muscular wall of pharynx contracts, beginning peristaltic movement

7. What are the central venous pressure waves (i.e. right atrial pressure changes) in each cardiac cycle?

-a-wave is caused by atrial contraction. Ordinarily, the right atrial pressure increases 4 to 6 mm Hg during atrial contraction, and the left atrial pressure increases about 7 to 8 mm Hg. -c wave occurs when the ventricles begin to contract; it is caused partly by slight backflow of blood into the atria at the onset of ventricular contraction but mainly by bulging of the A-V valves backward toward the atria because of increasing pressure in the ventricles. -v wave occurs toward the end of ventricular contraction; it results from slow flow of blood into the atria from the veins while the A-V valves are closed during ventricular contraction. Then, when ventricular contraction is over, the A-V valves open, allowing this stored atrial blood to flow rapidly into the ventricles and causing the v wave to disappear.

absorption of AA's

-absorbed mainly as di- tri-peptides -​ energy also supplied by Na co-transport -specific for L-stereoisomers (there are no D-isomers in proteins) -​specific carrier molecules exist for specific classes of peptides

the Ach receptor at NMJ is the nicotinic N(M) type, which is selectively stimulated or blocked only by certain cholinergic drugs; what are three actions a cholinergic drug to could take on Ach-mediated responses?

-acetylcholine receptor activators -receptor blockers -Ach release inhibitors

what type of transport proteins are the acetylcholine receptors and in what part of the motor-end plate are acetylcholine receptors located?

-acetylcholine-gated ion channels -in the muscle fiber membrane near the mouths of the subneural clefts lying immediately below the dense bar areas, where the acetylcholine is emptied into the synaptic space by exocytosis

what enzyme is used to breakdown acetylcholine after it has been released, where would you find it? what are the products and what happens to them?

-acetylcholinesterase in the synaptic space -Ach is broken down into acetate ion and choline, and the choline is reabsorbed actively into the neural terminal to be reused to form new acetylcholine.

actin filament is composed of what three protein components

-actin -tropomyosin -troponin

Describe the all-or-none principle.

-action potential elicited at any one point on an excitable membrane usually excites adjacent portions of the membrane, resulting in propagation of the action potential along the membrane. -That is, positive electrical charges are carried by the inward-diffusing sodium ions through the depolarized membrane and then for several millimeters in both directions along the core of the axon; the sodium channels in these new areas immediately open and the AP spreads

propagation of AP

-action potential elicited at any one point on an excitable membrane usually excites adjacent portions of the membrane, resulting in propagation of the action potential along the membrane. -That is, positive electrical charges are carried by the inward-diffusing sodium ions through the depolarized membrane and then for several millimeters in both directions along the core of the axon; the sodium channels in these new areas immediately open and the AP spreads

Describe the direction of propagation of an impulse along an excitable membrane and the mechanism of propagation.

-an excitable membrane has no single direction of propagation, but the action potential travels in all directions away from the stimulus—even along all branches of a nerve fiber—until the entire membrane has become depolarized.

Temporal summation (frequency summation)

-another means of transmitting signals with increased frequency of impulse thus increasing the strength of signals in each fiber. -The effect is generated by a single neuron as a way of achieving action potential. Summation occurs when the time constant is sufficiently long, a fraction of a second, and the frequency of rises in potential are high enough that a rise in potential begins before a previous one ends. -The amplitude of the previous potential at the point where the second begins will algebraically summate, generating a potential that is overall larger than the individual potentials. This allows the potential to reach the threshold to generate an action potential.

name 3 abnormal pressure pulse contours

-aortic valve stenosis, the diameter of the valve opening is reduced markedly and the aortic pressure pulse is greatly decreased due to diminished blood flow via the stenotic valve. -With patent ductus arteriosus, some of the blood pumped into the aorta flows immediately backward through the open ductus into the pulmonary artery and lung vasculature, thereby permitting the diastolic pressure to fall very low before the next heartbeat. -With aortic regurgitation, the aortic valve is absent or functions poorly. After each heartbeat, the blood that pumped into the aorta flows immediately backward into the left ventricle (during diastole), causing the aortic pressure to fall very low between heartbeats (increasing pulse pressure). There is also no incisura in the aortic pulse contour since there is no aortic valve (ie., to close).

5. Describe and give examples of abnormalities which may be detected using an ECG.

-arrythmias like tachy- and brady-cardia -S-A node block

6. What types of abnormalities may be diagnosed using a standard three lead electrocardiogram?

-arrythmias like tachy- and brady-cardia -S-A node block -atrial premature beat -premature ventricular contractions -ventricular fibrillation -atrial flutter

2. Describe the percent of cardiac output that flows to various organs. Which tissues have the highest and lowest blood flow in ml/min/100 gm?

-bone and skin have lowest blood flow -kidneys and adrenal glands have hughes

why do Ach and norepinephrine have different responses in smooth muscle in different organs?

-both acetylcholine and norepinephrine excite or inhibit smooth muscle by first binding with a receptor protein on the surface of the muscle cell membrane. Some of the receptor proteins are excitatory receptors, whereas others are inhibitory receptors. Thus, the type of receptor determines whether the smooth muscle is inhibited or excited and also determines which of the two transmitters, acetylcholine or norepinephrine, is effective in causing the excitation or inhibition.

compare or contrast the effects of curari-form and Botulinum toxin on end plate potentials; some mechanisms or different? what are they?

-both cause weakened end plate potential and lead to AP loss -curari-form drugs block nicotinic Ach receptors by competing for binding sites; reduces amplitude of end plate potential, therefore, no AP (or contraction). -botulinum toxin decreases release of Ach from nerve terminals which results in insufficient stimulus to innate an AP.

which type of venous wave occurs when the ventricles begin to contract; it is caused partly by slight backflow of blood into the atria at the onset of ventricular contraction but mainly by bulging of the A-V valves backward toward the atria because of increasing pressure in the ventricles.

-c wave

The presence of calcium on membranes is necessary to prevent excess sodium permeability. What is the effect of hypocalcemia on nerve and muscle membrane potentials?

-calcium ions are said to be a membrane-stabilizing factor -a high extracellular fluid calcium ion concentration decreases membrane permeability to sodium ions and simultaneously reduces excitability.

two mechanisms function to remove calcium from among the myofibrils in order to stop contraction

-calcium pump - continually active pump located in the walls of the SR pumps calcium ions away from the myofibrils back into the sarcoplasmic tubules. -calsequestrin protein inside the SR can bind up to 40 times more calcium.

two mechanisms for calcium removal after depolarization

-calcium pump in sarcoplasmic reticulum -sodium/calcium exchanger in cell membrane of cardiac fiber (coupled with sodium/potassium ATPase; mechanism is secondary counter-transport where potential is generated by one that runs the other)

Describe the basic apparatus for recording membrane potentials and compare electrode arrangement for recording monophasic and biphasic action potentials.

-cathode ray oscilloscope -The cathode ray tube itself is composed basically of an electron gun and a fluorescent screen against which electrons are fired. Where the electrons hit the screen surface, the fluorescent material glows. If the electron beam is moved across the screen, the spot of glowing light also moves and draws a fluorescent line on the screen. -In addition to the electron gun and fluorescent surface, the cathode ray tube is provided with two sets of electrically charged plates—one set positioned on the two sides of the electron beam, and the other set posi- tioned above and below. Appropriate electronic control circuits change the voltage on these plates so that the electron beam can be bent up or down in response to electrical signals coming from recording electrodes on nerves. The beam of electrons also is swept horizontally across the screen at a constant time rate by an internal electronic circuit of the oscilloscope. This gives the record shown on the face of the cathode ray tube in the figure, giving a time base horizontally and voltage changes from the nerve electrodes shown vertically. Note at the left end of the record a small stimulus arti- fact caused by the electrical stimulus used to elicit the nerve action potential. Then further to the right is the recorded action potential itself.

Describe the deficit that is responsible for myasthenia gravis? How is it treated? What are the oral manifestations?

-causes muscle paralysis because of inability of the NMJ's to transmit enough signals from the nerve fibers to the muscle fibers. -antibodies that attack the Achgated sodium ion transport proteins have been demonstrated in the blood of most patients with myasthenia gravis. -believed that myasthenia gravis is an autoimmune disease in which the patients have developed immunity against their own Ach-activated ion channels. -The disease usually can be ameliorated for several hours by administering neostigmine or some other anticholinesterase drug, which allows larger than normal amounts of acetylcholine to accu- mulate in the synaptic space. Within minutes, some of these paralyzed people can begin to function almost normally, until a new dose of neostigmine is required a few hours later.

11. State what is meant when a nerve fiber is called: a. cholinergic; b. adrenergic.

-cholinergic; sympathetic fibers that release Ach at their target cell -adrenergic. release NE at their target cell

5. Describe the indirect (ausculatory) method of measuring blood pressure. As the pressure cuff is deflated, what does the first sound indicate?

-clinicians usually determine blood pressure (systolic and diastolic) indirectly by the auscultatory method. -Placing a stethoscope over the antecubital artery -inflate cuff past 115 -When the cuff pressure is released and falls below systolic pressure (point B in figure), one begins to hear tapping sounds indicating systolic pressure. -As the pressure is lowered still more, the sounds change in quality, and when the pressure in the cuff falls near diastolic pressure, the sounds suddenly change to a muffled quality (point C in figure). The pressure indicated on the manometer during this time is taken as a diastolic pressure.

secondary active transport is observed in two different transporter proteins

-co-transport (co-porters) - substance is transported in the same direction as the "driver" ion (eg., Na+). Examples: transport of glucose, HCO3-. -counter-transport (anti-porters) - substance is transported in the opposite direction as the "driver" ion (Na+). Examples: transport of Ca2+, H+, Cl-.

drugs that block transmission at the neuromuscular junction by blocking the receptor by competing for binding site

-curari-form drugs such as D-turbocurarine compete with Ach for receptor sites thereby blocking its action. (Block nicotinic ACh receptors by competing for binding site; Reduces amplitude of end plate potential, therefore, no AP (or contraction). - a similar drug is succinylcholine, another neuromuscular blocking agent

glaucoma

-degenerative disease in which there is a gradual loss of retinal ganglia cells. -Increased intraocular pressure (IOP) is NOT the cause glaucoma as is commonly believed. About 25% of glaucoma patients have normal IOP. -High IOP is due to (a) decreased fluid flow through the trabeculae (open-angle glaucoma) or (b) forward movement of the iris which can obliterate the iris-corneal angle (closed-angle glaucoma).

location and essential function of muscle spindles?

-distributed throughout the belly of muscle -sense changes in muscle length -sense rate of change in length

what causes the positive after-potential (after-hyperpolarization) on an action potential waveform? describe the ion movements which account for it.

-due to prolonged opening of the potassium channels, permitting too much outward diffusion of potassium and hence a membrane potential that is too negative.

The gamma motor neurons are of 2 types based on the type of intrafusal fibers they innervate:

-dynamic (distribute to intrafusal nuclear bag fibers) --static (distribute to intrafusal nuclear chain fibers), (causes dynamic or static responses, respectively, upon stimulation.)

the myotatic reflex/muscle spindle stretch reflex can be divided into two components:

-dynamic stretch reflex is elicited by the potent dynamic signal transmitted from the primary sensory endings of the muscle spindles, caused by rapid stretch or unstretch. That is, when a muscle is suddenly stretched or unstretched, a strong signal is transmitted to the spinal cord; this causes an instantaneous strong reflex contraction (or decrease in contraction) of the same muscle from which the signal originated. Thus, the reflex functions to oppose sudden changes in muscle length. and is over within a fraction of a second after the muscle has been stretched/un-stretched. -then a weaker static stretch reflex continues for a prolonged period there- after. This reflex is elicited by the continuous static receptor signals transmitted by both primary and secondary endings. The importance of the static stretch reflex is that it causes the degree of muscle contraction to remain reasonably constant, except when the person's nervous system specifically wills otherwise.

two most important characteristics of multi-unit smooth muscle?

-each fiber can contract independently of the others -their control is exerted mainly by nerve signals.

12. Define edema and list the four major causes of extracellular edema.

-edema is the presence of excess fluid in extra or intracellular compartments -causes of ICF edema: failure of membrane pumps and inflammation -causes of ECF edema - capillary filtration -1. increased capillary pressure -2. decreased plasma proteins -3. increased capillary permeability -4. blockage of lymph return

which type of innervation has a greater effect on the heart

-effect of parasympathetic is lower than sympathetic -sympathetic is more because of denser innervation

What is facilitated diffusion? Active Transport? Give examples of each.

-facilitated diffusion (carrier-mediated) - uses carrier protein in membrane but doesn't use energy) - involves conformational change - diffusion rate approaches maximum (Vmax) - examples: glucose and most AA transport -active transport (carrier-mediated, energy-dependent) - uses carrier protein and ATP

1. Why is the heart regarded as a functional syncytium?

-group of cardiac cells known as heart functions as unit -2 different syncytiums in heart: atrial and ventricular

loss of higher vs lower frequencies

-hearing loss for the HIGHER frequencies: If the nerve is still functional but degenerating -greater loss for the LOWER frequencies: if the cochlea and nerve are still intact but the ossicular system has been destroyed or ankylosed ("frozen" in place by fibrous tissue or calcification), sound waves can still be conducted into the cochlea by means of bone conduction (such as conduction of sounds from the butt of a vibrating tuning fork applied directly to the skull).

loss of higher vs lower frequencies

-hearing loss for the HIGHER frequencies: If the nerve is still functional but degenerating -greater loss for the LOWER frequencies: if the cochlea and nerve are still intact but the ossicular system has been destroyed or ankylosed ("frozen" in place by fibrous tissue or calcification), sound waves can still be conducted into the cochlea by means of bone conduction (such as conduction of sounds from the butt of a vibrating tuning fork applied directly to the skull). The audiogram shows a

Relation of Velocity of Contraction to Load

-higher load -> lower velocity -To move large loads, one must slow down contraction velocity to provide every opportunity for actin and myosin to interact to produce needed force. That is, during high velocity most of the interactions between actin and myosin do not occur due to insufficient time or opportunity for such interactions.

location and function of calsequestrin

-in SR -calsequestrin binds Ca2+, further depleting the ion from the cytosol/myofibrils.

11. What effect does gravity have on venous pressure? How do venous valves modify it?

-in an adult standing absolutely still, the pressure in the veins of the feet is ~ 90 mm Hg because of the gravitational weight of the blood in the veins between the heart and the feet. At other levels of the body, the venous pressures are between 0 and 90 mm Hg. -In a person standing upright, the neck veins collapse all the way to the skull due to atmospheric pressure on the outside of the neck, causing the pressure in the veins to remain at zero. Any tendency for the pressure to rise above this level opens the veins and allows the pressure to fall back to zero because of flow of the blood. The tendency for the neck vein pressure to fall below zero collapses the veins further, still increasing their resistance and returning the pressure to zero. -Besides its effects in the veins, gravitational factor also affects pressures in the peripheral arteries and capillaries. A standing person with a mean arterial pressure of 100 mm Hg at the level of the heart has an arterial pressure in the feet of ~ 190 mm Hg. Thus, arterial pressure of 100 mm Hg is the pressure at the gravitational level of the heart, but not necessarily elsewhere in the arterial vessels.

smooth muscle is innervated by what type of nerve fibers

-innervated by autonomic nerve fibers (skeletal innervated by motor/somatic nerve fibers)

17. Define isotonic, isosmolar, hypotonic and hypertonic.

-isotonic - doesn't cause swelling or shrinkage -isomolar - fluid outside the cell that has the same osmolarity as fluid on the inside of the cell -ALL ISOTONIC SOLUTIONS ARE ISOMOLAR but not all isomolar solutions are isotonic

7. List four factors that can influence the rate of diffusion of a substance through the capillary membrane.

-lipid solubility vs. H2O solubility (lipid soluble stuff diffuses directly without the use of pores) -molecular size = smaller -> faster -size of concentration gradient at the moment -# of pores for H2O soluble solutes and their diameter

1. Describe the three major types of control of blood flow.

-local control - Local tissues autoregulate blood flow in response to their individual needs (acute and long term) -humoral control -nervous control

24. List the membrane-bound enzymes of the small intestine, their major actions and their overall contribution to the digestion of foods.

-located in enterocytes of mucosa- cover villi -peptidases- split small peptides -sucrase, maltase, isomaltase, and lactase- split carbohydrates -lipase- split neutral fat into glycerol and fatty acid

where are Golgi tendon organs located and what is their function?

-located in tendons -give information about tension

Calcium pump

-located in the SR -pumps Ca2+ ions away from the myofibrils back into the SR tubules. -Also, in the SR, calsequestrin binds Ca2+, further depleting the ion from the cytosol/myofibrils.

Renshaw cells

-located in the anterior horns of the spinal cord -in close association with the motor neurons -inhibitory cells that trans- mit inhibitory signals to the surrounding motor neurons. Thus, stimulation of each motor neuron tends to inhibit adjacent motor neurons, an effect called lateral inhibition. -This effect is important for the following major reason: The motor system uses this lateral inhibition to focus, or sharpen, its signals in the same way that the sensory system uses the same principle—that is, to allow unabated transmission of the primary signal in the desired direction while suppressing the tendency for signals to spread laterally.

where are the gamma motor neurons located and what is their physiological role?

-located in the spinal cord anterior horns. -transmit impulses through much smaller (than the alpha motor neurons) type A gamma (Ag) motor nerve fibers, averaging 5 micrometers in diameter, which go to small, special skeletal muscle fibers called intrafusal fibers. These fibers constitute the middle of the muscle spindle, which helps control basic muscle "tone,"

Unitary Smooth Muscle (does not mean single muscle fibers.)

-mass of hundreds to thousands of smooth muscle fibers that contract together as a single unit. -arranged in sheets or bundles -cell membranes adherent to one another at multiple points so that force generated in one muscle fiber can be transmitted to the next. - cell membranes are joined by many gap junctions through which ions and AP can travel

drugs that stimulate the muscle fiber by acetylcholine-like action

-methacholine (may not be effective at NMJ) -carbachol -nicotine (unlike acetylcholine, these drugs are not rapidly destroyed by cholinesterase)

Describe the morphology of a nerve trunk identifying its various components and relate these to certain functional characteristics.

-myelinated (Schwann cells, gaps->nodes of rangier) -axonal membrane is site of AP -

what charge does the mouth of the acetylcholine channel possess and what function does it have?

-negative -keeps negative ions out like chloride

Sensory signal enters the spinal cord via the sensory (posterior) roots and thereafter travels to 2 separate destinations:

-one branch synapses on cord gray matter with the anterior horn motor neurons, interneurons or sensory relay neurons; might elicit local segmental reflexes, etc. -second branch transmitting signals to higher levels of the nervous system (in cord itself, brain stem, or cerebral cortex).

compare the types of innervation in heart

-parasympathetic innervation affects mainly the aorta and the rate of contraction (mainly depresses chronotropic action of heart) -sympathetic affects the rate of contraction as well as the force (chronotropic and inotropic)

14. State which part of the bicarbonate buffer system is regulated by the pulmonary system; by the renal system.

-part of Bicarbonate system regulated by pulmonary (lungs)= CO¬2 concentration - part of Bicarbonate system regulated by renal (kidneys) = H+ concentration

efficiency of muscle contraction

-percentage of energy input that is converted into work instead of heat. -The percentage of the input energy to muscle (the chemical energy in nutrients) that can be converted into work, even under the best conditions, is less than 25 per cent, with the remainder becoming heat. The reason for this low efficiency is that about one half of the energy in foodstuffs is lost during the formation of ATP, and even then, only 40 to 45 per cent of the energy in the ATP itself can later be converted into work.

Factors affecting net rate of diffusion

-permeability of membrane -concentration gradient (higher concentration means higher diffusion) -pressure difference across membrane (from high to low) -in case of ions, electrical potential difference

sources of energy for muscle contraction

-phosphocreatine (quick boost) -glycolysis of muscle glycogen to replenish both ATP and phosphocreatine -oxidative metabolism

5. Of the structures listed in item 5, which is the one most responsible for determining blood flow rate and pressure in the: a. preferential channels; b. true capillaries?

-preferential channels: shunts blood away from true capillaries, large -true capillaries: more rapid

Accommodation

-process by which the curvature of the lens in increased (more convex) so that near objects can be seen clearly. -Accommodation is strictly under PNS control. -The inability to accommodate is called PRESBYOPIA.

what is the direction of transport of that the SR calcium pumps?

-pumps Ca2+ ions away from the myofibrils back into the SR tubules.

15. Describe the general nature of effector cell receptors for the ANS and, upon stimulation, what changes can occur to account for the observed effects.

-receptors- neurotransmitters bind to receptors on the cells that it wants to effect receptor= bound to outside of cell membrane, part of a protein that goes through the membrane into the cell -Receptor/neurotransmitter binding is specific -result of binding= altered permeability of the cell to certain ions, or changes in the activity of certain enzymes -remembr all the types of receptors we talked about in biochem. These receptors follow the same pattern of action -He briefly described two types of adrenergic receptors (respond to EPI and NE), alpha and beta receptors. Depending on the type of receptor present on the cell, the cell will react differently to these neurotransmitters.

Define homeostasis. Give three examples of homeostatic mechanisms and how they achieve homeostasis.

-regulation of O2 and CO2 in EC fluid: role of hemoglobin (respiratory stimulation by elevated or excess CO2) -regulation of arteriole blood pressure (baroreceptors) -regulation of blood glucose

8. What 2 factors regulate central venous pressure? What is its normal value?

-relationship to right atrial pressure (central venous pressure) and peripheral venous pressure: Blood from the systemic veins flows into the right atrium; thus, the pressure in the right atrium is called the central venous pressure. The right atrial pressure is regulated by a balance between the heart's ability to pump blood out of the right atrium and ventricle and the tendency for blood to flow from the peripheral vessels into the right atrium. During vigorous pumping of the right heart, the right atrial pressure decreases, while weakness of the heart increases the right atrial pressure. Effects that cause rapid inflow of blood into the right atrium also elevate the right atrial pressure. Common causes that can increase venous return and elevate right atrial pressure include: (a) increased blood volume, (b) increased large vessel tone in the body with increased peripheral venous pressures, and (c) dilatation of arterioles (decreasing peripheral resistance and allowing rapid flow of blood from arteries into veins). The factors regulating right atrial pressure also contribute to regulation of cardiac output since the amount of blood pumped by the heart depends upon both the ability of the heart to pump and the tendency for blood to flow into the heart from peripheral vessels. The right atrial pressure normally is ~ 0 mm Hg (= atmospheric pressure, the lower limit being -3 to -5 mm Hg) but it can increase to 20-30 mm Hg under abnormal conditions (eg., serious heart failure or after massive transfusion- increasing total blood volume and driving excessive quantities of blood into the heart from the peripheral vessels).

If local anesthetics like cocaine or lidocaine block the opening of sodium channels in nerve membranes, what would they do to the resting membrane potential? What would they do to the action potential?

-resting membrane potential (and threshold potential) are not changed -action potential is virtually impossible to achieve due to the lack of Na influx caused by the anesthetic

Describe the morphology of a myelinated nerve fiber and the functional significance of the Schwann cell.

-schwann cells function to insulate nerve fibers -The functional significance of the Schwann cell is at least to form myelin, to support the axon and to serves as a tube for nerve regeneration in the event of damage or degeneration. -The central core of the fiber is the axon, and the membrane of the axon is the membrane that actually conducts the action potential. The axon is filled in its center with axoplasm, which is a viscid intracellular fluid. Surrounding the axon is a myelin sheath that is often much thicker than the axon itself. About once every 1 to 3 milli- meters along the length of the myelin sheath is a node of Ranvier (2-3 micrometers in length) -The membrane of a Schwann cell first envelops the axon. Then the Schwann cell rotates around the axon many times, laying down multiple layers of Schwann cell membrane containing the lipid substance sphingomyelin.

initiation of contraction: excitation-contraction coupling in the muscle

-showing (1) an action potential (AP) that causes release of calcium ions from the sarcoplasmic reticulum and then (2) re-uptake of the calcium ions by a calcium pump

which does not require extracellular calcium - skeletal muscle, smooth muscle or cardiac muscle?

-skeletal muscle requires no extracellular calcium

The opened acetylcholine channel has a diameter of about 0.65 nanometer, which is large enough to allow the important positive ions—to move easily through the opening.

-sodium (Na+), -potassium (K+) -calcium (Ca++) Conversely, negative ions, such as chloride ions, do not pass through because of strong negative charges in the mouth of the channel that repel these negative ions.

what substance gives Schwann cells their insulation capabilities? what type of macromolecule is it?

-sphingomyelin -lipid

pepsin

-stomach entedopeptase, -pH optimum 2-3 -begins hydrolysis of peptide bonds -cleaves proteins next to aromatic AA's (Tyr, Trp, Phenylalanine)

4. List the major structures of a typical capillary bed.

-supplied by arterioles -drained by venules -exception is glomerulus which is both drained and supplied by arterioles

20. Define sympathetic tone and parasympathetic tone. Describe their functional significance.

-sympathetic/parasympathetic tone= the basal level of activity that these fibers always have. Tone is very important to the ANS function -sympathetic tone- keeps the arterioles partially contracted at all times. This way, changes in sympathetic stimulation can cause arterioles to contract more, or to relax (if the normal tone becomes inhibited) Without tone, we could only cause vasocontraction, never vasodilation, by changing the action of the SNS - parasympathetic tone- adds to the normal function of the GI tract. Without this tone, serious constipation results

unitary smooth muscle is aka x 2

-syncytial smooth muscle because of its syncytial interconnections among fibers. It is also called visceral smooth muscle because it is found in the walls of most -viscera of the body, including the gut, bile ducts, ureters, uterus, and many blood vessels.

compare and contrast the muscle spindle and the golgi tendon organ

-the major difference in excitation of the Golgi tendon organ versus the muscle spindle is that the spindle detects muscle length and changes in muscle length, whereas the tendon organ detects muscle tension as reflected by the tension in itself. -The tendon organ, like the primary receptor of the muscle spindle, has both a dynamic response and a static response,

Describe the length of time smooth muscles are in a plateau phase of their action potentials.

-the repolarization is delayed for several hundred to as much as 1000 milliseconds (1 second) -The importance of the plateau is that it can account for the prolonged contraction that occurs in some types of smooth muscle, such as the ureter, the uterus under some con- ditions, and certain types of vascular smooth muscle. (Also, this is the type of action potential seen in cardiac muscle fibers that have a prolonged period of contraction)

Describe the role of the sodium-potassium pump in the development and maintenance of resting membrane potentials.

-there is continuous pumping of three sodium ions to the outside for each two potassium ions pumped to the inside of the membrane. The fact that more sodium ions are being pumped to the outside than potassium to the inside causes continual loss of positive charges from inside the membrane; this creates an additional degree of negativity (about -4 millivolts additional) on the inside beyond that which can be accounted for by diffusion alone. -the diffusion potentials alone caused by potassium and sodium diffusion would give a mem- brane potential of about -86 millivolts, almost all of this being determined by potassium diffusion. Then, an additional -4 millivolts is contributed to the mem- brane potential by the continuously acting electro- genic Na+-K+ pump, giving a net membrane potential of -90 millivolts.

13. Name the two major lymph ducts, state what regions they drain and state where they terminate.

-thoracic duct - empties into left subclavian vein and internal jugular (drains lymph from left part of body) -right lymph duct - empties into subclavian vein and right internal jugular

Describe the mechanism which accounts for the plateau phase of certain action potentials.

-two types of channels in heart enter into depolarization process: (1) the usual voltage-activated sodium channels, called fast channels (2) voltage-activated calcium-sodium channels, which are slow to open and therefore are called slow channels. -Opening of fast channels causes the spike portion of the action potential, whereas the slow, prolonged opening of the slow calcium-sodium channels mainly allows calcium ions to enter the fiber, which is largely responsible for the plateau portion of the action potential as well. -A second factor that may be partly responsible for the plateau is that the voltage-gated potassium channels are slower than usual to open, often not opening very much until the end of the plateau. This delays the return of the membrane potential toward its normal negative value of -80 to -90 millivolts.

What is the approximate rate of conduction of nerve impulses in a myelinated vs an unmyelinated nerve?

-unmyelinated nerves: 1 m/sec -myelinated nerves: 10-100 m/sec

occurs toward the end of ventricular contraction; it results from slow flow of blood into the atria from the veins while the A-V valves are closed during ventricular contraction. Then, when ventricular contraction is over, the A-V valves open, allowing this stored atrial blood to flow rapidly into the ventricles and causing the v wave to disappear.

-v wave

The rate of blood flow into heart from vein is called _ _ and it determines _ _ _...

-venous return -the amount of blood pumped by the heart.

Membrane potential (MP) and AP in smooth muscle

-visceral smooth muscles can develop APs with plates or spike potentials -smooth muscle cells have more voltage-gated calcium channels than sodium channels -slow wave potentials can serve as pacemaker waves in the gut -visceral (single-unit) smooth muscle produces AP's when stretched

** EXAM Q** Remember that the lens itself has a very small refractive power (15 diopters). The remaining refractive power is due to the CORNEA!!

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-The Macula is the area of the retina that surrounds the fovea centralis - with age, our eyes adapt to the dark more slowly

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1. Define the following concentrations: volume percent; weight percent; molarity; osmolarity; normality; parts per million. Be able to calculate the concentration of a substance that results when a specified weight of the substance is added to a specified volume of water.

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1. Name the major anatomic sections of the kidney and state which nephron segments are associated with each.

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1. State the average fluoride concentrations in plasma and urine for adults living in a community where the drinking water concentration is 1 ppm.

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1. State the physiologic range for urinary osmolarity in the human.

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1. What are the effects of opening up all capillaries during muscle exercise? Is the blood flow continuous?

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1. Write the functional classification for the following types of blood vessels; arteries, arterioles, capillaries, venules, and veins.

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10. Contrast cardiogenic vs hypovolemic shock.

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10. Describe and be able to identify A-V blocks from an ECG recording. List 4 causes of AV blocks.

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10. Describe the basic feedback system which regulates blood volume (see pg. 331).

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10. Describe the role of autonomic impulses to venous smooth muscle in regulating blood pressure.

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10. State the average value for normal adults of: renal blood flow; renal plasma flow; glomerular filtration rate.

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10. What is the paradox of normal kidney function in essential hypertension?

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11. Define renal fraction.

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11. Describe and be able to identify premature ventricular contraction (PVC), atrial fibrillation and ventricular fibrillation.

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11. Describe the "osmo-receptor-antidiuretic hormone system" for the control of ECF osmolarity.

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11. Given specific values for these factors, calculate the net force and determine whether net fluid movement would be directed into or out of capillaries.

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12. Define filtration fraction.

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12. Describe the aldosterone-potassium feedback system and its physiologic significance.

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12. State what would happen to the rate of net fluid filtration from capillaries into the interstitial fluid as a result of each of the following changes: a. infection (release of arteriolar vasodilators locally); b. liver disease (inadequate production of plasma protein); c. excessive loss of plasma protein via the kidneys; d. constriction of venules; e. increase of capillary permeability to plasma proteins; f. sudden hypotension due to dilation of arterioles; g. increase in interstitial fluid pressure.

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12. What are the acute effects of moderate cardiac failure? What compensatory mechanisms tend to correct

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13. Describe the role of humoral (hormonal) agents that participate in the regulation of blood flow.

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13. Describe the structure of a typical capillary bed.

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13. Name the three major mechanisms by which substances enter or leave the renal tubules.

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13. State the effects of ECF sodium and potassium concentrations on aldosterone secretion.

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13. State the significance of hyaluronic acid and other mucopolysaccharides in the interstitial fluid.

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13. What are some of the causes of hypovolemic shock due to plasma loss?

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13. What is Starling's Law of the heart for the Frank-Starling relationship?

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13. What is ventricular fibrillation? How does this affect cardiac performance? How can fibrillation be stopped?

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14. List 3 humoral agents which cause vasoconstriction; 3 which cause vasodilatation.

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14. State the effect of increased aldosterone secretion on renal sodium reabsorption and potassium excretion.

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14. What is cardiac arrest, and how does it develop?

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14. What is vasomotion? What regulates it?

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15. Compare the composition of lymph with that of plasma and that of interstitial fluid.

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15. Compare the normal concentrations of plasma and urine with respect to: osmolarity; sodium; potassium; chloride; bicarbonate; pH; fluoride.

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15. Describe the effects of sympathetic and parasympathetic nerve stimulation on cardiac function.

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15. How does one measure the mean electrical axis of the ventricle? What does the data tell You? Is it always constant, how can it change?

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15. State the effects of angiotensin on aldosterone secretion.

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15. Which of the 8 chemical factors discussed cause vasoconstriction? Which of the vasodilators also produces an indirect vasoconstrictor effect?

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16. Describe the role of vasopressin in the rapid control of arterial pressure.

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16. List the values for systolic and diastolic pressures in the pulmonary vs systemic circulation?

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16. State which part of the proximal tubular cell (apical, basal, lateral) actively transports sodium. Where is the greatest density of mitochondria within these cells?

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17. Define water diuresis and osmotic diuresis.

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17. What is a current of injury (S-T shift)?

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18. Describe the condition under which a solution can be isosmotic but not isotonic.

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18. How does gravity effect the perfusion of the top (apex) vs the bottom (base) of the lungs?

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18. State the etiology of diabetes insipidus and list its major signs and symptoms. Differentiate from diabetes mellitus.

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18. State what is meant by the term "brush border." State where this structure is found.

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19. Define thirst and salt apetite. Describe their roles in the regulation of body fluid volume and osmolarity.

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19. State the mechanism underlying the renal tubular reabsorption of water. State what percent of glomerular filtrate water is normally excreted as urine.

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2. Define osmolar concentration and calculate this value when given the molarity or normality of all the solutes in a solution.

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2. Define the term "negative feedback system" and graphically illustrate such a system in its simplest form.

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2. Describe the anatomy of the renal vascular system and its association with the major nephron segments.

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2. Describe the architecture of the loop Henle and the vasa recta. Relate this structural arrangement to the ability of the kidney to form a concentrated urine.

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2. Describe the effect that high fluoride concentrations have on the kidney that cause an increase in urine output.

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20. Define "renal erythropoietic factor" and state its major effect.

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20. State the mechanism for the tubular reabsorption of filtered proteins.

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20. What pathologic conditions restrict pulmonary blood flow?

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21. State the nephron segment into which potassium ions are secreted.

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22. Define the term tubular transport maximum (Tm). Name two substances which are reabsorbed and have Tm. Name two substances which are secreted and have a Tm.

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23. Write the formula for the: filtered load; excretion rate; reabsorption rate; secretion rate of any substance.

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26. State whether it is possible for a substance to enter the human nephron only by: glomerular filtration; tubular secretion; a combination of these two processes.

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27. State the hormone mainly responsible for regulating the distal tubular handling of sodium and potassium. State which gland secretes this hormone. State to which chemical class of substances this hormone belongs.

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3. Describe how these diseases relate to dental treatments.

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3. Differentiate the following disorders: primary diabetes insipidus; nephrongenic diabetes insipidus; diabetes insipidus fluorique.

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3. How can blood flow to muscles increase more than cardiac output during exercise? What is the role of the sympathetic nervous system in this?

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3. List the major body fluid compartments and state the percent of body weight contained in each.

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3. Name two functional features of the ascending limb of the loop of Henle which distinguish it from the descending limb. State how these features are related to the ability of the kidney to form a concentrated urine. State why the ascending limb is called the "diluting segment" of the nephron.

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3. State what is meant by the "high pressure" and "low pressure" renal vascular beds.

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3. Where in the circulatory system is the largest decrease in blood pressure, in large arteries, small arteries, arterioles, capillaries, small veins or large veins?

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4. Define autoregulation of renal blood flow and GFR. Draw the graphs which describe the relationship between pressure and renal blood flow and GFR over the pressure range of 0 to 200 mm Hg.

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4. Describe the overall renal handling of fluoride in terms of filtration, secretion and reabsorption.

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4. Describe the time periods in the cardiac cycle, when left ventricular pressure is highest and lowest. Why is the coronary blood flow higher in the left than in the right ventricle?

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4. Describe what would happen to urinary flow rate and urinary osmolarity if an agent (e.g. fluoride) were to interfere with the normal operation of the renal countercurrent multiplier system such that the hypertonicity of the interstitial fluid in the medulla was reduced.

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4. Diagram the normal renal-body fluid regulating system and discuss the functional significance of each of its components (see Handout #1).

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4. Give examples of interaction between the two situations.

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4. What is the relationship between arterial oxygen saturation and blood flow?

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5. Define pressure diuresis and pressure natriuresis.

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5. Describe the anatomy and function of the: juxtaglomerular cells; macula densa; juxtaglomerular apparatus.

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5. For a slightly thirsting human, state the expected osmolarity of the fluid in the: glomerular filtrate; late proximal tubule; middle segment of the descending limb of the loop of Henle; bend in the loop; middle segment of the ascending limb of loop; early distal tubule; late distal tubule; middle collecting duct; final urine.

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5. State the usually reported average value for the renal plasma clearance of fluoride in healthy adult humans.

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5. What is the alarm reaction?

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6. Describe how each of the following affect temperature regulation, and how each would be treated clinically: heat cramps.

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6. Describe how each of the following affect temperature regulation, and how each would be treated clinically: heat exhaustion

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6. Describe how each of the following affect temperature regulation, and how each would be treated clinically: heat stroke

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6. Describe the anatomy of the glomerulus, the process of glomerular filtration, and the composition of the glomerular filtrate.

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6. Describe the relationship between arterial blood pressure and urine output and how this helps to prevent hypotension and hypertension.

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6. State the pKa of HF (hydrogen fluoride or hydrofluoric acid). At the minimum pH of human urine (assume 4.45), what percent of urinary fluoride would exist as HF?

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7. Define the term "glomerular marker." Name two such markers.

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7. Describe the mechanism of fluoride reabsorption (nonionic diffusion) from the nephron.

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7. Name two factors that can influence medullary interstitial hypertonicity.

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7. What is the mechanism for the development of "Vasoconstrictor Hypertension"?

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8. Define and write the formula for the renal plasma clearance of any substance.

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8. Distinguish between acute coronary occlusion and myocardial infarction.

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8. Name the two factors that must be present if a concentrated urine is to be formed.

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9. Describe and demonstrate by calculation, the Fick and Indicator dilution methods for measuring cardiac output.

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9. Describe the function of the "low pressure receptors".

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9. State what happens to proteins which escape from the capillaries and enter the interstitial fluid.

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9. With regard to antidiuretic hormone (ADH), state: the site of its synthesis; the structure from which it is released; the major physiologic variable which regulates its rate of secretion; its target site; its major physiologic effect.

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A solution of 1/1000 osmole per kg has an osmolality of 1 milliosmole per kg.

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Arcuate nucleus neuron pools that produce orexigenic substances, neuropeptide Y (NPY) and agouti-related protein (AGRP) activate paraventricular nuclei to increase food intake, increase energy expenditure and increase SNS activity via the nucleus tractus solitarius in the brainstem.

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Compare the activity and function of multi-unit vs visceral smooth muscle.

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Contraction and Excitation of Smooth Muscle (Chap 8)

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Describe the chemical and electrical events associated with the generation of an end-plate potential.

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Describe the differences in ionic composition of intracellular and extracellular fluids.

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Describe the method used for direct measurements of membrane potentials in nerve and muscle.

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Endothelin: This a powerful vasoconstrictor released primarily from damaged endothelium. It is a large 21 amino acid peptide. The usual stimulus for release is damage to the endothelium. After severe blood vessel damage, release of local endothelin and subsequent vasoconstriction helps to prevent extensive bleeding. Enhanced endothelin release may also contribute to vasoconstriction when the endothelium is damaged by hypertension or other similar conditions. Drugs blocking endothelin receptors have been used to treat pulmonary hypertension.

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F retention will increase if flow rate increases only if urinary pH also increases

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Give a diagram of an action potential waveform, label each phase and describe the ion movements occurring during each phase.

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IO: Describe the structure and function of the neuromuscular junction. List the types of drugs that can effect neuromuscular junction transmission. Stimulators and inhibitors.

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Normal osmolality of EC and IC fliuds ~300 milliosmole per kg, and the osmotic pressure of these fluids ~5500 mm Hg.

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Outline the transport system for extracellular fluid.

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Right bundle branch block showing greatly prolonged QRS complex

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The student will contrast isometric vs isotonic muscle contraction in terms of forces, blood flow, etc..

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The student will contrast the fatigibility, blood supply, color, speed, glycogen content and motor unit size and fast-glycolytic, fast-oxidative and slow-oxidative muscle fibers.

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The student will know the definition of motor units and how they function in twitch vs tetanizing conditions, how muscle contraction can be graded by spatial vs temporal summation.

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The student will understand sarcomeric structures, the sliding filament hypothesis and how muscle contraction is activated and how muscles relax.

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What are the effects of local anesthetics on skeletal muscles vs nerves?

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What are the two different neurotransmittor substances released by autonomic nervous system neurons that innervate smooth muscle? Do they always have the same action on all tissues?

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What causes muscle pain during fatigue? How can that pain be simulated? Where is that pain referred?

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What would happen to a resting membrane potential if the extracellular potassium concentration fell from 5 down to 2.5 mEq/L? What would be the functional consequences? What would happen to the resting membrane potential if the extracellular potassium concentration rose from 5 to 140 mEq/L? What would be the functional consequences?

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Enlargement in total mass of muscle is called

muscle hypertrophy -Muscle hypertrophy results from an increase in # of actin and myosin filaments (due to split), and this usually occurs in response to contraction at maximal or near maximal force. -It is known, however, that the rate of synthesis of muscle contractile proteins is far greater when hypertrophy is developing, leading also to progressively greater numbers of both actin and myosin filaments in the myofibrils, often increasing as much as 50 per cent. In turn, some of the myofibrils themselves have been observed to split within hypertrophying muscle to form new myofibrils, but how important this is in usual muscle hypertrophy is still unknown. -Along with the increasing size of myofibrils, the enzyme systems that provide energy also increase. This is especially true of the enzymes for glycolysis, allowing rapid supply of energy during short-term forceful muscle contraction.

2 types of special sensory receptors

muscle spindles (MS) and Golgi tendon organs (GTO).

Even when muscles are at rest, a certain amount of tautness usually remains. This is called

muscle tone

4. What two factors cause a hypereffective heart?

nervous stimulation and hypertrophy of the heart muscle. Nervous stimulation: Increased sympathetic and decreased parasympathetic (both rate and force of contraction of heart increase). Hypertrophy of heart: Increased workload on heart (up to a certain limit that does not cause damage) can increase its mass (hypertrophy) and force of contraction. Heavy exercise also increases skeletal muscle mass/hypertrophy and activity similarly. Relatively, hypertrophy-induced hyper-effectiveness is a long-term effect.

List two major systems for regulating body functions.

nervous system - coordination between sensory and motor activities (receptor/effector) endocrine system

Name the major neurotransmitters at each of the following: c. sympathetic neuroeffector junction;

norepinephrine (NE) or Ach, depending on the fiber. The neuroeffector jxn means the junction of the postganglionic fiber and the effected organ that it is sending signals to.

Which hormones influence the excitability of smooth muscle cells?

norepinephrine, epinephrine, acetylcholine, angiotensin, endothelin, vasopressin, oxytocin, sero- tonin, and histamine (A hormone causes contraction of a smooth muscle when the muscle cell membrane contains hormone- gated excitatory receptors for the respective hormone. Conversely, the hormone causes inhibition if the mem- brane contains inhibitory receptors for the hormone rather than excitatory receptors.)

11. Account for the normal negativity of interstitial fluid pressure.

normal negativity in interstitial fluid pressure lymph pump -> causes -3mmHg, which holds the tissues together - slight suction in tissues -indirect pumping of proteins into lymph vessels -indirect pumping of fluid into lymph vessels ...

at what percentage of total blood loss does does CO and AP begin to decrease; are they the same>

not the same -CO begins to decrease after 10% blood loss -AP begins to decrease after 20% -both reach zero with 35-45% removal of blood

8. Define conductance and relate it to vascular diameter using Poiseuille's law. How is this related to sympathetic activity and critical closing pressure?

onductance. This is a measure of the blood flow through a vessel for a given pressure difference. It is usually expressed in ml per sec per mm Hg pressure. Conductance is the reciprocal of resistance and can be expressed as: Conductance = 1/Resistance So, the conductance of the vessel increases proportionally to the fourth power of the diameter

• Rods and cones synapse with bipolar cells (12 types) which synapse with ganglion cells. • Axons of the ganglion cells converge and leave the eye as the _ _.

optic nerve.

Under certain conditions concentration difference for water can develop across a membrane; that is, net movement of water occurs, causing cells to either swell or shrink. The magnitude of pressure difference required to stop osmosis is

osmotic pressure

8. Define oncotic pressure.

osmotic pressure due to substance that doesn't diffuse readily (like proteins)

combining oxygen with the end products of glycolysis and with various other cellular foodstuffs to liberate ATP

oxidative metabolism More than 95 per cent of all energy used by the muscles for sustained, long- term contraction is derived from this source.

chemical linkage between amino acids that form proteins.

peptide bonds

Ejection

period of ejection into aorta -beginning of blood pressure -pressure will be more than 80 mm Hg or valve will not open

3. What is the relationship between venous return (or cardiac output) and total peripheral resistance?

peripheral factors that affect blood flow into the heart from the veins affect the amount of venous return ; in fact, peripheral factors are more important the the heart itself in controlling CO

• Rods and cones are located next to the _(dark) _ at the back of the globe.

pigment epithelium

14. State the difference between "pitting edema" and "dependent edema."

pitting edema - when positive pressure -can press on the skin and leave a depression -not dependent on gravity dependent edema - dependent on gravity like when ankles swell...

central compartment is

plasma

% of total body weight

plasma = 5% TBW = 60% ECF = 20% ICF = 40% ISF = 15%

What event triggers the activation of the gates?

positive feedback initiated by the nerve signal

Sensory signal enters the spinal cord via the sensory roots; what is an anatomically descriptive name for these roots?

posterior roots

what ion contributes to repolarization in cardiac muscle (as well as cardiac muscle)

potassium

Why does the membrane of the heart control center not depolarize immediately after it has become re- polarized, rather than delaying for nearly a second before the onset of the next action potential?

potassium conductance

The diffusion of what ion determines the magnitude of the resting membrane potential?

potassium ions

what is the tilting of the myosin head as a result of head attachment to an active site on actin?

power stroke

6. State the physical event responsible for vasomotion and the major factor which determines its rate (see pg. 163).

pre-capillary sphincter at junction of preferential and true arterioles relax to let vasomotion occur -local oxygen pressure determines whether sphincter will open -tissue compliance but no muscle -fat soluble substances

Molecules are "pumped" against a concentration gradient (or uphill) at the expense of energy from ATP or similar sources. - direct use of energy involved.

primary active transport

active transport is divided into two categories

primary active transport secondary active transport

8. In what plane do the "precordial leads" (V1 - V6) orient the electrical axis of the heart?

recorded from anterior chest wal

in spatial summation, the increase in force of contraction that develops as progressively more motor units are activated is called.

recruitment

location, function, and significance of papillary muscles

regulatory factor that keeps valve functioning tightly - keeps valve from bulging back

diastole

relaxation of ventricle

required daily amount of vitamins

required daily amount of vitamins

List the systems and organs that provide nutrients to the extracellular fluid.

respiratory - lung cardiovascular - heart digestive - stomach

List-three stages relating to ionic permeability which occur during the course of an action potential in their proper sequence.

resting (-90mv) depolarization - (Na+ activated b/w -90 to +35 mV) repolarization -(Na+ inactivated b/w +35 to -90mV, delayed)* (slow activation of K+ channels (+35 to -90mV) (hyperpolarization) *The Na+ inactivation gate, however, closes a few 10,000ths of a second after the activation gate opens. That is, the conformational change that flips the inactivation gate to the closed state is a slower process than the conformational change that opens the activation gate.

Describe the changes in the voltage-gated sodium and potassium channels which account for the altered permeability during the action potential? What event triggers the activation of the gates?

resting - voltage gated sodium channel: activation gate closed/inactivation gate open depolarization - sodium activation gates open (activate) and sodium ions pour in (channels open usually b/t -70 and -50mv); the fiber becomes depolarized repolarization - sodium inactivation gate begins to close (no more sodium coming in) and submembranal gate on potassium channels open more allowing rapid potassium diffusion to the exterior of the cell reestablishing resting potential. (K+ voltage gates experience slow activation from +35 to -90mV)

Define resting membrane potential. What is its magnitude in a typical nerve fiber?

resting membrane potential is negative (-90millivolts)

Ordinarily, each impulse that arrives at the neuromuscular junction causes about three times as much end plate potential as that required to stimulate the muscle fiber. Therefore, the normal neuromuscular junction is said to have a high

safety factor

cell membrane of skeletal muscle cell is called

sarcolemma -The sar- colemma consists of a true cell membrane, called the plasma membrane, and an outer coat made up of a thin layer of polysaccharide material that contains numerous thin collagen fibrils.

The portion of the myofibril (or of the whole muscle fiber) that lies between two successive Z discs is called a

sarcomere - the functional contractile unit of skeletal

myofibrils are suspended inside the muscle fiber in a matrix of...

sarcoplasm The spaces between the myofibrils are filled with intracellular fluid containing large quantities of potassium, magnesium, and phosphate, plus multiple protein enzymes. This intracellular fluid is called

shortly after acetylcholine is synthesized in the axonal terminal, it is absorbed into many small...

shortly after acetylcholine is synthesized in the axonal terminal, it is absorbed into many small...synaptic vesicles, about 300,000 of which are normally in the terminals of a single end plate.

(1) Smaller fibers. (2) Also innervated by smaller nerve fibers. (3) More extensive blood vessel system and capillaries to supply extra amounts of oxygen. (4) Greatly increased numbers of mitochondria, also to support high levels of oxidative metabolism. (5) Fibers contain large amounts of myoglobin, an iron- containing protein similar to hemoglobin in red blood cells. Myoglobin combines with oxygen and stores it until needed; this also greatly speeds oxygen transport to the mitochondria. The myoglobin gives the slow muscle a reddish appearance and the name red muscle, whereas a deficit of red myoglobin in fast muscle gives it the name white muscle.

slow fibers (type I, red muscle) are smallest, innervated by smaller # of fibers and have large # of mitochondria.

cause of size principle in multiple fiber summation

smaller motor units are driven by small motor nerve fibers, and the small motoneurons in the spinal cord are more excitable than the larger ones, so they naturally are excited first.

multi-fiber summation aka force summation aka?

spatial summation

summation from multiple neurons; multiple fiber summation is aka

spatial summation above: the relationship between the force of contraction and number of active motor units.

Einthoven's Triangle and Einthoven's Law

sum of voltage from leads I and III= voltage of Lead II I + III = II 0.5mV + 0.7mV = 1.2mV

absorptive anatomy of the intestinal mucosa including the valvulae conniventes, villi, microvilli

surface area contributors: (most to least) -MICROVILLI- increase surface area another 20 fold, 1um in length, ~0.1um in diameter -VILLI- increase surface area another 10 fold, protrude ~1 mm from surface. -VALVULAE CONNIVENTES - increase surface area 3 fold, protrude ~8mm into lumen of the gut

compare the stimuli from sympathetic and parasympathetic nervous systems

sympathetic - fight or flight parasympathetic - calming, restorative stimulus

an electron micrographic sketch of the junction between a single axon terminal and the muscle fiber membrane.

synaptic gutter or synaptic trough - invaginated membrane -numerous small folds of muscle membrane at bottom of gutter called subneural clefts; these greatly increase the surface area at which the synaptic transmitter can act. -synaptic space or synaptic cleft: space between the terminal and the fiber membrane (This space is 20 to 30 nanometers wide.)

t/ f~60% adult human body is fluid- mainly water solutions of ions and other substances/nutrients needed to maintain cell life.

t

t/f "Dynamic" Response as Rate of Change of Receptor Length is a function of Response of the Primary Ending but Not the Secondary Ending; while "static" response is a function of both primary and secondary nerve endings

t

t/f A special feature of the Na+-K+ ATPase pump is that its degree of activity is strongly stimulated when excess sodium ions accumulate inside the cell membrane. In fact, the pumping activity increases approximately in proportion to the third power of this intracellular sodium concentration.

t

t/f Circuits in spinal cord process sensory information and are able to generate motor activity.

t

t/f Diffusion is caused by kinetic motion molecules in both the plasma and interstitial fluid.

t

t/f Many obese humans have higher than normal blood levels of leptin. This suggests that they may have leptin resistance in a manner similar to insulin resistance in type II diabetes mellitus.

t

t/f Maximum contraction occurs when there is maximium overlap between the actin and cross bridge of the myosin filaments, supporting the idea that the greater the # of cross-bridges pulling the actin filaments, the greater the strength of contraction.

t

t/f Most muscle activity involves activation of only a fraction of the total number of motor units in a muscle.

t

t/f Normally, particularly when there is some degree of gamma nerve excitation, the muscle spindles emit sensory nerve impulses continuously.

t

t/f Please note that if no difference in pressure exists between the two ends, there will be no flow despite the presence of pressure.

t

t/f Sensory signal enters the spinal cord via the sensory (posterior) roots and synapse on cord gray matter at the anterior motor horn motor neurons and interneurons

t

t/f The kidney- excretes most of the waste products (besides CO2)

t

t/f The viscosity of blood plasma is ~ one-and-a half times that of water.

t

t/f Thus, the atria act as primer pumps for the ventricles, and the ventricles in turn provide the major source of power for moving blood through the body's vascular system.

t

t/f Villi are found to a much smaller extent in the large intestine and not at all in the stomach. Therefore, the stomach and colon are not designed for efficient absorption.

t

t/f ions can flow with ease through the axonal membrane via the nodes of ranvier, hence AP.

t

t/f muscle spindle reflex tends to maintain a constant length of muscle

t

t/f the degree of damping of arterial pulsation is nearly directly proportional to the product of resistance and compliance.

t

t/f the entire muscle fiber has light and dark bands, as do the individual myofibrils. These bands give skeletal and cardiac muscle their striated appearance.

t

t/f velocity of conduction generally increases with fiber diameter

t

t/f Interneurons are present in all areas of the cord gray matter—in the dorsal horns, the anterior horns, and the intermediate areas between them

t -interneurons are 30 times as numerous as the anterior motor neurons. -small and highly excitable, -often exhibiting spontaneous activity and capable of firing as rapidly as 1500 times per second. -many interconnections with one another -many synapse directly with alpha motor neurons -The interconnections among the interneurons and anterior motor neurons are responsible for most of the integrative functions of the spinal cord.

t/f 98% of muscle fibers have only one neuromuscular junction

t Each nerve ending makes a junction with the muscle fiber near its midpoint. The action potential initiated in the muscle fiber by the nerve signal travels in both directions toward the muscle fiber ends.

t/f actin and myosin filaments derived from smooth muscle interact with each other in much the same way that they do in skeletal muscle. Further, the contractile process is activated by calcium ions, and adenosine triphosphate (ATP) is degraded to adenosine diphosphate (ADP) to provide the energy for contraction.

t However, there are major differences between the physical organization of smooth muscle and that of skeletal muscle, as well as differences in excitation- contraction coupling, control of the contractile process by calcium ions, duration of contraction, and amount of energy required for contraction.

t/f Most muscles in the body contract in both modes - isotonic and isometric (mixed) What are some examples of muscles contracting solely in one of each mode and an action that would involve both modes?

t Isometric contraction of quadriceps during standing; isotonic contraction of biceps when weight is lifted; contraction of leg muscles during running involving both types.

t/f the dense bodies of smooth muscle serve the same role as the Z discs in skeletal muscle.

t The contractile unit of smooth muscle is similar to the contractile unit of skeletal muscle, but without the regularity of the skeletal muscle structure

t/f All the muscles of the body are continually being remodeled to match the functions that are required of them.

t Their diameters are altered, their lengths are altered, their strengths are altered, their vascular supplies are altered, and even the types of muscle fibers are altered at least slightly. This remodeling process is often quite rapid, within a few weeks.

t/f The smooth muscle cell membrane has far more voltage-gated calcium channels than does skeletal muscle but few voltage- gated sodium channels.

t Therefore, sodium participates little in the generation of the action potential in most smooth muscle. Instead, flow of calcium ions to the interior of the fiber is mainly responsible for the action potential. This occurs in the same self-regenerative way as occurs for the sodium channels in nerve fibers and in skeletal muscle fibers. However, the calcium channels open many times more slowly than do sodium channels, and they also remain open much longer. This accounts in large measure for the pro- longed plateau action potentials of some smooth muscle fibers.

t/f When a muscle contracts against a load, it performs work. This means that energy is transferred from the muscle to the external load to lift an object to a greater height or to overcome resistance to movement.

t W = L x D in which W is the work output, L is the load, and D is the distance of movement against the load. The energy required to perform the work is derived from the chemical reactions in the muscle cells during contraction

t/f Under rare conditions of extreme muscle force generation, the actual number of muscle fibers has been observed to increase (but only by a few percentage points), in addition to the fiber hypertrophy process. This increase in fiber number is called fiber hyperplasia. When it does occur, the mech- anism is linear splitting of previously enlarged fibers.

t Yet another type of hypertrophy occurs when muscles are stretched to greater than normal length. This causes new sarcomeres to be added at the ends of the muscle fibers, where they attach to the tendons. In fact, new sarcomeres can be added as rapidly as several per minute in newly developing muscle, illustrating the rapidity of this type of hypertrophy.

t/f every muscle of the body is composed of a mixture of so-called fast and slow muscle fibers, with still other fibers gradated between these two extremes.

t this includes the third type of muscle fiber referred to as intermediate fibers

t/f All fibers are the same type (fast or slow) in a given motor unit.

t • Small motor units: As few as 10 fibers/unit; more precise control (eg., larnyx). • Large motor units: As many as 1000 fibers/unit; coarse control (eg, quadriceps). •Motor units can overlap, which provides coordination . • Thus. depending on fiber size and energetics of contraction, different speeds of muscle contraction occur (see fig.). Muscles that react rapidly are mainly composed of fast fibers, which are large, contain more extensive SR, have rapid energy source.

t/f 80 per cent of the blood flows directly through the atria into the ventricles even before the atria contract. Then, atrial contraction usually causes an additional 20 per cent filling of the ventricles.

t - -atria serves as primer pumps that increase the ventricular pumping effectiveness as much as 20 percent.

t/f Pressure gradient in the pulmonary circulation is lower than that of the systemic circulation, although blood flow is the same in both.

t - Thus, the total pulmonary vascular resistance is significantly lower.

frequency summation is aka

temporal summation

type of frequency summation (occurs from a single neuron)

temporal summation

As the cardiac RP lasts throughout the contraction (ie., takes same period), it prevents the myocardium from getting tetanized by repeated stimulation.

tentanization not observed in cardiac muscle because of overlap

in frequency summation/temporal summation, at higher frequencies of stimulation the successive contractions fuse together and this state is called

tetanization.

The period during which a second action potential cannot be elicited, even with a strong stimulus, is called

the absolute refractory period

10. How can one estimate venous pressure?

the pressure in the right atrium is called the central venous pressure. Simple observation of the degree of distention of the peripheral veins (especially of the neck veins) can be used to estimate venous pressure. Venous pressure can also be measured more directly by inserting a needle into a vein and connecting it to a pressure recorder. Also, right atrial pressure can be measured accurately is by inserting a catheter through the peripheral veins and into the right atrium. Measurements via such central venous catheters are to assess pumping ability of the heart;

1. What membrane events produce the slow depolarization that occurs in the sinus node during diastolic filling of the ventricles?

the resting potential of the sinus node is much lower (in comparison with -85 to -90 millivolts for the ventricular muscle fiber) therefore the fast Ca channels have already become "inactivated"; the cause of this lesser negativity is that the cell membranes of the sinus fibers are naturally leaky to sodium and calcium ions, and positive charges of the entering sodium and calcium ions neutralize much of the intracellular negativity. only the slow sodium-calcium channels can open (i.e., can become "activated") and thereby cause the action potential. As a result, the atrial nodal action potential is slower to develop than the action potential of the ventricular muscle. Also, after the action potential does occur, return of the potential to its negative state occurs slowly as well, rather than the abrupt return that occurs for the ventricular fiber.

When an action potential spreads over the terminal, the calcium channels open and allow calcium ions to diffuse from where to where?

the synaptic space to the interior of the nerve terminal.

functional absorptive unit of small intestine?

the villus

why do multi-unit smooth muscles contract in response to nerve stimuli without APs?

they are too small and do not have enough sodium channels

4. Name the major neurotransmitters at each of the following:a. neuromuscular junctions;

this is referring to skeletal (voluntary) muscles. These junctions use Acetycholine (Ach) to transmit signals

5. State the location of most of the sympathetic nervous system (SNS) ganglia.

thoracolumbar region are located very close to the spinal cord, in two chains of ganglia that run up along the spinal cord. (paravertebral sympathetic chain of ganglia -This means that the preganglionic fiber is very SHORT (goes from the cord to the ganglion) and the postganglionic fiber is very LONG (travels all the way to the effected organ)

threshold for initiation of the action potential

threshold for stimulation = -65 mV An action potential will not occur until the initial rise in membrane potential is great enough to potentiate the influx of Na+ ions into the cell. This occurs when the number of Na+ ions entering the fiber becomes greater than the number of K+ ions leaving the fiber. A sudden rise in membrane potential of 15 to 30 millivolts usually is required. Therefore, a sudden increase in the membrane potential in a large nerve. fiber from -90 millivolts up to about -65 millivolts usually causes the explosive development of an action potential. This level of -65 millivolts is said to be the threshold for stimulation.

to cause maximum muscle contraction, current must penetrate deeply into the muscle fiber to the vicinity of the separate myofibrils. This is achieved by transmission of action potentials along _ _ that penetrate all the way through the muscle fiber from one side of the fiber to the other.

transverse (T) tubules

**10. Describe the tubular reabsorption of bicarbonate.

tubular reabsorption of bicarbonate: - bicarbonate reabsorption is essentially the REVERSE of ( H2O + CO2 ↔H2CO3 ↔ H+ + HCO3-) - Bicarbonate ions (HCO3- ) cannot get through the tubule epithelium cells (because it is charged) So if the body didnt have a mechanism to get around this, we would excrete tons of bicarbonate in the urine (which would totally mess up the buffering system) - As H+ is secreted INTO the tubule fluid, HCO3- picks it up, and becomes H2CO3. H2CO3 dissociates into H2O + CO2 . In this form, CO2 can easily diffuse back into the tubule epithelial cell. -Once CO2 enters the cell, it joins H2O to form H2CO3 again (remember that you need carbonic anhydrase to do this. - H2CO3 dissociates into H+ and HCO3- - The bicarbonate ion is released back into the blood. -This is a complicated system, but the result is bicarbonate ions being reabsorbed from the tubule fluid back into the blood. BUT- the ion that enters the blood stream is not the same molecule that was in the tubule fluid.

Mammalian skeletal muscle has how many T tubules per sarcomere and location?

two tubules/sarcomere located at the A-I band junctions

1. List the major routes by which water is lost from the body. State the amounts of water lost daily by these routes under normal temperature and activity conditions.

urine sweat feces expiration

what nerve is mainly responsible for the parasympathetic innervation in the heart

vagus

1. Distinguish between vascular distensibility and vascular compliance.

vascular distensibility - Vascular distensibility = Increase in volume/Increase in pressure X original volume vascular compliance - It measures the ability blood vessels to store blood.

the sum of all total blood flow from individual segments of the peripheral circulation

vascular resistance

unction as conduits for transport of blood from the venules back to the heart; serve as a major reservoir of extra blood; have very low pressure and thin wall, but are muscular enough to contract or expand and thereby acting as a controllable reservoir for the extra blood.

veins

what is the order of percent blood volume in the various components of the systemic CVS from highest to lowest (of the 84% of total blood volume in the systemic circulation;the other 16% is in the heart and lungs)

veins < arteries < sys. arterioles

what is the primary controller of CO?

venous return

Isovolumic Relaxation

ventricle starts to relax but doesn't change its volume

What happens when diastolic ventricular volume are increased?

ventricular diastolic pressure increases

Collect blood from the capillaries and gradually coalesce into progressively larger veins.

venules

2. Define "visceral reflex" and give an example of such a reflex.

visceral stimuli (eg, spicy food stimulates gastric secretions) = sensory information that travels to the autonomic gangion, or brainstem, or hypothalamus, can AUTOMATICALLY send responses back to the effected organ. (does not have to involve brain)

channel plays an important role in increasing the rapidity of repolarization

voltage-gated potassium channel

channel involved in depolarization and repolarization

voltage-gated sodium channel

how are T-tubules internal extensions of the cell membrane

where the T tubules originate from the cell membrane, they are open to the exterior of the muscle fiber. Therefore, they communicate with the extracellular fluid surrounding the muscle fiber, and they themselves contain extracellular fluid in their lumens.

phosphocreatine as energy for contraction

which carries a high-energy phosphate bond similar to the bonds of ATP. The high-energy phosphate bond of phosphocreatine has a slightly higher amount of free energy than that of each ATP bond; its released energy causes bonding of a new phosphate ion to ADP to reconstitute the ATP. However, the total amount of phosphocreatine in the muscle fiber is also very little—

small glucose polymers ​

​maltose= glucose + glucose ​ ​lactose = glucose + galactose ​ ​sucrose= fructose + glucose

Metabolic Factors that Dilate Coronary Arteries

• CO2 • O2 tension (drop in tension) • lactic acid • H+ • histamine • K+ • prostaglandins • adenosine

Rheumatic Valvular Lesions

• A major valvular lesion • Autoimmune disease in which valves are damaged. • Unusually initiated by streptococcal toxin (almost always from group A hemolytic streptococci). • Bacteria release proteins against which antibodies are formed. • The antibodies react not only with the bacterial antigens but also against many different tissues of the body, including the heart valves, often causing inflammation and damage. • The mitral and aortic valves are more affected. • Lesions can become scar tissues that may fuse together to become solid scarred masses • If blood flow is blocked, the scarred mass becomes stenosed, and if the valves are not able to close during ventricular contraction, regurgitation (back flow) of blood occurs.

9. Describe the sequence of events that occur in heart muscle following a myocardial infarction?

• After acute coronary occlusion, the area of muscle with zero or little (non-functional) flow is said to be infarcted (process: myocardial infarction). • In an infract where there is no collateral blood flow, muscle dies.

7. What do the various conditions which cause a chronic increase in cardiac output all have in common?

• All result from chronically reduced total peripheral resistance • None results from excitation of the heart itself.

Absorption of Vitamin B12

• B12 required for DNA synthesis: Essential for conversion of ribose nucleotides to deoxyribose nucleotides • Inadequate B12 inhibits nuclear maturation (early clinical sign is pernicious anemia) • INTRINSIC FACTOR (from gastric parietal cells) binds with B12 to prevent destruction by stomach acid and enzymes and aid in intestinal absorption of B12 • In cases of gastric atrophy or gastrectomy, B12 can be administered parentally (administered anywhere but the GI tract)

treatment of shock

• Blood transfusion • Plasma substitute (Dextran) • Symopathomimetic agent (epinephrine) • Fluid transfusion • Head-down position (head at least 12 inches lower than feet helps in promoting VR) • Oxygen therapy • Glucocorticoids (help cardiac function and prevent release of lysosomal enzymes into cell cytoplasm)

10. What are the four major causes of death following acute coronary occlusion?

• Decreased cardiac output (cardiac, cardiogenic or coronary shock) - muscle contraction is weak, and this leads to cardiac failure • Damming of blood in the venous system - heart not pumping blood forward, damming it in pulmonary and systemic veins, resulting in edema, etc. • Rupture of the infarcted area of heart - occurs with muscle degeneration and becoming weak - with rapture loss of blood into pericardium occurs, developing cardiac tamponade (compression of heart from outside). • Fibrillation of the ventricles - could occur suddenly after infarction (injury current)

Mechanisms of excitation-contraction coupling and relaxation in cardiac muscle.

• Diffusion of calcium into myofibrils promotes muscle contraction by similar mechanisms as in SKM. AP • The T tubules in cardiac muscle are 25x bigger, enabling greater Ca release. • Also, cardiac muscle contraction is highly dependent on EC calcium influx. • Ca is removed during relaxation by Ca pump (into SR) and by Na/Ca exchanger in CM (linked to Na-K ATPase).

Short-term, inhibitory regulation of food intake

• Gastrointestinal filling - stomach stretch sensed via vagal to suppress feeding center. • Cholecystokinin from fat in the duodenum decreases feeding via activation of melanocortin path in hypothalamus. • Peptide YY secreted by ileum and colon in response to fat decreases feeding (anorexigenic). • Chewing, tasting, swallowing, salivation inhibits feeding center (the "head receptor metering" mechanism).

three examples of systems for control used to maintain homeostasis

• Genetic control at cellular level • Control within individual organs • Control of interactions among organs throughout the entire body (eg,. regulation of O2 and CO2 concentrations in EC fluid, which involves both the respiratory and nervous systems)

6. How does sympathetic stimulation of the heart increase coronary blood flow if norepinephrine causes coronary vasoconstriction?

• Heart innervated by the ANS and stimulation of the ANS affects coronary flow in 2 ways: - Direct effect resulting from direct action of released Ach and NE on coronary vessels. - Indirect effect resulting from secondary changes in coronary blood flow caused by increased or decreased activity of the heart due to actions of EP or Ach, respectively (recall mechanism from previous slides). During increased activity by NE, for example, heart metabolism is enhanced causing local vasodilation and ↑blood flow, and vise versa. The indirect mechanism plays a more important role. • As sympathetic innervation of coronary vessels is greater than para innervation, sympathetic control of the bv plays relatively a more important role

Patent Ductus Arteriosus (PDA):

• In fetus, pulmonary artery blood goes to the aorta via ductus arteriosus, bypassing the lungs. The blood is oxygenated by the placenta of the mother. Normally, blood flow through the ductus ceases at birth, thereby causing the ductus to close. • However, in 1:5500 babies, the ductus never closes, causing PDA. • This condition allows a portion of the oxygenated blood in the aorta to flow back to the lungs through pulmonary artery. • If uncorrected, this leads to serious complications affecting the heart as well as the lungs.

T-tubules function, location, structural composition?

• Invaginations of the sarcolemma filled with EC fluid • Penetrate the muscle fiber, branch and form networks • Transmit APs deep into the muscle fiber -Excitation-Contraction Coupling: Transverse (T) tubule/SR System: -Note that the T tubules communicate with the outside of the cell membrane, and deep in the muscle fiber; each T tubule lies adjacent to the ends of longitudinal sarcoplasmic reticulum tubules that surround all sides of the actual myofibrils that contract.

effects of Hydrofluoric Acid on the Stomach: Lessons Learned

• Ionic F (up to at least 300 ppm) has no effects • HF at as little as 30-40 ppm causes damage • Do not swallow toothpaste (1000 ppm F) • Do not swallow mouthrinse (230-1000 ppm F) • Use recommended procedures for APF gel topical treatment (12,300 ppm F) • Chew of suck dietary fluoride supplement tablets and swallow with plenty of water

effects of Hydrofluoric Acid on the Stomach: Lessons Learned

• Ionic F (up to at least 300 ppm) has no effects • HF at as little as 30-40 ppm causes damage • Do not swallow toothpaste (1000 ppm F) • Do not swallow mouthrinse (230-1000 ppm F) • Use recommended procedures for APF gel topical treatment (12,300 ppm F) • Chew or suck dietary fluoride supplement tablets and swallow with plenty of water

5. What regulates coronary blood flow?

• Local mechanism is the primary controller of coronary blood flow - Local arterial vasodilation occurs in response to cardiac muscle's need for nutrition (regardless of cause) and vise versa. • Oxygen demand is a major factor in local blood flow regulation. - Heart depends significantly on the supply of O2 and ~70% of O2 in coronary blood is removed as blood passes through heart at rest. - Blood flow increases in proportion to metabolic consumption of O2 by heart. - Decrease in O2 is believed to cause release of vasodilator substances from heart muscle cells.

two types of smooth muscle

• Multi-unit: Each fiber can contract independently of the others and often is innervated by a single nerve ending; control exerted mainly by nerve signals (eg., ciliary, iris muscles). • Single-unit (unitary, visceral): Many contract together as a unit; CM joined by gap junctions for AP travel (eg., gut, bile duct, ureter, uterus, bv muscles).

Classes of amino acids for which there are specific transporters:

• Neutral • Acidic • Basic • Proline • Hydroxyproline

stages of shock

• Non-progressive stage: Normal circulatory compensatory mechanisms cause full recovery without outside help • A progressive stage: Without medical intervention, shock becomes steadily worse until death • An irreversible stage: Shock has extensively progressed and patient does not respond to all forms of known therapy. Hemorrhage or decreased blood volume demonstrates different stages of circulatory shock.

two functions of the static stretch reflex during muscle contraction and identify the most important one.

• Nullifying the effects of extra load - via load reflex. • Prevention of oscillations; providing damping or smoothing action (the signal averaging function of muscle spindle).*

7. State the spinal origins of the SNS.

• Pre-ganglionic axons synapse with long post-ganglionic axons in sympathetic chain Spinal origins of sympathetics- thoraco lumbar *** EXAM Q *** - nerves come out of the thoracic and lumbar segments of the spinal cord (T1-L2) - The cell body lies in the intermediolateral horn of the spinal cord - as the preganglionic fibers leave the spinal cord, most travel through the white ramus of the sympathetic ganglion. - exception- fibers that will innervate sweat glands, erector pilli muscles (goose bumps), and a few blood vessels travel through the grey ramus

Factors Affecting Heart Sound Intensity

• Rate of rise of ventricular pressure • Physical characteristics of the ventricles and valves • Volume of the heart • Transmission characteristics of the chest wall.

Phasic changes of coronary blood flow during systole and diastole

• Resting coronary blood flow ~ 225 mi/min. • Coronary flow increases during exercise to supply extra nutrient to heart. • Blood flow in LV falls during systole (opposite to flow in other bv of body) due to the strong compression of the LV. • No such compression during diastole. • Similar phases occur for blood flow through the RV but much less pronounced.

RHODOPSIN-RETINAL VISUAL CYCLE IN RODS (similar reaction occur in cones)

• Rhodopsin (visual purple) is composed of the protein scotopsin and retinal or, equally well, retinol (Vitamin A). • Light energy decomposes rhodopsin into its two major components, scotopsin and retinal. • It is the formation of metarhodopsin II ("activated rhodopsin") that causes electrical changes in the rods that result in transmission of the visual image to the visual cortex in the CNS. • The all-trans forms of retinal and retinol are converted into the 11-cis forms by RETINAL ISOMERASE. • 11-cis retinal then automatically recombines with scotopsin to form rhodopsin. Thus, the cycle is complete. • Rhodopsin remains stable until its decomposition is again triggered by absorption of light energy. • Vitamin A is plentiful in the cytoplasm of rods and is also stored in large quantities in the liver. Chronic A-deficiency (months) causes "night blindness" which is quickly cured by injecting vit A.

14. What mechanisms are involved in anaphylactic shock?

• Severe allergic reaction • Histamine release (vasodilator) • Increase capillary permeability • Dilation of arterioles • More severe if fever is present - Skin blood vessels already dilated

Substances can enter or leave cells via CM under certain conditions, which involve the following mechanisms:

• Simple diffusion • Facilitated diffusion (carrier-mediated) • Active transport (carrier-mediated, energy-dependent)

Two ways to stop the decompnesation process:

• Strengthening the heart by the administration of cardiotonic drugs (eg., dugitalis preparations which increase force of contraction with efficiency). • Administrating diuretics and reducing water and salt intake, which bring about a balance between fluid intake and output (despite low CO). In brief: re-establish normal fluid balance so that at least as much fluid leaves the body as it enters it.

structure of rods and cones

• The outer segments of the rods and cones are modified cilia made up of stacks of flattened saccules (cones) or disks (rods) both of which are composed of membrane. • The saccules and disks contain photosensive compounds, including rhodopsin (rods) and color-sensitive pigments (cones), that react to light and initiate action potentials in the visual pathways. • Rod outer segments are being constantly renewed by formation of new disks and phagocytosis of old disks from the outer tip by cells of the pigment epithelium. • Cone renewal is a more diffuse process and appears to occur at multiple sites in the outer segments.

7. How does atherosclerosis cause ischemic heart disease?

• This is a common cause of death. • It results from insufficient coronary blood flow due to various causes. • Most frequent cause of diminished coronary flow is atherosclerosis (results from development of atherosclerotic plaques that protrude into vessel lumens and either block or partially block blood flow). • Atherosclerotic plaque can cause local blood clot called thrombus, which can grow and occlude the artery. • Occasionally, the clot breaks away and flows to another site and blocks the artery at a more distant point. Such thrombus is called embolus (process: embolism).

6. Describe the factors that increase cardiac output during heavy exercise.

• When local tissue vessels dilate and attempt to increase CO above normal, the nervous system plays an important role in preventing the arterial pressure from falling too low (reflexively). This helps maintain high CO. - In exercise, the nervous system provides additional signals to raise arterial pressure above normal, which serves to increase CO (extra 50-100%). - Exercise increases skeletal muscle metabolic rate leading to relaxation of bv and increase in oxygen supply. This decreases arterial pressure, but reflex mechanism compensates by sending signals to VMC/brain which induces circulatory excitation: vasoconstriction, and increased heart rate and contractility, thus rising arterial pressure to allow increase in CO

Young-Helmholtz theory of color vision.

• Young-Helmholtz Theory: There are three kinds of cones each containing a different photo-sensitive pigment that is maximally sensitive to one of the three primary colors. • Perception of a particular color depends on the percent absorptions of the wavelength by the cones. For example, a monochromatic orange light stimulates red cones to a value of 99% and green cones to a value of 42%. It does not stimulate blue cones at all. The ratios of stimulation of the three types of cones are 99:42:0. The nervous system interprets this set of ratios as the sensation of orange. A monochromatic blue light stimulates blue cones to a value of 97% but does not stimulate green or red cones at all. The ratios of stimulation are 0:0:97 which is interpreted by the nervous system at blue. -For example, when we see orange, it is because the red cones are 99% stimulated, and the green cones are 42% stimulated. This overlap in cones = orange

Young-Helmholtz theory of color vision.

• Young-Helmholtz Theory: There are three kinds of cones each containing a different photo-sensitive pigment that is maximally sensitive to one of the three primary colors. • Perception of a particular color depends on the percent absorptions of the wavelength by the cones. For example, a monochromatic orange light stimulates red cones to a value of 99% and green cones to a value of 42%. It does not stimulate blue cones at all. The ratios of stimulation of the three types of cones are 99:42:0. The nervous system interprets this set of ratios as the sensation of orange. A monochromatic blue light stimulates blue cones to a value of 97% but does not stimulate green or red cones at all. The ratios of stimulation are 0:0:97 which is interpreted by the nervous system at blue. -For example, when we see orange, it is because the red cones are 99% stimulated, and the green cones are 42% stimulated. This overlap in cones = orange

mechanism of accommodation of the eye and its loss in prebyopia. What division of the autonomic nervous system of which cranial nerve is responsible for accomodation?

...The mechanism of accomodation depends on the properties of the LENS - The lens is a strong elastic capsule, and when there is no tension on it (nothing is pulling on it, such as when it is taken out of the body) it becomes a SPHERE. - Inside the eye, the lens has suspensory ligaments that attach it to the cilliary body. These very inelastic ligaments pull the lens almost flat in the normal, resting eye. - On the ciliary body is the cilliary muscle. When this muscle contracts, it pulls the ligaments forward and medially. This reduces the tension on the lens. - When tension is reduced, the lens becomes more sperical (more convex) and therefore its refractive power increases -Increased refractive power lets us see things clearly up close -The refractive power of the lens can increase (in children) by up to 14 additional diopters -Presbyobia ** Important ** -As a person ages, their lens becomes larger, thicker, and less elastic. It can no longer change shape as readily. (If it were taken out of the body, it would NOT automatically become spherical) -This is due to the proteins in the lens becoming denatured over time -Presbyopia is a condition which the lens does not accomadate. It remains focused at one distance. -So, as we age, the closest distance that we can focus gets farther and farther away Age Focusing distance 10 8cm 20 10cm 30 12 cm 40 18cm 50 52cm ** The big change is here, between 40 and 50 ** 60 83cm 70 100cm -Autonomic control- ** Important ** -Accommodation is accomplished by the parasympathetic nervous system. The preganglionic cell bodies originate in the Edinger-Westphal nucleus. The fibers travel on cranial nerve 3 (occulomotor), and are associated with the cilliary ganglion (see anatomy notes for more information)

15. Define diffusion, osmosis and reflection coefficient.

...diffusion - movement of molecules in liquid or gas from high to low concentration (passive) osmosis - movement of H2O from high to low [] gradient

3. What regulates "sympathetic tone?" What are the inherent properties of the vasomotor center?

..The vasomotor center sends signals continuously to the sympathetic vasoconstrictor nerve fibers throughout the body, causing slow firing of these fibers and this is called sympathetic vasoconstrictor tone ('background' or 'basal tone'). These impulses maintain a partial state of vascular contraction (called vasomotor tone). Figure 18-4 demonstrates the significance of vasoconstrictor tone, experimentally.

The osmole expresses concentration in terms of # of particles. 1 osmole= ?

1 gram molecular wt of undissociated solute (eg., 180 gram of glucose= 1 osmole of because it does not dissociate)

15. List the three stages of gastric secretion.

1) cephalic- before food enters stomach (20% of secretion) 2) gastric- when food enters stomach (70%) 3) intestinal phase- when food enters duodenum (10% of secretion

List two basic processes which may establish membrane potentials.

1) establishment of a diffusion potential across a cell membrane caused by potassium ions diffusing from inside the cell to the outside through a membrane that is selectively permeable only to potassium 2)establishment of a diffusion potential when the membrane is permeable only to sodium ions. (note that the internal membrane potential is negative when potassium ions diffuse and positive when sodium ions diffuse because of opposite concentration gradients of these two ions.

8. Outline four ways in which saliva functions to maintain health in the oral environment.

1) flow of saliva helps wash away pathogenic bacteria and food particles 2) bacteriocidal factors (lysozyme, thiocyanate, proteolytic enzymes) 3) contains antibodies that can destroy bacteria 4) (?) Cindy says- inhibits demineralization of teeth (1-3 were in the book

1. List the major functions of the secretions of the alimentary tract.

1- production of digestive enzymes 2- production of mucous, which lubricates and protects the GI

8. State the percentage of hypertension cases that are renal in origin.

1-5 % of hypertension

steps in the initiation and execution of muscle contraction

1. An action potential travels along a motor nerve to its endings on muscle fibers. 2. At each ending, the nerve secretes a small amount of the neurotransmitter substance acetylcholine. 3. The acetylcholine acts on a local area of the muscle fiber membrane to open multiple "acetylcholine- gated" channels through protein molecules floating in the membrane. 4. Opening of the acetylcholine-gated channels allows large quantities of sodium ions to diffuse to the interior of the muscle fiber membrane. This initiates an action potential at the membrane. 5. The action potential travels along the muscle fiber membrane in the same way that action potentials travel along nerve fiber membranes. 6. The action potential depolarizes the muscle membrane, and much of the action potential electricity flows through the center of the muscle fiber. Here it causes the sarcoplasmic reticulum to release large quantities of calcium ions that have been stored within this reticulum. 7. The calcium ions initiate attractive forces between the actin and myosin filaments, causing them to slide alongside each other, which is the contractile process. 8. After a fraction of a second, the calcium ions are pumped back into the sarcoplasmic reticulum by a Ca++ membrane pump, and they remain stored in the reticulum until a new muscle action potential comes along; this removal of calcium ions from the myofibrils causes the muscle contraction to cease.

Nitrogen excretion in urine is used to assess protein catabolism.

1. Average proteins contain 16% N. 2. 90% of metabolized N is excreted in urine (as urea, creatinine, uric acid). 10% is excreted in the feces. 3. By measuring 24-hour urinary excretion of N the 24-hour breakdown of protein can be estimated. 4. Excretion of 8 g N in urine/day means ~55 g of protein were catabolized (8 g/day divided by 0.16 g N/g of protein + 10%). 5. If daily intake of protein is less than daily breakdown, the person is in negative N balance, meaning body stores of protein are decreasing daily.

8. What 2 general factors cause decreased cardiac output?

1. Cardiac abnormalities that decrease the ability of heart to pump blood (cardiogenic/cardiac shock). - myocardial infarction - toxic state of the heart - severe vlavular dysfunction - heart arrhythmias, etc. 2. Factors that decrease VR - diminished blood volume - decreased vasomotor tone - obstruction of blood flow • Abnormalities that cause pumping ability of heart to fall too low (due to severe damage) • Those that cause venous return to fall too low (any factor that interfere with VR, such as decreased blood volume and acute venous dilatation).

Special mechanisms for acute blood flow control in specific tissues

1. Control of blood flow in the kidneys is vested largely in the tubuloglomerular feedback, in which the composition of the fluid in the early distal tubule is detected by an epithelial structure of the distal tubule known as the macula densa (located adjacent to the afferent and efferent arterioles at the nephron juxtaglomerular apparatus). When too much fluid filters from the blood via the glomerulus, feedback signals from the macula densa cause constriction of the afferent arterioles, reducing both renal blood flow and glomerular filtration rate back to normal. . 2. In the brain, the concentrations of carbon dioxide and hydrogen ions play prominent roles in the control of blood flow, in addition to oxygen. Cerebral vessel dilatation caused by an increase of either or both of these allows rapid washout of the excess carbon dioxide or hydrogen ions from the brain tissues. This is significant because the excitability of the brain itself is highly dependent on exact control of the amounts of both substances. 3. Blood flow control in the skin is closely linked to regulation of body temperature. Cutaneous and subcutaneous flow regulates heat loss by metering the flow of heat from the core to the surface of the body. Skin blood flow is controlled largely by the CNS via the sympathetic nerves. Although skin blood flow is only ~ 3 ml/min/100 g of tissue in cool weather, large changes can occur as needed, depending on the temperature of the environment (expressed by inverse relationship). It should be noted that even with severe vasoconstriction, skin blood flow is usually great enough to meet the basic metabolic requirements of the skin.

Possible causes of low-resistance shock

1. Deep general anesthesia (depresses VMC) 2. Spinal anesthesia (blocks symp outflow) 3. Brain damage (vasomotor paralysis) • Maybe neurogenic (no loss of blood volume). • Massive vasodilation of vein due to sudden loss of vasomotor tone. • Could happen in response to strong emotion and leads to fainting

quantitative differences between muscle AP and nerve AP (nerve AP's were discussed in Chap. 5)

1. Resting membrane potential: about -80 to -90 millivolts in skeletal fibers—the same as in large myelinated nerve fibers. 2. Duration of action potential: 1 to 5 milliseconds in skeletal muscle—about five times as long as in large myelinated nerves. 3. Velocity of conduction: 3 to 5 m/sec—about 1/13 the velocity of conduction in the large myelinated nerve fibers that excite skeletal muscle.

Arcuate nuclei of hypothalamus is activated by several hormones from the GI tract and fat cells that act to regulate food intake and energy expenditure.

1. The arcuate nuclei sense blood levels of: a. leptin - from fat cells b. CCK - from fat entering duodenum c. insulin - from pancreatic β-cells d. peptide YY - from small and large intestines ...which stimulate the arcuate nuclei to cause activation of POMC (pro-opiomelanocortin) neurons to secrete a-melanocyte-stimulating hormone (a-MSH) together with cocaine and amphetamine-related transcript (CART) that are anorexigenic substances that inhibit feeding.

Feedback Mechanisms for Control of Food Intake

1. The hypothalamus receives neural sensory information from the GI tract (via vagus nerve) that relates to stomach filling. 2. It senses blood levels of glucose, FFA, AA. 3. Increased blood levels of leptin (proportionate to amount of stored fat) inhibit feeding while those of ghrelin (from parietal cells of stomach) stimulate feeding. They rise during fasting, fall after eating. 4. Peptide YY (PYY) - secreted by ileum and colon in response to fatty foods. It tends to inhibit feeding. 5. Receives cerebral information regarding sight, smell, taste of foods to stimulate feeding. 6. CCK blood levels from fat in duodenum inhibits feeding.

activation of smooth muscle contraction

1. calcium ions enter and bind to calmodulin (smooth muscle has no troponin) 2. calmodulin-Ca activates myosin kinase, a phosphorylating enzyme 3. one light chain on each myosin (called the regulatory chain) becomes phosphorylated by ATP + myosin kinase

10. List the four primary factors that determine fluid movement through the capillary membrane (these are the so-called "physical factors" or "Starling factors").

1. hydrostatic pressure inside capillaries 2. interstitial pressure (opposes hydrostatic pressure) 3. plasma colloid osmotic pressure 4. interstitial fluid colloid osmotic pressure

16. State the most important function of the lymphatic system.

1. provide route for return of plasma proteins to blood stream 2. control volume of interstitial fluid 3. control interstitial fluid presure

The formation and release of acetylcholine at the NMJ occur in the following stages:

1. vesicles (empty) are formed by the golgi in the axon cell body located in the spinal cord then transported by axoplasm all the way to the NMJ at the tips of the peripheral nerve fibers (about 300,000 of these collect in the nerve terminals of a single skeletal muscle end plate. 2. Ach is made in the cytosol of the nerve fiber and packed into the awaiting vesicles (10,000 Ach per vesicle) 3. AP causes voltage gated calcium channels in membrane of nerve terminal to open, allowing an influx of calcium to 100-fold the original concentration, which in turn increases the rate of fusion of the acetylcholine vesicles with the terminal membrane about 10,000-fold and exocytosis of Ach into the synaptic space. Then, after a few milliseconds, the acetylcholine is split by acetylcholinesterase into acetate ion and choline, and the choline is reabsorbed actively into the neural terminal to be reused to form new acetylcholine. (all in 5-10 milliseconds) 4. Ach regeneration: Within a few seconds after each action potential is over, "coated pits" appear in the terminal nerve membrane, caused by contractile proteins in the nerve ending, especially the protein clathrin, which is attached to the membrane in the areas of the original vesicles. Within about 20 seconds, the proteins contract and cause the pits to break away to the interior of the membrane, thus forming new vesicles. Within another few seconds, acetylcholine is transported to the interior of these vesicles, and they are then ready for a new cycle of acetylcholine release.

cessation of contraction-role of myosin phosphatase

1. when intracellular calcium ion concentration falls below a critical level (due to Ca-pump), everything reverses 2. myosin phosphatase then splits phosphate from the regulatory light chain and contraction stops

1. With regard to acute glomerular nephritis, state: the type of disease which usually precedes the disorder; the age group which is most often affected; the changes in the structure, number and permeability of the glomeruli; the prognosis of the disease.

1.With regard to acute glomerular nephritis, state: the type of disease which usually precedes the disorder; failure caused by an abnormal immune reaction to Strep. infection the age group which is most often affected; the changes in the structure, number and permeability of the glomeruli; - Glomeruli- many become blocked, but the epithelium also becomes "leaky" to plasma proteins. This causes nephrotic syndrome (see BO #6). The glomerular epithelial cells begin to proliferate the prognosis of the disease. - usually, this inflammation subsides after 2 weeks, and kidney function returns to normal. Sometimes, the glomeruli are damaged beyond repair.

normal intraocular pressure

10 to 20 mm Hg *Other places in the body that have positive pressures are- CSF (cerebrospinal fluid), bone marrow, kidney, and the pulp!. Positive pressure in the eye is important because it keeps the retina plastered up against the wall of the eye

NMJ fatigue is rare under normal circumstances, but it can set in when the number of acetylcholine vesicles is increasingly diminished by strenuous stimulation and impulses fail to pass into the muscle fiber. NMJ fatigue might occur at what kind of rate for how long?

100 times per second for several minutes

know normal blood glucose concentration

100mg/100mL

3. Define basal metabolism and describe the standard conditions necessary for the measurement of the basal metabolic rate.

2- Basal Metabolism- the bare minimum energy that must be expended by the body to keep vital functions going. - The normal basal metabolic rate (BMR) is 35kcal/m2/hr. -specific dynamic action- carbohydrates and fats raise the BMR ~4% due to digestion processes, but high protein meals can increase it by 30% for several hours -thyroid dysfunction- BMR= 50% of normal to 200% of normal (depends on hyper or hypo thyroid dysfunction -neural stimulus- sympathetic stimulation ↑ BMR - A persons BMR is measured by O2 consumption in a very controlled environment. Then, if the BMR comes out to be abnormal, you try to figure out why. Standard conditions: restful nights sleep, no exercise, no food for 12 hours, reclined position, 68-80F, relieve all emotional stresses

clinical method for stating visual acuity. Does 20/40 mean you can twice as well or half as well as normal?

20/20= normal vision (this means that you can see an object clearly at 20 feet that a "normal" person could see at 20 feet 20/200= BAD vision (you can see an object clearly at 20 feet that a "normal" person could see at 200 feet!!! 20/40= vision that is half as good as normal 20/15= super sight

17. List the three major components of the defense system which protects against deviations in extracellular fluid pH. State which of these is the most rapid, the slowest, the one with the highest gain.

3 defense systems for when the ECF pH is challenged: 1- chemical buffers (fastest, but limited capacity) 2- CO2 removal by lungs (rapid, but low gain) 3- bicarbonate reabsorption and H+ secretion by kidneys (slower, but highest gain) * I am assuming that "gain" here means that it is efficient... ie, a little goes a long way.

16. State the normal osmolarity of the body fluids.

300 mosmol/L...

Wavelengths of visible light:

397-723 nm.

five causes of obesity.

5 causes of obesity (I could only find 4 general categories in the book) 1-PSYCHOGENIC- we are taught to eat three big meals a day, clean our plates, we need dessert. Also eating as a response to emotion or stress can lead to obesity 2- GENETIC FACTORS (twin studies) Twins who were separated at birth tend to end up about the same weight as adults 3. GENETIC ABNORMALITY in the feeding center (won't shut off) 4. GENETIC FAT STORAGE/MOBILIZATION problem 5.CHILDHOOD OVER-NUTRITION - the number of fat cells we have as children stay constant through the rest of our lives. Children who are overnourished make a lot more fat cells, and then have to carry those cells with them throughout life. This type of obesity is harder to treat then obesity that comes on at middle age (because then you are simply making the fat cells you have bigger) 4- genetic distribution of fat cells (?)

4. List the body's responses to lowered and to elevated ambient temperatures under high and under low relative humidities.

5-Exercise- increases BMR (Table 72-1) ** Climbing stairs increases BMR more than any other exercise ** 6- Shivering- body is attempting to increase temperature by increases muscle activity, this ↑ BMR 7- Vasoconstriction of skin 8- Blood flow- helps conserve or dissipate heat, depending on whether blood returns via superficial veins (closer to skin- loses heat) or via venae comitantes -Deep veins that run in close proximity to arteries can help the blood get warm again on its return trip to the heart. As it passes the arterial blood (which is warm), some of the heat transfers to the cool venous blood, warming it up. This is a countercurrent system C- Heat Loss 1-Sources- Conduction- heat transfered directly from body to another object (not much heat is lost this way); Convection- Heat lost to the air and then carried away; Radiation- Infrared heat rays radiating from body; Evaporation- 0.58 kcal of heat lost for every gram of water that evaporates off of our skin 2- Factors effecting heat transfer- a-skin- goosebumps- increases surface area b-thermal gradient c- surface area- -exposure of vascular bed- the more surface area that is exposed, the more heat will be lost to convection -vasodilation/vasoconstriction- changing the amount of blood that reaches the surface area- effects how much heat can be lost - insulation- more clothing decreases surface area available for heat loss - wind chill- increased convection 3- Heat loss by sweating: Effected by: a- amt. of sweat and area exposed - more sweat and more area = more heat lost b- rate of movement of air- increased convection= increased heat lost c- relative humidity- less water can evaporate when humidity is high d- salt loss- with exercise you can lose ~20g/day 4- panting- ** EXAM Q *** Why is acid base balance not effected with panting? - In panting, the air only travels over the mouth and superficial airways, it does not reach the lungs where gas exchange occurs. Therefore, the dog doesn't lose too much CO2. 5- Environmental temperature- see chart in handout!!! Temperature range 0-10= zone of hypothermia (the body cannot regulate its body temperature B-D (37-50)= neutral zone- the BMR is stable D-E= zone of hyperthermia

1. List the sources of energy for muscle work and relate these to aerobic and anaerobic metabolism.

A - Immediate sources- There is a small amount of ATP stored in the muscle at any given time. (not much though) This ATP is used up very quickly when it is hydrolyzed by myosin ATPase activity (It also helps re-sequester Calcium into the sarcoplasmic reticulum) -Phosphocreatine provides a short term reserve of energy -Enzyme= CPK- one form of the enzyme is in the mitochondria, and a different form is in the muscle. - When ATP is abundant, phosphocreatine is made to store some of the energy. When the energy is getting used up, the phosphate is cleaved off to make more ATP B- Ultimate Sources of Energy Aerobic metabolism- oxidative phosphorylation Anaerobic metabolism- pyruvate → lactic acid Glycogen→ glucose→ pyruvate, and the oxidation of free fatty acids also provides energy (ATP) C- Ultimate fate of Energy- All energy is eventually converted to heat -motion and friction within the body produce heat. Temperature can effect the rate of chemical reactions, heat can increase some body functions. -One critical factor in homeostasis is our ability to dissipate heat when we use energy

4. What are ectopic beats in terms of the heart rate, what produces them?

A pacemaker elsewhere than the sinus node is called an "ectopic" pacemaker. An ectopic pacemaker causes an abnormal sequence of contraction of the different parts of the heart and can cause significant debility of heart pumping. could occur in the A-V node or purkinje fibers

Define osmosis.

A process of net movement of water caused by concentration difference of water across membrane.

What event produces the incisura or dicrotic notch in the aortic pressure curve?

A so-called incisura occurs in the aortic pressure curve when the aortic valve closes. This is caused by a short period of backward flow of blood immediately before closure of the valve, followed by sudden cessation of the backflow.

types of AP observed in smooth muscle

A, Typical SM action potential (spike potential) elicited by an external stimulus. B, Repetitive spike potentials, elicited by slow rhythmical electrical wave that occur spontaneously in the SM of the intestinal wall. C, Action potential with a plateau, recorded from a SM fiber of the uterus.

long vers. short term regulation of food intake

A. Nutritional regulation (long-term) 1. glucostatic theory 2. amino acid theory 3. lipostatic theory B. Alimentary regulation (short-term) 1. gastrointestinal filling 2. GI hormones (CCK, peptide YY) 3. oral "metering" of food

achlorhydria and pernicious anemia that may develop as a result of gastric atrophy associated with chronic gastritis or as a result of gastrectomy.

ACHLORHYDRIA- failure of the stomach to secrete HCl ​pepsin is not secreted or it is not functional causes reduced (or no) activity of the stomach, BUT overall digestion is not severely effected because trypsin can pick up the slack -PERNICIOUS ANEMIA- intrinsic factor is not produced. Normally intrinsic factor binds to Vit B12, and protects it from being degraded in the stomach before it can be absorbed, Without it, No Vitamin B12 is absorbed. BAD

achlorhydria and pernicious anemia that may develop as a result of gastric atrophy associated with chronic gastritis or as a result of gastrectomy.

ACHLORHYDRIA- failure of the stomach to secrete HCl; pepsin is not secreted or it is not functional causes reduced (or no) activity of the stomach, BUT overall digestion is not severely effected because trypsin can pick up the slack -PERNICIOUS ANEMIA- intrinsic factor is not produced. Normally intrinsic factor binds to Vit B12, and protects it from being degraded in the stomach before it can be absorbed, Without it, No Vitamin B12 is absorbed. BAD

Define action potential, depolarization and repolarization.

AP - rapid changes in the membrane potential that spread rapidly along the nerve fiber membrane. depolarization - cell becomes more positive repolarization - cell returns to resting negative membrane potential

what is the source of energy for contraction; for the chemical evens in the motion of the myosin head

ATP

Acute or chronic spasm of ciliary muscle. Compromises lens ability to accommodate for close-up vision.

Accommodation spasm:

5. Describe the vasodilator theory of local blood flow regulation.

According to the vasodilator theory, the greater the rate of metabolism or the less the availability of oxygen or some other nutrients, the greater the formation of vasodilator substances in the tissue cells. The substances then diffuse through the tissues to the precapillary sphincters, metarterioles, and arterioles to cause dilation. Examples include adenosine, carbon dioxide, adenosine phosphate compounds, histamine, potassium ions, and hydrogen ions.

acetylcholine receptor and associated channel on SKM fiber

Acetylcholine channel. A) Closed state. B) 2 acetylcholine (Ach) attach to the two alpha subunits of the channel causing a conformational change which opens the gate to allow sodium ions to enter the muscle fiber and excite contraction.

13. Describe the mechanism whereby acetylcholine is degraded.

Ach degradation: Once Ach is released into a synaptic cleft, you do not want it hanging around for a really long time, because you don't want the stimulation of the next cell to last longer than the original stimulus -Ach is degraded by ACETYLCHOLINESTERASE. The enzyme is located IN the cell membrane of the cell, adjacent to Ach receptors.

Name the major neurotransmitters at each of the following b. autonomic ganglia;

Ach- It is VERY IMPORTANT to remember this KEY difference between the somatic nervous system and ANS. The somatic system has ONE neuron that does its job. It does not have to synapse with a second neuron along its way. The ANS DOES synapse with another cell body (in a ganglion) The neurotransmitter used at this junction is ALWAYS Ach. (for symp. and parasymp. both)

two phases of local blood flow control

Acute control - Accomplished by rapid changes (sec-min) in dilation or constriction of small bv and capillaries, providing rapid flow maintenance. -example is increased blood flow in skeletal muscle during exercise -decreased oxygen availability increases tissue blood flow Long-term control - Slow changes in flow over a longer time (days-even yrs). - This mostly provides better control of flow proportional to needs of tissues. - Occurs mainly due to ↑ or ↓ physical size and # of supplying bv.

13. What long-term mechanisms operate to compensate for chronic cardiac failure?

After a short period of heart attack, prolonged secondary effects occur (1) retention of fluid and (2) progressive recovery of heart itself over several weeks to months. • ↓CO reduces urinary output. If heart is not greatly damaged, this effect has the tendency to increase fluid retention, thereby ↑VR and CO and improving heart pumping function. Point D in Fig reflects this situation, which represents normal CO of 5L (thus, normal renal output, followed by reduced fluid retention). • However, if the heart maximum ability to pump is reduced still more, blood flow to kidney becomes permanently too low and fluid retention indefinitely continues, unless intervened with therapy. • This can lead to edema formation with detrimental effects: - overstretching of heart (congestion of heart), further heart weakening, filtration of fluid into lungs (pulmonary edema), deoxygenation of blood, excessive edema all over, etc.

influence of gastric distension and of "head receptor metering" on feeding activity.

Alimentary regulation of feeding (short term regulation) -gastric distention- when your stomach is full, you lose the urge to continue eating -"head receptor metering"-all of the sense cues that go along with eating (smell, taste, texture, the action of chewing, etc) stimulate the satiety center as well. Example- the dog experiment- when a dog's esophagus was ligated and pulled out of his neck (so that everything he ate ended up falling straight to the floor) he STILL stopped eating after a few minutes. Even though there were no gastric distention cues to tell him to stop.

Nyctalopia:

Also called "night blindness." Due to diets deficient in beta-carotene or vitamin A itself. Results in progressive loss of rod function. Cured by dietary changes (green leafy vegetables, yellow or orange fruits and vegetables) or by injections or vitamin A.

11. What is angina pectoris? How is it caused, how is it treated? pharmacologically and surgically?

Angina pertoris is cardiac pain caused by an imbalance between load of the heart and the availability of coronary blood flow (insufficient). • Pain is usually felt under the upper sternum over the heart and most commonly in left arm and shoulder, etc. These areas receive pain fibers from the same spinal cord segment as the heart. • Pain could be due to release of lactic acid and other pain- promoting products (histamine, kinin) from the ischemic heart tissue to stimulate pain endings in cardiac muscle.

3. List the two factors which determine the long-term arterial pressure level.

Angiotensin II causes the kidneys to retain both salt and water in 2 ways: (1) by acting directly on the kidneys to cause salt and water retention, and (2) by causing the adrenal glands (cortex) to secrete aldosterone, which in turn increases salt and water reabsorption by the kidney tubules. Hence, with excess angiotensin II, the entire long-term renal-body fluid mechanism for arterial pressure control automatically becomes set to a higher arterial pressure level. Angiotensin II constricts the renal arterioles, thereby diminishing blood flow, and the slow flow of blood reduces the pressure in the peritubular capillaries, which in turn causes rapid reabsorption of fluid from the tubules. Angiotensin II's direct effects on the tubular cells increases tubular reabsorption of sodium and water. The overall result is significant- sometimes decreasing urine output to ~1/5th of normal. Angiotensin II stimulates aldosterone secretion powerfully and when the RAS becomes activated, the rate of aldosterone secretion by the adrenal gland usually increases (causing marked increase in sodium reabsorptions, thus increasing the total body EC fluid sodium; the increased sodium causes water retention, increasing the EC fluid volume and leading secondarily to still more long-term elevation of the arterial pressure). Therefore, both the direct effect (more potent) of angiotensin on the kidney and its effect through aldosterone are important in long- term arterial pressure control.

disorder characterized by a disturbed sense of body image, a morbid fear of obesity, a refusal to maintain a minimally normal body weight, and amenorrhea. 95% female, onset at adolescence. There are no dental consequences because they do not vomit.

Anorexia nervosa

Right and left ventricular volume output curves

Approximate normal right and left ventricular volume output curves for the normal resting human heart as extrapolated from data obtained in dogs and data from human beings. • As the right and left atrial pressures rise, respective ventricular outputs/min also increases

9. What is essential hypertension? What are the possible mechanisms? How is it treated?

Approximately 90-95 % of the people who have hypertension are said to have this form of CV disorder. The majority of patients with hypertension are overweight, and studies suggest that excess weight gain and obesity may account for as much as 65-75 % of the risk for developing primary/essential hypertension. Clinical guidelines for treating hypertension recommend increased physical activity and weight loss as a first step in treating most patients with hypertension. Some of the characteristics in this regard include the following: 1. Increased cardiac output partly due to additional blood flow required for the extra adipose tissue. As the hypertension is sustained for many months and years, TPR may increase. 2. Increased sympathetic nerve activity, especially in the kidneys. The causes of increased sympathetic activity in obesity are not fully understood, but it has been suggested that hormones (eg., leptin) released from fat cells may directly stimulate the hypothalamus, which, in turn, has an excitatory influence on the vasomotor centers. 3. Increased angiotensin II and aldosterone levels. This may be caused partly by increased sympathetic nerve stimulation, which increases renin release by the kidneys and therefore formation of angiotensin II, which, in turn, stimulates the adrenal gland to secrete aldosterone. 4. Impairment of the renal-pressure natriuresis mechanism, and inadequate salt and water excretion by the kidneys (unless the arterial pressure is high or unless kidney function is improved). Chronic reductions in arterial pressure with effective antihypertensive therapies usually do not cause marked salt and water retention as these therapies also improve renal- pressure natriuresis. Briefly, impaired renal-pressure natriuresis in obesity hypertension is caused mainly by increased renal tubular reabsorption of salt and water due to increased sympathetic nerve activity and increased levels of angiotensin II and aldosterone. However, if hypertension is not effectively treated, there may also be vascular damage in the kidneys that can reduce the glomerular filtration rate and increase the severity of the hypertension.

production and movement of aqueous humor through the eye

Aqueous humor- lies in front and to the sides of the lens -Formation of aqueous humor- Fluid secreted by the ciliary processes (folds projecting from the ciliary body) Produces 2-3 uL/minute. -The aqueous humor is a free flowing liquid (unlike vitreous humor, which is a gel-like mass) -This fluid normally drains out of the eye into the canal of Schlemm

production and movement of aqueous humor through the eye and list normal and elevated intraocular pressures and the causes of glaucoma.

Aqueous humor- lies in front and to the sides of the lens -Formation of aqueous humor- Fluid secreted by the ciliary processes (folds projecting from the ciliary body) Produces 2-3 uL/minute. -The aqueous humor is a free flowing liquid (unlike vitreous humor, which is a gel-like mass) -This fluid normally drains out of the eye into the canal of Schlemm

16. State the normal pH values of arterial blood and venous blood. What accounts for the difference?

Arterial blood = 7.4 -Venous blood = 7.35. The difference is because venous blood has picked up a ton of CO2 from the tissues, so the ratio is off, and the pH ↓ * he also talked about the pH of intracellular fluid- it is lower, because the cell is producing CO2 and other acidic metabolic byproducts

what occurs as soon as the actin filament becomes activated by calcium ions?

As soon as the actin filament becomes activated by the calcium ions, the heads of the cross-bridges from the myosin filaments become attracted to the active sites of the actin filament, and this, in some way, causes contraction to occur.

Premature ventricular contractions (PVCs) demonstrated by the large abnormal QRS-T complexes (leads II and III).

Associated with a series of premature contractions alternating with normal contractions

Images are blurry due to lack of a uniform curvature of the cornea (like the surface of an egg lying on its side). Thus, there are two or more focal lengths.

Astigmatism:

what and what fuse at the end of a muscle fiber in order to insert into bone

At end of the fiber, surface layer of sarcolemma fuses with tendon fiber, which in turn forms muscle tendon and inserts into bones.

12. What is circus movement in terms of the depolarization of the heart? What 3 factors cause this?

Atrial flutter: Caused by circus movement in atria, the electrical signal traveling in one direction around and around; it causes a rapid rate of contraction; signals reach A-V node too rapidly, usually with 2-3 beats of atria for every beat of ventricle.

Average Content of a 70-Kilogram Man

Average Content of a 70-Kilogram Man

7. Describe the following three types of disorders which produce hyperthermia and give examples of each type: diminished heat dissipation

B- Diminished Heat Dissipation- 1- dehydration exhaustion- associated with heavy exercise If you are water deficient, you cannot lose more water through sweat, so your body does not dissipate enough heat symptoms- rapid pulse, edema 2- classic heat stroke- this is common in the urban poor, the elderly (during the summer, those who cannot afford air conditioning). This also occurs in infants, if the baby is 'overwrapped' symptoms are the same as exertional heat stroke treatment- cool and restore acid/base balance ** There is a 10% mortality rate for heat stroke even with treatment **

5. State which of the chemical buffers in blood has the greatest buffering capacity.

BICARBONATE is the most important buffer in the blood (and the rest of the ECF) This system will be discussed later in this chapter. -This buffer system is regulated by our bodies to keep our blood pH at 7.4!!

passage of light through the various layers of the retina to the rods and cones, the function of the fovea (pp. 637-639) and the position of the optic disk and blind spot.

BO #1-The layers of the retina- Remember that there are a LOT of layers in the retina that light has to travel through before it reaches the rods and cones. The book lists 10 layers total, with rods and cones beginning in the 9th layer. (We covered this in histology also) -Because of the distance that light has to travel through these cells, visual acuity is decreased (as it travels through this mass of cells, it is going through areas of different refractive power, and getting scattered, etc, so by the time the light reaches the rods and cones, it is not as "clear". -FOVEA CENTRALIS- This is the area at the center of the retina (If you are staring directly at an object that is in the center of your field of vision, these light rays are hitting the fovea. -In this small region, all of the other cell layers are pushed to the side, so light does not have to travel as far inside cells, so it is more "clear" when it hits the cones -This is the area where our visual acuity is the BEST -The fovea is composed completely of cones Rods vs. Cones -Rods= black and white vision- There are more rods in the periphery of the retina -cones = color vision (need lots of light to see color) -Since there are only cones in the fovea, and you need a lot of light to see color, you cannot see as well in the dark if you focus directly on an object. So, you should focus off to the side, and look at the object with peripheral vision. This will use the RODS instead, and you will be able to see clearly in dim light (although you can't see it in color) ** Exam Q ** Most of the cones are in the fovea, and the rods are at the periphery of the retina!! -optic disc and blind spot- about 15 degrees away from the fovea (toward the nose) there is a spot that is deficient in rods and cones. This is the "blind spot." The "optic disc" is the area in which this blind spot occurs.

structure and location of olfactory cells (pp. 678, 680) and how they are stimulated (p. 679) and the requirements of an odor producing substance to activate olfactory cells.

BO #10- Okay, he really didnt cover this one in class, so here's the skimmed version: There are about 100million olfactory cells in the epithelium of the nostrils. The ells have tiny cilia or 'olfactory hairs' that project into the nasal cavity. An odor producing substance binds to receptors on these hairs, stimulating the olfactory cells Requirements of a substance to activate olfactory cells (this he did cover) -volatile (diffuses into the air) -water soluble -slightly lipid soluble

7 primary odors and the affective nature of smell.

BO #11- 7 primary odors: Camphoraceous Musky Floral Pepperminty Ethereal Pungent Putrid Affective nature of smell- smell is more important than taste in the selection of food, it is thousands of times more sensitive than taste. Smell has much more of an effective quality of pleasant or unpleasant than taste does.

abnormal feeding behavior as a mechanism of obesity.

BO #12- Abnormal feeding behavior as a mechanism of obesity: Excess energy input (exceeds energy output) during the development of obesity, also too little exercise for the level of food intake.

describe how long total body carbohydrate stores can last in starvation and describe how the body maintains energy demands during starvation.

BO #13-Carbohydrate stores in the body (glycogen in the muscle and liver) last for LESS THAN A DAY when starving/fasting -Glycogen is not meant to act as a storage of calories, but as a buffer for blood glucose levels -The body maintains energy demands by first using the bodies fat stores, and then protein stores

13. State the source of pepsin, the factor(s) involved in its activation and its physiologic action. Do the same for trypsin, chymotrypsin and carboxypeptidase.

BO #13-Pepsin- Pepsinogen is secreted by chief cells, then is cleaved to form pepsin by HCl. Pepsin begins protein digestion, by breaking peptide bonds -Trypsin- Trypsinogen is secreted from pancreas, then is cleaved by enteropeptidase. Trypsin splits protein molecules into smaller polypeptides -Chemotrypsin- Chemotrypsinogen secreted by pancreas, cleaved by trypsin, cleaves peptides into smaller peptides - Carboxypeptidase- Procarboxypeptidase also from pancreas, cleaved by trypsin, removes carboxy-terminal residues from short peptides

function of Vitamin K.

BO #17- Vitamin K- Aids in blood coagulation -K is necessary for the body to produce a lot of clotting factors (prothrombin, 7,9, and 10) -K is formed in the intestines by bacteria and is found in leafy veggies, -Blood thinner medication (coumadin, etc) inhibit vitamin K -Patients on these meds have to be careful when having dental work done. Before extracting a tooth, you may give an injection of vitamin K, for example

functions of Vitamin D.

BO #18-Vitamin D - Increases calcium absorption from the gut. Activated by UV light in skin, first hydroxylation in liver, second in kidney. Most milk in U.S. contains added Vitamin D.

daily protein requirement for children and adults.

BO #2 For growing children (and pregnant or lactating women) = 1-1.5gm protein/kg body weight -For normal adults= 0.5gm protein/kg body weight (average adult needs 30gm protein/day. Think about how much protein is in a quarter pounder!) -Protein is continually broken down everyday - a process called obligatory protein loss - (enzymes, plasma proteins, mucous secretions) to the extent of 20-30 grams/day.

20. List the major effects of acidosis and of alkalosis on the body.

BO #20- major effects on body- not really discussed in class -Metabolic acidosis stimulates breathing center in the brain to increase ventilation - Resp. acidosis stimulates kidneys to excrete less bicarbonate -Metaobolic alkalosis- decrease ventilation - Resp. alkalosis- stimulates kidneys to excrete more bicarbonate

effects of Vitamin C deficiency. What enzyme requires vitamin C (as a cofactor)?

BO #20-Vitamin C deficiency= scurvy ; Failure of wounds to heal, increased capillary fragility, loosening of teeth due to poor quality collagen. Good sources are fruits, juices and vegetables. -Vitamin C is an essential cofactor for prolyl hydroxylase which promotes hydroxylation of proline to form hydroxyproline, an essential component of collagen.

3. List the most characteristic changes in the body fluids of patients with terminal renal failure.

BO #3- Changes in body fluids with renal failure: Fig 31-9 - when renal failure occurs, these body fluid changes begin within the first day - By Day 12 of no kidney function, you are on death's door - Almost all solutes increase in concentration in the blood (Na, K, H+, water, NPN (see BO 5) EXCEPT HCO3 - this decreases!!! - patient develpes metabolic acidosis (refer to Ch 30, BO #19)

How many times louder is a noise of 100 db than is the threshold for human hearing?

BO #3- Threshold for hearing= -70 dB at 2000Hertz. -Know that the dB scale of loudness is a logrithmic scale!! For every increase of one bel, there is a 10fold increase in loudness -a decibel is 1/10 of a bel, so for every 10 dB increase, there is a 10 fold increase in intensity -So, the difference in -70dB and 100dB (-7B to 10B) is 1017, or 100,000 trillion times the threshold for hearing

attenuation of sound by contraction of the stapedius and tensor tympani muscles (p. 664), i.e. the attenuation reflex.

BO #5- Attenuation of sound- In response to VERY loud sounds, the ear muscles act to protect you -The tensor tympani pulls the malleus inward, and the stapedius pulls the stapes outward. This makes the ossicle system very rigid, and unable to conduct the sound waves as well, making the sound quieter -This effect works best on low frequency sounds (below 1000cycles/sec) -So, the cochlea is protected against loud sounds -AND, you are better able to filter out low frequency background noise and focus on sounds above 1000 cycles/sec. ** EXAM Q *** Know that the tensor tympani is innervated by V, and stapedius by VII!!

6. Describe the distribution of the enteric nervous system, the myenteric plexus, Auerbach's plexus, the submucosal plexus and Meissner's plexus.

BO #6 and #7- Enteric nervous system- intrinsic nerve fibers in the GI. They can function independently (do not need outside stimulus). - myenteric plexus= Auerbach's plexus: located between longitudinal and circular layers, is longitudinal/linear... travels the entire length of the GI Controls motility down the entire length of the gut. Action: increases intensity and frequency of rhythmic contractions, increses conduction of excititory waves -submucosal plexus = Meisner's plexus: between mucosa and circular layers. Effects minute sections of the gut, one at a time. Controls local secretion, absorption, and contraction of submucosal muscle.

7. State the physiologic functions of the plexuses listed in item 6.

BO #6 and #7- Enteric nervous system- intrinsic nerve fibers in the GI. They can function independently (do not need outside stimulus). - myenteric plexus= Auerbach's plexus: located between longitudinal and circular layers, is longitudinal/linear... travels the entire length of the GI Controls motility down the entire length of the gut. Action: increases intensity and frequency of rhythmic contractions, increses conduction of excititory waves -submucosal plexus = Meisner's plexus: between mucosa and circular layers. Effects minute sections of the gut, one at a time. Controls local secretion, absorption, and contraction of submucosal muscle.

"hunger", "appetite" and "satiety."

BO #7- hunger= craving for food - Appetite= craving for a specific food- appetite regulates the quality of food intake. In animals, it corrects nutritional deficiencies -Example- Na deficient rats will choose to drink NaCl water over KCl or glucose water. - Satiety= feeling of fulfillment- the opposite of hunger

cranial nerves that carry the sensation of taste to the tractus solitarius, and there flex centers for control of salivary gland function (p. 678).

BO #8- The tractus solitarius is the area in the brainstem where all of the taste fibers synapse before heading into the brain Facial nerve (VII)- carries taste fibers from the anterior 2/3 of the tongue (via chorda tympani) Glossopharyngeal (IX)- taste fibers from posterior 1/3 of tongue Vagus (X)- taste fibers from base of tongue and pharynx After these fibers get to the tractus solitarius, they send signals to the inferior and superior salivatory nuclei- this controls the function of the parotid, sublingual, and submandibular glands

glucostatic and lipostatic theories of the regulation of feeding. What is leptin? How might it alter hunger?

BO #9- Nutritional regulation of feeding Glucostatic and lipostatic- theories state that there are "thermostats" for glucose and fats, that tell you when you should eat. This is how the body regulates its food intake over the long term Leptin- Covered in very tiny detail- I don't think he expects us to memorize it on that level- here are the main points: -Leptin (or Ob) is secreted by adipose cells -The leptin travels to the ventromedial nucleus of hypothalamus (satiety center) and binds to a membrane receptor there (Db) -In obese people, Leptin is overproduced, and there is not enough Db in the brain to respond appropriately to this level of signal -When leptin is secreted and bound to its receptor: -↓ food intake -↓ production of neuropeptideY -↑ metabolism by secretion of NE to adipose tissue -↑ production of UCP (uncoupling protein, like in brown fat)- generates heat instead of ATP -In mice- When leptin was administered- the mice lost 22% of their body weight in 28 days.

structure and location of taste buds. (p. 676).

BO #9- Structure and location of taste buds- Structure- (not really discussed in class) ~50 modified epithelial cells- taste cells, that are centered around a taste pore. Each cell has taste "hairs" (microvilli) projecting into the pore. These taste cells interact with taste nerve fibers, which transmit the taste signals Location- 1) walls that surround the circumvallate papillae, 2) on the filliform papillae, 3) on the fungiform papillae. -some additional taste buds are on the palate, tonsilar pillars, epiglottis, and proximal esophagus

structure and location of taste buds. (p. 676).

BO #9- Structure and location of taste buds- Structure- (not really discussed in class) ~50 modified epithelial cells- taste cells, that are centered around a taste pore. Each cell has taste "hairs" (microvilli) projecting into the pore. These taste cells interact with taste nerve fibers, which transmit the taste signals Location- 1) walls that surround the circumvallate papillae, 2) on the filliform papillae, 3) on the fungiform papillae. -some additional taste buds are on the palate, tonsilar pillars, epiglottis, and proximal esophagus

6. Describe the functional anatomy of baroreceptor regulatory mechanism for maintaining normal blood pressure. How do the receptors respond to changes in arterial pressure?

Baroreceptors nerve endings lie in the walls of arteries and are stimulated when stretched. A few them are located in the wall of almost every large artery of the thoracic and neck; but they are generally abundant in the wall of the internal carotid artery just above the carotid bifurcation (called carotid sinus), and the wall of the aortic arch. Figure 18-5 illustrates that transmission of signals from the "carotid baroreceptors", through small Hering's nerves, to the glossopharyngeal nerves in the neck, and then to the tractus solitarius in the medulla of the brain stem. Messages from the "aortic baroreceptors" in the arch of the aorta are transmitted via the vagus nerves to the tractus solitarius of the medulla.

7. How do the baroreceptors function with changes in body posture? What is their buffer function?

Baroreceptors' ability to maintain constant arterial pressure in the upper body is significant when a person stands up after having been lying down. Arterial pressure in the head and upper part of the body fall immediately on standing, and marked reduction of this pressure could cause loss of consciousness. However, the pressure fall at the baroreceptors elicits an immediate reflex, which results in sympathetic discharge in entire the body, minimizing the decrease in pressure in the head and upper body. Since the baroreceptor system opposes either increases or decreases in arterial pressure, it is known as a pressure buffer system and the nerves are called buffer nerves. Figure 18-8 (above left) shows the importance of the buffer function of the baroreceptors in dog. Figure 18-9 (above right) depicts the frequency distributions of the mean arterial pressures recorded for a 24-hour day in both the normal dog and the denervated dog. In the absence of the arterial baroreceptor system, extreme variability of pressure are observed. In brief, a primary purpose of the arterial baroreceptor system is to reduce the variation in arterial pressure (up and down) to about one-third that which would occur if the baroreceptor system was not functioning.

Skeletal Muscle Tone.

Because normal skeletal muscle fibers do not contract without an action potential to stimulate the fibers, skeletal muscle tone results entirely from a low rate of nerve impulses coming from the spinal cord. These, in turn, are controlled partly by signals transmitted from the brain to the appropriate spinal cord anterior motoneurons and partly by signals that originate in muscle spindles located in the muscle itself.

Low-voltage electrocardiogram following local damage throughout the ventricles caused by previous myocardial infarction (which is accompanied by diminished muscle mass).

Besides reduced voltage, it also causes slow moving depolarization wave and prolonged QRS.

Three basic principles underlie the functions of the circulatory system.

Blood flow to each tissue is almost always precisely controlled according to the needs of the tissue. Tissues need increased supply of nutrients and thus more blood flow when active than when at rest (as much as 20 to 30 times). The microvessels of each tissue continuously monitor tissue needs (eg., availability of oxygen and other nutrients and accumulation of carbon dioxide and other tissue waste products), and control local blood flow precisely to that level required for tissue activity. Nervous control and hormones provide additional help in controlling tissue blood flow. Cardiac output is controlled mainly by the sum of all the local tissue blood flows. After blood flows through a tissue, it returns to the heart via the veins. By pumping the blood immediately back into arteries, the heart responds automatically to this increased inflow of blood. The heart thus automatically responds to the demands of the tissues although it often needs help in the form of special nerve signals to make it pump the required quantities of blood flow. Generally, arterial pressure regulation is independent of either local blood flow or cardiac output control. There is an extensive system for controlling the arterial blood pressure in the circulatory system. For example, if the pressure falls significantly below the normal, within seconds a barrage of nervous reflexes elicits a series of circulatory changes to elevate the pressure back toward normal. This include increased force of heart pumping, contraction of the large venous reservoirs (to provide more blood to the heart), and constriction of most of the arterioles in the body (to accumulate more blood in the large arteries to increase the arterial pressure). With more prolonged periods, the kidneys play an additional major role in pressure control by secreting pressure-controlling hormones and by regulating the blood volume.

3. What is the relationship between local blood flow and local oxygen consumption or metabolism?

Blood flow to each tissue usually is regulated at the minimal level that will supply the tissue's requirements-no more, no less. By controlling local blood flow in exact way, tissues almost never suffer from nutritional deficiency and the workload on the heart is kept at a minimum.

1. List four physiologic functions that are under the control of the autonomic nervous system (ANS).

Blood pressure Heart rate and force Degree of arteriolar constriction GI motility and secretion Micturition Body temperature Degree of arteriolar constriction Sweating Secretions of endocrine and exocrine glands

6. What are the standard units of pressure? What do they represent?

Blood pressure is mostly measured/expressed in mm Hg (since initially used by Poiseuolle in 1846). In reality, blood pressure is related to the force exerted by the blood against any unit area of the vessel wall. For example, if the pressure in a vessel is 50 mm Hg, it means that the force exerted is sufficient to push a column of mercury against gravity up to a level 50 mm high. Sometimes, pressure is measured in cm H2O, and accordingly, a pressure of 10 cm H2O means a pressure sufficient to raise a column of water against gravity to a height of 10 cm.

16. State whether the SNS always excites or stimulates effector organs and whether the PNS always inhibits effector organs. State whether SNS and PNS always have opposite effects in effector organs.

Both the SNS and the PNS can have inhibitory or excititory effects on certain organs. Many times, if the parasympathetic fibers excite an organ, the sympathetic fibers will inhibit it but this is NOT always true. Also, it is common that an organ is predominantly controlled by one of the systems over the other

Belongs to a group of substances called kinins, which cause powerful vasodilation. Kinins are small polypeptides that are split away by proteolytic enzymes (kallikrein) from alpha2-globulins in plasma or tissue fluids. Kallikrein is present in the blood and tissue fluids in an inactive form and it is activated by maceration of blood by tissue inflammation, or by other similar chemical or physical effects on the blood or tissues. As the enzyme becomes activated, it acts on alpha2-globulin to release a kinin called kallidin which is then converted by tissue enzymes into bradykinin. Bradykinin, after a few minutes, is inactivated by the enzyme carboxypeptidase or by converting enzyme, the same enzyme that also plays a role in activating angiotensin. A kallikrein inhibitor, which is also present in body fluids, destroys the activated kallikrein enzyme.

Bradykinin: Bradykinin causes powerful arteriolar dilation and capillary permeability. Thus brachial artery injection increases blood flow while a smaller amounts injected locally into tissues can cause marked local edema (due to increased capillary pore size). Thus, kinins may play special roles in regulating blood flow and capillary leakage of fluids in inflamed tissues. Bradykinin may also play a role to help regulate blood flow in the skin, as well as in the salivary and gastrointestinal glands.

Vasodilator Agents

Bradykinin: Histamine:

23. Describe the location and major secretory product of Brunner's glands.

Brunners glands- *** EXAM Q *** - Located in the first 4-5 cm of duodenum- have lots of mucous cells, protects duodenum from acid digestion

an eating disorder characterized by episodes of binge eating followed by vomiting, use of laxatives, etc. Gastric acid dissolves lingual enamel off maxillary cusps and the lingual surfaces of maxillary incisors.

Bulimia nervosa

7. Describe the following three types of disorders which produce hyperthermia and give examples of each type: abnormal hypothalamic function.

C- Hypothalamic function disorders- these are very rare 1- CV accidents (heart attack, etc)- these can change the hypothalamus thermostat - can possibly be treated with barbituates 2- others- a)encephalitis- swelling of the brain b) trauma c) sarcoidosis and granulomatous infections (cause large lymph nodes) ** all of these will reset the hypothalamus at a higher temperature **

sympathetic and parasympathetic innervation of hear

Cardiac sympathetic and parasympathetic nerves. (The vagus nerves to the heart are parasympathetic nerves. Cardiac sympathetic and parasympathetic (called vagus in heart) nerves sympathetic - fight or flight parasympathetic - calming, restorative stimulus

15. What are some of the causes of septic shock? What are some of the special features of septic shock?

Causes: Generalized body infection, peritonitis (from gut, uterus, etc), skin infection, use of unsterilized surgical conditions. • Septic shock can be caused by different bacterial infection. • It causes patient death in modern hospital more than any other kind of shock besides cardiogenic shock. • Can be easily treated with antibiotics and maintaining fluid homeostasis before it becomes irreversible.

12. State the organs/structures that are innervated by cholinergic fibers in the SNS.

Cholinergic fibers in the SNS- there are not very many of these. Most fibers release NE. - The SNS fibers that are cholinergic innervate the sweat glands, erector pili muscles, and a few blood vessels

4. What level of arterial pressure is considered hypertensive?

Chronic hypertension (high blood pressure) is mean arterial pressure greater than the upper range of the accepted normal value (see report of the 7th NJC for current and detail definition). A mean arterial pressure > 110 mm Hg (normal ~ 90 mm Hg) is considered hypertensive. (diastolic blood pressure is > 90 mm Hg and systolic pressure is > 135 mm Hg). There are severe conditions above these measures. Elevation of arterial pressure, even moderately, leads to shortened life expectancy. Severely high pressures (mean arterial pressures =/> 50 % above normal) costs a person to live no more than a few more years. The main causes giving rise to the lethal effects of hypertension include (1) excess workload on the heart (leading to heart failure/heart attack), (2) high 10 pressure-induced damage to major blood vessel in brain (death of major brain portions/cerebral infarct/"stroke"), and (3) high pressure-induced injury in kidneys (renal destruction, kidney failure, uremia, and death).

12. State the effect of codeine on the motility of the GI tract.

Codeine causes hyperpolarization of smooth muscle. (This means that the resting potential is even further away from threshold level. In other words, it needs a much stronger stimulation before it will fire!) Result= decreased motility (constipation

12. State the effect of codeine on the motility of the GI tract.

Codeine causes hyperpolarization of smooth muscle. (This means that the resting potential is even further away from threshold level. In other words, it needs a much stronger stimulation before it will fire!) Result= decreased motility (constipation)

typical organization of the cord gray matter in a single cord segment.

Connections of peripheral sensory fibers and corticospinal fibers with the interneurons and anterior motor neurons of the spinal cord

cardiac output and arterial pressure

Constancy of cardiac output up to a pressure level of 160 mm Hg. Only when the arterial pressure rises above this normal limit does the increasing pressure load cause the cardiac output to fall significantly.

Define constipation. List its major causes and effects.

Constipation = slow movement of feces through large intestine. - Causes: pathologies (tumors, ulcers or adhesions), laxative overuse, spasms of colon, irregular bowel habits - effect = accumulation of feces. If it gets bad enough, the colon can distend to 3-4 inches in diameter. This is megacolon, or Hirschprung's disease...

Define constipation. List its major causes and effects.

Constipation = slow movement of feces through large intestine. - Causes: pathologies (tumors, ulcers or adhesions), laxative overuse, spasms of colon, irregular bowel habits - effect = accumulation of feces. If it gets bad enough, the colon can distend to 3-4 inches in diameter. This is megacolon, or Hirschprung's disease...

Optic disc (blind spot):

Contains no photoreceptors (no rods and cones); optic nerve and blood vessels located here

Ciliary muscle:

Controls the shape of the lens via the suspensory ligaments

Effect on the cardiac output curve of different degrees of sympa- thetic or parasympathetic stimulation.

Curves show relationship between right atrial pressure at the input of the heart and cardiac output (CO, ↑rate and force) into aorta (also similar to the ventricular function curve above).

mechanism of insulin shock vs. diabetic coma

Diabetic coma = too little endogenous insulin, too much blood glucose, exceeds renal Tm, spill glucose and water in urine, lose water, salt, blood pressure, dehydration, ketoacidosis (from beta oxidation of fats), metabolic acidosis, depression of NS, unconsciousness. Takes days to develop, never seen in dental office. Medical emergency, hospitalization. Insulin shock = Too much exogenous insulin was given for the amount of food consumed. Take insulin injection, don't eat, blood glucose falls to levels too low to maintain consciousness. Can occur in minutes; does occur in dental office.

Define diarrhea. List its major causes and effects.

Diarrhea: rapid movement of feces through large intestine ​- Causes: 1) enteritis- infection of intestinal tract, irritates mucosa = ​ secretions 2) psycogenic- nervous tension ® stimulates PNS ® excites motility and secretion of mucous 3) ulcerated colitis- walls of colon are inflamed and ulcerated...

neuromuscular junction from a large, myelinated nerve fiber to a skeletal muscle fiber.

Different views of the motor end plate. A, Longitudinal section through the end plate. B, Surface view of the end plate. C, Electron micrographic appearance of the contact point between a single axon terminal and the muscle fiber membrane. -The nerve fiber forms a complex of branching nerve terminals that invaginate into the surface of the muscle fiber but lie outside the muscle fiber plasma membrane. The entire structure is called the motor end plate. It is covered by one or more Schwann cells that insulate it from the surrounding fluids.

fat digestion - emulsification

Digestion of fats: triglycerides = 3 fatty acids on a glycerol backbone - a very small amount of triglycerides are broken down by lingual lipases, secreted by the lingual salivary glands. - Enzymes that break down triglycerides= lipases. Lipases in the small intestine (secreted by the pancreas) can only attack a fat globule on its outer surface. -since triglycerides are hydrophobic, they tend to form large globules (oil and water don't mix) So, our bodies use bile salts to "emulsify" the fat. The fat molecules are mixed with bile salts, which have both hydrophobic and hydrophilic parts. This allows the fat globules to be broken up into much smaller globules and spread out. This gives lipase a chance to work better!! (The result of emulsification is a micelle- collection of fatty acids surrounded by bile acids)

myosin cross-bridge hinges

Each crossbridge is flexible at two points called hinges—one where the arm leaves the body of the myosin filament, and the other where the head attaches to the arm. The hinged arms allow the heads either to be extended far outward from the body of the myosin filament or to be brought close to the body. The hinged heads in turn participate in the actual contraction process, as discussed in the follow- ing sections.

22. Describe the factors responsible for the emptying of the gallbladder.

Emptying of gallbladder: -CCK!!!!! *** EXAM Q *** Causes contraction of gallbladder and relaxes sphincter of Oddi, forcing contents into duodenum -vagal stimulation (Ach)- promotes motility in other parts of the GI also

End plate potentials (mV) and effects of drugs

End plate potentials (in millivolts). (A) Weakened end plate potential recorded in a curarized muscle, too weak to elicit an action potential. (B) Normal end plate potential eliciting a muscle action potential. (C) Weakened end plate potential caused by botulinum toxin that decreases end plate release of acetylcholine, again too weak to elicit a muscle action potential.

8. What is the function of endothelial derived relaxing factor (EDRF)?

Endothelium-derived relaxing factor (nitric oxide) dilates blood vessels and increases blood flow - Generally, local control of blood flow is effected mainly by microvessels in tissues. - Effect of shear stress- NO release -Effect of endothelial receptor stimulation (by Ach, etc.) - Effects of adverse conditions on NO release. Endothelin

18. Describe the location and function of the enteric nervous system (intramural plexus).

Enteric nervous system- a set of intrinsic nerves located in the GI tract. -made up of Meissner's and Aurbach's plexus -function= causes the intrinsic activity of the GI tract smooth muscle

"spiciness"

Ethanol and capsaicin activate TRPV-1 receptors that are normally activated by hot temperatures - and hence are sensed as hot

definition of cardiac cycle

Event from beginning of one heartbeat to the beginning of the next

Events of the cardiac cycle for left ventricular function, showing changes in left atrial pressure, left ventricular pressure, aortic pressure, ventricular volume, the electrocardiogram, and the phonocardiogram.

Events of the cardiac cycle for left ventricular function, showing changes in left atrial pressure, left ventricular pressure, aortic pressure, ventricular volume, the electrocardiogram, and the phonocardiogram. Six curves shown: • Electrocardiogram with P, Q, R, S, and T waves: - These are electrical voltages generated by the heart and recorded from the surface of the body (see below for detail). • Phenocardiogram: - Recording of sounds produced by heart as it pumps- mainly by heart valve closure.

9. Given the appropriate information, use the indicator-dilution principle to calculate the volumes of the major body fluid compartments.

Ex. 50 kg person -given 1,000,000 counts per minute = Q of RISA -concentration was 417/1.0mL = C V=Q/C = 2398mL for plasma volume = 2.4 liters of 50 kg = 4.8%...

what are some Factors causing Na ions to diffuse inward sufficiently enough to set off automatic regenerative opening of the channels

Examples: mechanical pressure, neurotransmitters, electrical current.

The T tubule action potentials cause release of calcium ions inside the muscle fiber in the immediate vicinity of the myofibrils, and these calcium ions then cause contraction. This overall process is called

Excitation-contraction coupling in the muscle, showing (1) an action potential that causes release of calcium ions from the sarcoplasmic reticulum and then (2) re-uptake of the calcium ions by a calcium pump

basic mechanisms of active transport and secretion of fluid across a layer of cells

Exocrine glands (epithelial cells) create secretions by actively transporting sodium into a restricted space; this osmotically draws water into the space that connects to a duct to the body surface

5. State the major anions and cations in the ECF and ICF. State their normal concentrations.

Extra Cellular Na = 142 K = 4 Ca = 2.4 PO4 = 5 Proteins = 2 Intracellular Na = 10 K = 140 Cl = 4 PO4 = 75 MG = 58 HCO3 = 10 Proteins = 16

30. List the factors that can increase GI blood flow during digestion and absorption.

Factors that increase blood flow in the GI during digestion and absorption- (not discussed in class) -Vasodilators cause increased blood flow in the GI. These include: CCK, vasoactive intestinal peptide, gastrin, secretin, kinins (bradykinin and kallidin) and decreased O2 concentration, which releases adenosine ...

what is the predominate ion that flows throw the acetylcholine channel and why?

Far more sodium ions flow through the acetylcholine channels than any other ions, because... -First, there are only two positive ions in large concentration: sodium ions in the extracellular fluid, and potassium ions in the intracellular fluid. -Second, the very negative potential on the inside of the muscle membrane, -80 to -90 millivolts, pulls the positively charged sodium ions to the inside of the fiber, while simultaneously preventing efflux of the positively charged potassium ions when they attempt to pass outward.

Hyperopia and how its corrected

Farsightedness: Light rays focus behind the retina. -corrected with biconvex lenses, which causes light rays to converge slightly before striking the eye.

(1) Large fibers for great strength of contraction. (2) Extensive sarcoplasmic reticulum for rapid release of calcium ions to initiate contraction. (3) Large amounts of glycolytic enzymes for rapid release of energy by the glycolytic process. (4) Less extensive blood supply because oxidative metabolism is of secondary importance. (5) fewer mitochondria, also because oxidative metabolism is secondary

Fast Fibers. (type II, white) larger, with greater strength of contraction, extensive SR, glycolytic (fast) energy source, fewer mitochondria, etc.

what generates the greatest amount of energy?

Fat

the greater the amount of work performed by the muscle, the greater the amount of ATP that is cleaved, which is called the

Fenn effect

2. How much time is required for the kidneys to respond to an increase in blood pressure? How long to excrete several hundred ml of urine?

Figure 19-11 illustrates the effect of hemorrhage on arterial pressure under two conditions: with and without the RAS functioning. It is demonstrated that the RAS is powerful enough to return the arterial pressure at least halfway back to normal within a few minutes after severe hemorrhage. Therefore, the system sometimes can be lifesaving, particularly in circulatory shock. The system is, however, slow for blood pressure control compared to nervous reflexes or the sympathetic NE/EP mechanism.

Very strong excitatory signals can produce premature contractions

Force of ventricular heart muscle contraction, showing also duration of the refractory period and relative refractory period, plus the effect of premature contraction. Note that premature contractions do not cause wave summation, as occurs in skeletal muscle.

3. Describe the major functions served by mucus.

Function of mucosa- coats food and chyme, prevents enzymatic digestion of gastric and intestinal mucosa, buffering agent

Major Functions of Vitamin A and deficiency causes:

Functions -Formation of retinal pigments -Normal growth of epithelial cells Deficiency causes: -scaliness of skin, acne -failure to grow in young, including skeletal growth -atrophy of testicular germinal epithelium -failure of reproductive function -keratinization of the cornea, corneal opacity, blindness

gastrointestinal disorders

Gastritis Peptic Ulcer Sprue Fluoride/Hydrofluoric Acid

functional significance of fast and slow twitch fibers

Generally, fast fibers are adapted for powerful muscle contraction, whereas slow fibers are adapted for prolonged muscle activity.

1. Increased calcium ion concentration in vascular smooth muscle causes vasoconstriction (Chapter 8). 2. Increased potassium ion concentration within the physiological range, causes vasodilation, and this is due to the ability of potassium ions to inhibit smooth muscle contraction. 3. Increased magnesium ion concentration causes powerful vasodilation. 4. Increased hydrogen ion concentration (decrease in pH) causes dilation of the arterioles, but a slight decrease in concentration causes arteriolar constriction. 5. Anions with marked effects on blood vessels are acetate and citrate, both of which cause mild vasodilation. 6. Increased carbon dioxide concentration results in moderate vasodilation in most tissues but marked vasodilation in the brain. Carbon dioxide by acting on brain vasomotor center has a powerful indirect effect mediated through the sympathetic nervous vasoconstrictor system. This causes widespread vasoconstriction.

Generally, most vasodilators or vasoconstrictors have little effect on long-term blood flow unless they alter metabolic rate of the tissues. Tissue blood flow and cardiac output (the sum of flow to all of the body's tissues) are not substantially altered in most cases, except for a day or two, when one chronically infuses large amounts of powerful vasoconstrictors (eg., angiotensin II or bradykinin). Why is blood flow not significantly altered in most tissues even in the presence of very large amounts of these vasoactive agents? Answer: Each tissue has the ability to autoregulate its own blood flow according to the metabolic needs and other functions of the tissue. In other words, a powerful vasoconstrictor, such as angiotensin II, may cause transient decreases in tissue blood flow and cardiac output but usually has little long-term effect unless it alters metabolic rate of the tissues. Similarly, most vasodilators cause only short-term alterations in blood flow and cardiac output unless they change tissue metabolism. Thus, blood flow, in general, is regulated by the specific needs of tissues so long as the arterial pressure is adequately functioning.

Color Blindness:

Genetic absence of blue, green or red cones, or some combination of the three. Among Caucasians, 8% of males and 0.4% of females are color blind. Can be a side effect of Viagra, which inhibits retinal (as well as penile) phosphodiesterase.

Fovea:

Greatest visual acuity; contains only CONE photoreceptors, no rods

11. List 3 types of tissue from which angiogenic factors are released.

Growth factors (mostly small peptides) that increase growth of new blood vessels have been found. Three of these vascular endothelial growth factor (VEGF), fibroblast growth factor, and angiogenin.

***8. State the chemical components of the bicarbonate buffer system.

H2O + CO2 ↔H2CO3 ↔ H+ + HCO3- -Water combines with CO2, and forms carbonic acid (H2CO3). - Bicarbonate then dissociates into H+ and HCO3-

basic chemical process for the digestion of fats, carbohydrates and proteins?

HYDROLYSIS

This bacterium can burrow into and through the mucus and secrete enzymes that liquefy the mucus layer. This allows direct access of acid and enzymes to the gastric epithelium.

Helicobacter pylori

4. Describe the essential features of hemodialysis.

Hemodialysis- how patients with kidney failure stay alive!! - Essential charactaristics: Hemodialysis takes advantage of DIFFUSION to clean a person's blood. The blood is shunted through a semipermeable membrane. ON the outside of the membrane is dialyzing fluid. Substances can diffuse and exchange between the blood and the dialyzing fluid until the optimal solute concentrations are reached - Dialyzing fluid ** Solute concentrations in the dialyzing fluid are not always equal the desired concentration in the blood. They are adjusted so that substances will diffuse in the right direction, and so that the end result is normal plasma concentrations - Interesting Note= If dialysis bath is 1ppm F, F will diffuse into blood (normal plasma conc. is much lower than 1ppm. Result= Extremely high F content in bones. This causes bones to become brittle! -now-days, dialysis centers use reverse-osmosis purified water to make up the dialysis baths, so that there is not excess fluoride in the bath.

hypovulumic shock (hemorrhagic)

Hemorrhagic (hypovolumic) Shock -Hemorrhage is the most common cause of hypovolumic shock, which diminishes blood volume. What are the effects of blood loss? a. dec Blood volume and filling of the circulation (bv) and hence VR and CO b. dec Blood pressure c. Skin changes Pale Gray Cool (hence the name "Cold Shock"

It is released in essentially every tissue of the body upon damage or inflammation or in allergic reaction. The majority histamine is derived from mast cells in damaged tissues and from basophils in the blood. Histamine is a powerful vasodilator of arterioles and (like bradykinin), is capable of increasing capillary permeability, allowing leakage of both fluid and plasma protein into tissues. The intense arteriolar dilation and increased capillary porosity produced by histamine in many pathological conditions cause significant amounts of fluid to leak out of the circulation into the tissues, thus resulting in edema. The local vasodilation and edema caused by of histamine are especially prominent during allergic reactions.

Histamine:

Maintenance of nearly constant conditions in the internal environment (or consistency of physiologic variables).

Homeostasis

14. Distinguish between hunger and appetite.

Hunger= craving for food associate with objective sensations that can e caused by contractions or pain Appetite= similar to hunger, except for an implied desire for specific types of food.

1. List the major cardiovascular diseases.

Hypertension Cardiac Arrhythmias

2. Compare core temperature and peripheral temperature, and describe modes of heat transfer from core to periphery.

III Core Temperature vs. Peripheral Temperature: A- Core temperature= internal structures of the body, very constant- 97-99.5 Normal Fluctuations in temperature: a-diurnal- ~1 degree of difference occurs during the day b-exercise- heavy exercise can increase your core temp to 104 c-mentrual cycle- increases ~1degree during ovulation d-age- example- infants have areas of brown fat, which uncouples oxidative phosphorylation from ATP production, this keeps their core temp. ↑ e/f food- Different types of food require more energy to 'assimilate' it into digestion. Example- out of 100kcal of energy you get from protein, 30kcal of that is used by your body just to assimilate it. Carbs only use 6kcal, and fats 4kcal g.- calorie- 1calorie is the energy required to raise 1gram of water by 1 degree Celcius (1calorie that we see on food packages is actually 1kcalorie, or Calorie) B- Peripheral Temperature- varies due to the outside temperature -peripheral temp= skin and tissues immediately under it * about ½ of your body mass is within 1 inch of the body surface * C- Transfer of heat from core to periphery- Think of it as a car radiator -Heat travels through the blood from the core out to the periphery, where it runs very close to the skin. The skin/shell acts as a radiator, and the outside air cools the blood before it flows back into the core. -Depending on how much the blood needs to be cooled, or needs to conserve heat, the body alters how much blood flows into the periphery- it can vary from ½ to 90 ml/ 100g tissue

21. List the effects of the SNS which increase the ability of the body to deal with stress.

INCREASES arterial pressure blood flow to active muscles metabolism glucose concentration in blood glycolysis in liver and muscle muscle strength mental activity rate of blood coagulation dilation of pupils

8. State how the volumes of ICF and ISF can be determined.

ISF = ECF - Plasma ICF = TBW - ECF (TBW = total body water)

9. What is the function of the venous pump?

If it was not for the valves in the veins, gravitational pressure would cause the venous pressure in the feet to be ~ 90 mm Hg in a standing adult. Every time one moves the legs and tightens the muscles, however, it compresses the veins in or adjacent to the muscles, squeezing the blood out of the veins. the valves in the veins are arranged so that the direction of blood flow can only be toward the heart. Consequently, each time a person moves the legs or tenses the muscles, a certain amount of blood is propelled toward the heart (known as "venous pump" or "muscle pump,"), lowering the pressure in the veins. This keeps the venous pressure in the feet of a walking adult less than 20 mm Hg.

25. Describe the function of the ileocecal valve and sphincter and discuss the controlling factors.

Ileocecal valve - prevents backflow of fecal contents from the colon into the small intestine -Ileocecal sphincter- thickened muscular coat in the few centimeters of ileum before you get to the valve. Normally remains mildly constricted, slows emptying of the ileum, except after a meal. -controlling factors= -chemical irritation in the cecum (beginning of large intestine) keeps sphincter closed, delays emptying. -lots of volume in the cecum (it is stretched) also delays emptying - watery volume in cecum promoted emptying ...

3. Why does the heart remain depolarized during the plateau period?

In cardiac muscle, the action potential is caused by opening of two types of channels: (1) the same fast sodium channels as those in skeletal muscle and (2) another entirely different population of slow calcium channels, which are also called calcium-sodium channels. This second population of channels differs from the fast sodium channels in that they are slower to open and, even more important, remain open for several tenths of a second. During this time, a large quantity of both calcium and sodium ions flows through these channels to the interior of the cardiac muscle fiber, and this maintains a prolonged period of depolarization, causing the plateau in the action potential. Further, the calcium ions that enter during this plateau phase activate the muscle contractile process, while the calcium ions that cause skeletal muscle con- traction are derived from the intracellular sarcoplasmic reticulum.

16. Define "alkaline tide" and describe its physiologic basis.

In order to protect stomach mucosa from the acid in the stomach, the surface mucous cells secrete a LOT of highly alkaline, thick mucous.

how do inhibitory substances relax the smooth muscle?

Inhibitory substances either close Ca2+ and Na+ channels or open more K+ channels to hyperpolarize cells (thus relaxing the smooth muscle)

structures in inner ear

Inner Ear: The cochlea is pretty complex- -The cochlea is a system of 3 coiled tubes, which run side by side. -In order going across, the tubes are 1) scala vestibuli, 2) scala media, and 3) scala tympani. These three tubes are separated by membranes. -1 and 2 are separated by Reissner's or vestibular membrane (This membrane is so small, that it doesnt impede sound traveling between 1 and 2. So, as far as sound conduction is concerned, these 2 act as a single compartment - 2 and 3 are separated by BASILAR MEMBRANE!!!! Remember this! This is important!!! ** The BASILAR MEMBRANE is the basis for hearing** -Along the basilar membrane are a TON of basilar fibers. As you move from the oval window down, the fibers get longer and less stiff. These fibers will all resonate at different frequencies. -Lying on top of the basilar fibers is the ORGAN OF CORTI. This has lots of specialized hair cells that sense the vibration of the basilar membrane fibers, are bent in different directions depending on the vibration. -Bending the hair cells in one direction causes them to be depolarized, and in the other direction is hyperpolarized. These electrical signals are transmitted to the nerves that are synapsing at the base of the hair cells.

structures in inner ear

Inner Ear: The cochlea is pretty complex- -The cochlea is a system of 3 coiled tubes, which run side by side. -In order going across, the tubes are 1) scala vestibuli, 2) scala media, and 3) scala tympani. These three tubes are separated by membranes. -1 and 2 are separated by Reissner's or vestibular membrane (This membrane is so small, that it doesnt impede sound traveling between 1 and 2. So, as far as sound conduction is concerned, these 2 act as a single compartment - 2 and 3 are separated by BASILAR MEMBRANE!!!! Remember this! This is important!!! ** The BASILAR MEMBRANE is the basis for hearing** -Along the basilar membrane are a TON of basilar fibers. As you move from the oval window down, the fibers get longer and less stiff. These fibers will all resonate at different frequencies. -Lying on top of the basilar fibers is the ORGAN OF CORTI. This has lots of specialized hair cells that sense the vibration of the basilar membrane fibers, are bent in different directions depending on the vibration. -Bending the hair cells in one direction causes them to be depolarized, and in the other direction is hyperpolarized. These electrical signals are transmitted to the nerves that are synapsing at the base of the hair cells.

it takes two types of filaments and what ion to cause contraction

Interaction of One Myosin Filament, Two Actin Filaments, and Calcium Ions to Cause Contraction

The most common test for color blindness

Ishihara Charts

What is the osmolarity of pure water?

It is 0 milliosmol/Kg

Vasopressin

It is also called antidiuretic hormone (ADH); it is even more powerful than angiotensin II as a vasoconstrictor. Vasopressin is formed in nerve cells in the hypothalamus, which is then transported downward by nerve axons to the posterior pituitary gland, where it is finally secreted into the blood. Although the hormone could have enormous effects on circulatory function, only minute amounts of vasopressin are secreted in most cases. Vasopressin has a major function of increasing water reabsorption from the renal tubules back into the blood, helping control body fluid volume. That is why it is also called ADH.

Lens:

Its shape can be varied to focus the image on the retina

colonic bacteria synthesize what vitamins?

K, B12 (cobalamin), B1 (thiamin), B2 (riboflavin)

adverse effects of hydrofluoric acid

Key points: • F- combines with H+ to form the weak acid HF: F- + H+ <-> HF; pK = 3.45. • Stomach pH ranges from 1 to 3. • Swallowed F- is immediately converted to HF in the acidic contents of the stomach. • HF, like water, diffuses easily through the epithelium; F- does not! • In stomach mucosal tissue the pH is ~7 so HF is converted back into F- and H+. • Sufficiently high concentrations of both F- and H+ cause tissue damage.

Know the approximate caloric content of one liter of 5% (isotonic) glucose in water and how much that contributes to the daily energy requirement of an individual.

Know the approximate caloric content of one liter of 5% (isotonic) glucose in water and how much that contributes to the daily energy requirement of an individual.

Know the time required to oxidize 10 kg (22 lbs) of excess body fat.

Know the time required to oxidize 10 kg (22 lbs) of excess body fat.

Coronary ischemia

Lack of sufficient blood flow depresses metabolism in muscle due to ↓ O2 and nutrients and accumulation of CO2. This decreases repolarization membrane in severely ischemic areas. As there is sufficient blood flow for function, muscle may not die and injury potential continue to flow.

7. In what plane do the limb leads (I, II, and III) orient the electrical axis of the heart?

Lead I- right arm and left arm Lead II- right arm and left leg Lead III- left arm and left leg

ventricular stroke work output as a function of left and right mean atrial pressures.

Left and right ventricular function curves recorded from dogs, depicting ventricular stroke work output as a function of left and right mean atrial pressures.

22. State the effect of fatty food on the emptying time of the stomach and list the hormones that may account for this effect.

Lots of fatty foods causes the stomach to empty more slowly, because fats take longer to digest. The presence of fatty foods stimulates cholecystokinin (CCK) to be secreted from the mucosa of the jejunum. This blocks increases stomach motility (more information about this hormone in

4. List the major types of glands that are found in, or are associated with, the alimentary tract and describe the chemical compositions of their secretions.

Major glands 1- salivary glands- see details in BO #6 2- oxytinic glands- in stomach- mucous cells (secrete mucous), peptic/chief cells(secrete large quantities of pepsinogen), and parietal/oxytinic cells (secrete hydrochloric acid and intrinsic factor) 3- pyloric glands- secrete lots of mucous, a small amt. of pepsinogen, and gastrin 4- Brunner's glands- See BO #2 5- Crypts of Liberkuhn- infoldings of GI mucosa that contain goblet cells (mucous) and enterocyes (water, electrolytes, and enzymes

29. List the major organs whose venous blood flows through the portal vein.

Major organs whose venous blood flows through the portal vein= Splanchnic circulation - Splanchnic circulation is a system that takes all of the venous blood flowing out of the gut, spleen, and pancreas and directs it through the portal vein, into the liver. Once in the liver, the blood passes through millions of fine liver sinusoids, and leaves via hepatic veins, which empty straight into the vena cava.

6. Name the major salivary glands, the major characteristics (serous or mucous) of their secretions and the normal range for daily salivary flow.

Major salivary glands -Parotid- serous secretion- -Submandibular and Sublingual- mix of serous and mucous -Daily salivary flow = 1L

List the major sources of gases in the GI tract and the major types of gas found in the stomach and in the large intestine. State the average daily quantity of gas entering or formed in, and then expelled from, the large intestine. State what happens to the remainder.

Major sources of gas: swallowed air, gas as a result of bacterial action, gas that diffuses from the blood into the GI Types of gas: Stomach: N2 and O2, Sm. Intestine CO2 (from HCl and bicarbonate reaction), Large intestine- CH4 (methane) CO2 and H2 Per day ~ 7-10L of gas is made/arrives in large intestine, but only 0.6 L leave through the anus... the rest is reabsorbed into the intestinal mucosa

List the major sources of gases in the GI tract and the major types of gas found in the stomach and in the large intestine. State the average daily quantity of gas entering or formed in, and then expelled from, the large intestine. State what happens to the remainder.

Major sources of gas: swallowed air, gas as a result of bacterial action, gas that diffuses from the blood into the GI Types of gas: Stomach: N2 and O2, Sm. Intestine CO2 (from HCl and bicarbonate reaction), Larg intestine- CH4 (methane) CO2 and H2 Per day ~ 7-10L of gas is made/arrives in large intestine, but only 0.6 L leave through the anus... the rest is reabsorbed into the intestinal mucosa

15. Define "mastication" and "deglutition".

Mastication= chewing Deglutition= swallowing

16. What is cardiac reserve?

Maximum % that the CO can increase above normal= cardiac reserve (CR) • Values for normal young adult= 300-400%, for athletically trained person= 500-600%; no cardiac reserve for heart failure. Any factor that prevents the heart from pumping satisfactorily decreases CR. • Examples: ischemic heart disease, vitamin deficiency, etc. (see figure)

when can maximum efficiency be realized?

Maximum efficiency can be realized only when the muscle contracts at a moderate velocity. If the muscle contracts slowly or without any movement, small amounts of maintenance heat are released during con- traction, even though little or no work is performed, thereby decreasing the conversion efficiency to as little as zero. Conversely, if contraction is too rapid, large pro- portions of the energy are used to overcome viscous friction within the muscle itself, and this, too, reduces the efficiency of contraction. Ordinarily, maximum efficiency is developed when the velocity of contraction is about 30 per cent of maximum.

region of maximum visual acuity. Is it due to rods or cones? Is it central or peripheral?

Maximum visual acuity = FOVEA This is CENTRAL, and is due to CONES

CIRCULATORY SHOCK

Means generalized inadequacy of blood flow throughout the body to the extent that the body tissues are damaged due to too little flow, especially too little delivery of O2 and other nutrients.

structures in middle ear

Middle Ear: -The beginning of the middle ear is the tympanic membrane. The ossicles (malleus, incus, and stapes) are attached in a row behind the membrane. The malleus is attached to the tympanic membrane. The malleus is bound to the incus by ligaments, so whenever the malleus moves, the incus moves with it. The stapes articulates with the incus, and also sits at the opening of the inner ear (the oval window) -sound waves pass through the ossicles in the middle ear, and are conducted through the oval window, into the cochlea

Strabismus:

Misalignment of the eyes. Also called "wandering eye" or "crossed-eyes." Due to visual images not falling on corresponding retinal points of the two eyes.

anatomy of heart valve

Mitral and aortic valves (the left ventricular valves) -note presence of papillary muscle

most frequent sites where peptic ulcers form, the major causes the ulcerations and the various treatments of these lesions.

Most common site for peptic ulcer to form= first few centimeters of the duodenum -pyloric peptic ulcer -cardia peptic ulcer -marginal peptic ulcer

gastric gland showing the major types of cells:

Mucous cells (mucus) Parietal cells (HCl, intrinsic factor) Endocrine cells (pepsinogen) Chief cells (gastrin)

gastric gland showing the major types of cells:

Mucous cells (mucus) Parietal cells (HCl, intrinsic factor) Endocrine cells (pepsinogen) Chief cells (gastrin)

what type of smooth muscle can be depolarized without an action potential

Multi-Unit Smooth Muscle

This type of smooth muscle is composed of discrete, separate smooth muscle fibers. Each fiber operates independently of the others and often is innervated by a single nerve ending, as occurs for skeletal muscle fibers.

Multi-Unit Smooth Muscle. Further, the outer surfaces of these fibers, like those of skeletal muscle fibers, are covered by a thin layer of basement membrane-like substance, a mixture of fine collagen and glycoprotein that helps insulate the separate fibers from one another.

t/f Normally SKM fibers excited by large myelinated nerve fibers which attach to the muscle fibers at the?

NMJ

5. State which compounds contribute to the increased NPN in renal failure.

NPN=non protein nitrogen - substances that contribute to NPN= urea, creatinine, uric acid !!! (KNOW THESE!!)

why is it usually not possible for the sodium channels to open again without the nerve fiber's first repolarizing.

Na inactivation gate will not reopen until the membrane potential returns to or near the original resting membrane potential level.

Na/ K intracellular/extracellular composition of EC fluids

Na+ - Ex: 142* - In: 10* K+ - Ex: 4* - In: 140* *mEq/L

four transporter proteins key in action potential mechanism

Na+/K+ pump K+/Na+ leak channels voltage gated sodium channels voltage gated potassium channels

What is an electrogenic pump?

Na+/K+ pump is an electrogenic pump -This produces a net outward current that contributes to the internal negativity of the cell.

Summary: sequence of NMJ events that leads to muscle contraction

Nerve AP→ release of Ach → binding of Ach with receptor → activation of receptor → sodium influx into SKM fibers → AP, etc.

how does one test for nerve conduction deafness

Nerve vs. Conduction deafness- -Nerve deafness is when there is actually damage to the auditory nerves or the cochlea. This can also be called 'inner ear' deafness -An audiometer would be used to test air and bone conduction. For air conduction, they hold the sound source up in front of the person's ear, to see if they can hear. For bone conduction, they hold the sound source against a bone, like the mastoid process, to see if the sound travels through the bone and they can hear. -If there is no difference in bone vs. air conduction, then the patient has nerve deafness -Conduction deafness, or 'middle ear' deafness, occurs when the bones of the middle ear (ossicles) cannot transmit sound. This 'fibrosis' of the middle ear can result from repeated ear infections or from otosclerosis. -In this case, the patient would not be able to hear via air conduction, because the ossicles are not working, but when bone conduction is tested, the sound waves can still travel through other bones and reach the cochlea, and the patient demonstrates some hearing

effects of N2O on Cobalamin (Vitamin B12) levels and explain the clinical condition that can result.

Nitrous Oxide irreversibly binds to and oxidizes Vitamin B12, which inhibits it from being absorbed. So, if you are in an environment that uses a lot of N2O (like a dental office), you should take a vitamin supplement that contains B12 -Condition that can result= pernicious anemia. -Neurological symptoms include those of demyelination diseases with loss of peripheral sensation and, in severe cases, paralysis.

In addition, many antihypertensive medications have undesired oral side-effects or conditions that require assessment and potential intervention by dentists. 1 Examples of such drugs include the following:

Nnifedepin with gingival enlargement; prazosin with orthostatic hypotension, clonidine with parotid swelling and xerostmia; hydrochlorothiazide with lichenoid reactions; atenolol with xerostomia; captopril with dysgeusia, etc.

Atrial fibrillation

No P waves from atria or only fine and very low voltage wave record. The waves that can be seen are ventricular QRS and T waves.

NE a powerful vasoconstrictor but EP is less so and in some tissues even causes mild vasodilation. (Eg., dilatation of coronary arteries during increased heart activity).

Norepinephrine (NE) and Epinephrine (EP) Stimulation of sympathetic nerves (eg, during stress, exercise) release NE, which excites the heart and contracts the veins and arterioles. Also, sympathetic nerves to the adrenal medullae cause the glands to secrete both NE (minor) and EP into the blood. These hormones then circulate and cause similar effects on the circulation as direct sympathetic stimulation.

Vasoconstrictor Agents

Norepinephrine (NE) and Epinephrine (EP) Angiotensin II Vasopressin

14. Describe the mechanisms whereby norepinephrine is removed from the neuroeffector site.

Norepinephrine removal- NE is also removed from the synaptic cleft, for the same reasons. There are two mechanisms that can remove NE 1- NE is reabsorbed back into the cell it was released from, where it gets broken down by MAO (monoamine oxidase) or catechol-o-methyltransferase 2- NE can also diffuse away from the synapse - ~50-80% is removed by reuptake, 20-50% removed by diffusion

Progressive Changes in Cardiac Output After Myocardial Infarction: Compensated Heart Failure

Normal CO: Point A: normal operation point (CO= 5L; RA pres:0 mmHg) After Heart damage: CO lowest, but shortly after goes to B with CO= 2L and RA pres= 4 mmHg (↑due to damming of blood); may be associated with short period of fainting. Increased Sym reflex at various at various levels compensates heart activity rapidly, while the Para↓. At this point, new CO and RA pres established at point C. Thus, a person with sudden moderate heart attack experiences only cardiac pain and a few second of fainting, which is then compensated by Sym reflex.

Emmetropia

Normal Vision: Light rays are focused on the retina.

Transverse (T) tubule - sarcoplasmic reticulum system.

Note that the T tubules communicate with the outside of the cell membrane, and deep in the muscle fiber, each T tubule lies adjacent to the ends of longitudinal sarcoplasmic reticulum tubules that surround all sides of the actual myofibrils that contract. This illustration was drawn from frog muscle, which has one T tubule per sarcomere, located at the Z line. A similar arrangement is found in mammalian heart muscle, but mammalian skeletal muscle has two T tubules per sarcomere, located at the A-I band junctions. -Not shown in the figure is the fact that these tubules branch among themselves so that they form entire planes of T tubules interlacing among all the separate myofibrils.

Release of acetylcholine from synaptic vesicles at the neural membrane of the neuromuscular junction.

Note the proximity of the release sites in the neural membrane to the acetylcholine receptors in the muscle membrane, at the mouths of the subneural clefts. -On inside surface of the neural membranes are linear dense bars. To each side of each dense bar are protein particles that penetrate the membrane and are voltage-gated calcium channels. These channels allow the influx of Ca into nerve ending for the release of Ach (called exocytosis).

relation of muscle spindle (intrafusal fibers) to the large extrafusal skeletal fibers

Note: -there is motor AND sensory innervation of the muscle spindle and the large extrafusal muscle fibers -2 types of muscle fibers (intrafusal and extrafusal) are parallel to each other. -Each spindle is built around 3-12 very small intrafusal muscle fibers whose ends are attached to surrounding large extrafusal muscle fibers. -The central part of the intrafusal fibers has either no or few actin and myosin filaments. Thus, this region does not contract when the ends do, but it serves as a sensory receptor.

Organization of the A-V node.

Organization of the A-V node. The numbers represent the interval of time from the origin of the impulse in the sinus node. The values have been extrapolated to human beings. The internodal and interatrial pathways transmit impulses in the atrium. - These pathways subsequently carry impulses to the AV node. • The AV nodes delays impulses from the atria to the ventricles and this allows atria to empty contents into ventricles before ventricular contraction occurs.

10. Describe the role of oxygen in the long-term regulation of tissue vascularity.

Oxygen is also important for long-term control of blood flow (eg., increased vascularity in tissues of animals that live at high altitudes where oxygen is low; vascular growth changes in retina of premature baby's eyes put into oxygen tents or taken out of the oxygen tent- retrolental fibroplasias)

9. List the major secretory products of the oxyntic glands and of the pyloric glands of the stomach.

Oxytinic glands: mucous, pepsinogen, and HCl - Pyloric glands: mucous and gastrin

5. What mechanical event in the cardiac cycle immediately precedes the QRS complex?

P wave is caused by spread of depolarization through the atria, and this is followed by atrial contraction, which causes a slight rise in the atrial pressure curve immediately after the electrocardiographic P wave.

Atrial premature beat

P wave occurs too soon in the heart cycle; P-R interval is shortened indicating that the ectopic origin of the beat is the a

1. What does the P-wave of the electrocardiogram represent?

P wave represents atrial depolarization just prior to or at beginning of atrial contraction

7. Name two compounds which can be used to determine the volumes of: TBW; ECF; and plasma.

PLasma = RISA and Evan's Blue... EXF = inulin, 35SO4 total body water = 3H20 (radioactive H2O)

17. Describe the major effects of the SNS and the PNS on the: . eye;

PNS - constricts pupil - near vision SNS - dilates pupil - far vision

17. Describe the major effects of the SNS and the PNS on the c. heart;

PNS - dec rate/force SNS - inc rate/force

17. Describe the major effects of the SNS and the PNS on the:b. GI system;

PNS - inc. peristalsis and tone - relaxes sphincters SNS - dec. peristalsis and tone - inc. tone of sphinctors

17. Describe the major effects of the SNS and the PNS on the d. systemic blood vessels.

PNS - little or no effect SNS - constricted

4. State which of the chemical buffer systems of the body has the greatest buffering capacity.

PROTEINS have the highest buffering capacity in the body. Proteins are the most plentiful buffers in the body, and regulate the pH INSIDE CELLS

extrinsic vs intrinsic factors in pernicious anamia.

Pernicious anemia - lack of EXTRINSIC, vit. B12/cobalamin, or lack of intrinsic factor OR -lac of INTRINSIC factor- secreted by the stomach (this was covered on the last exam)- protects B12 from being degraded, helps it to be absorbed -Requirement for B12= 3ug/ day

Retina:

Photosensitive layer in the posterior chamber

What is the value for normal plasma osmolarity?

Plasma or blood is ~ 300 mosmoles/kg of water ( to be more exact it is 290 mosm/Kg)

End-diastolic pressure when ventricle has become filled. Preload is affected by venous blood pressure and the rate of venous return. These are affected by venous tone and volume of circulating blood.

Preload

preload and afterload

Preload: End-diastolic pressure when ventricle has become filled. Preload is affected by venous blood pressure and the rate of venous return. These are affected by venous tone and volume of circulating blood. Afterload: The pressure that the ventricle must generate in order to eject blood out of the heart. For the left ventricle afterload is a function of the aortic pressure.

17. Distinguish between primary and secondary peristalsis of the esophagus.

Primary peristalsis of esophagus= continuation of wave that begins in the pharynx during the last phase of swallowing

7. Describe how the sodium, potassium, chloride and bicarbonate concentrations of the "primary" salivary secretion change as the fluid passes through the ductal system.

Primary salivary secretion= not under hormonal control, solute concentrations resemble ECF (except no glucose). Also contains ptyalin (breaks down carbohydrates) and mucous - Once it enters the salivary ducts, aldosterone effects the fluid (by effecting the duct cells the same way it effects the kidneys. -Na concentration ↓ (is actively reabsorbed from the saliva). Goes from 140mM to 40mM (Chloride passively follows Na reabsorption) - Bicarbonate is secreted - Potassium is secreted

Greatly depressed cardiac output (CO) indicating decompensated heart

Progressive fluid retention raises the right atrial pressure over a period of days, and the cardiac output (CO) progresses from point A to point F, until death occurs.

Complete A-V block

Prolonged P-R interval caused by first degree of A-V heart block (affecting bundle of His).

15. Describe the sequence of events leading to acute pulmonary edema in chronic heart failure.

Pulmonary edema begins with an increased filtration through the loose junctions of the pulmonary capillaries. As the intracapillary pressure increases, normally impermeable (tight) junctions between the alveolar cells open, permitting alveolar flooding to occur.

Describe two purposes of contracting the muscle spindle fibers at the same time that the extrafusal fibers contract.

Purpose of coactivation of alpha and gamma motor neurons: • Keeps muscle spindles from opposing willed or voluntary contraction of extrafusal fibers. • Maintains proper damping of muscle regardless of its length. If muscle spindles (gamma activation of intrafusal fibers) do not contract and reflex along with the extrafusal fibers, the sensory element would be limp at one time or overstretched at another. Coactivation ensures that information about muscle length is continuously available to the higher motor centers.

usual range of frequencies that can normally be heard.

Range of frequencies- Children can hear sounds ranging from 30-20,000 cycles/sec. - However, this range is somewhat dependent on the loudness of the sound. The extremes of the frequency range cannot be heard unless the sound is sufficiently loud. (example- at -60dB, the average range is 500-5000 cycles/sec.) - In old age, the frequency range of hearing falls to 50 to 8000 cycles per second or less

usual range of frequencies that can normally be heard.

Range of frequencies- Children can hear sounds ranging from 30-20,000 cycles/sec. - However, this range is somewhat dependent on the loudness of the sound. The extremes of the frequency range cannot be heard unless the sound is sufficiently loud.(example- at -60dB, the average range is 500-5000 cycles/sec.) - In old age, the frequency range of hearing falls to 50 to 8000 cycles per second or less

Special examples of acute 'metabolic' control of local blood flow

Reactive hyperemia: Occurs after blood supply to tissue is blocked for a short time and then unblocked. Usually blood flow to tissue increases 4-6 times. The block causes O2 deficiency, etc. and during hyperemia, there is a 'repay and wash out'. Acute hyperemia:Occurs when tissue metabolic rate increases, causing increased blood flow to sustain increased demand. - Also related is increased accumulation of vasodilator substances. - For example, increased activity skeletal muscle during exercise leads to greater release of vasodilator substances to sustain new level of muscle function.

**21. Describe how the kidneys correct a metabolic acidosis and a metabolic alkalosis.

Renal (kidney) compensation for metabolic disturbances (sort of talked about in class... not very clear) - acidosis- kidney resorbs more bicarbonate - alkalosis- kidney excretes more bicarbonate Additional information: -Ammonia buffer system: more important than phosphate -principle source of ammonia in urine = glutamine -** EXAM Q ** The enzyme that breaks down glutamine and releases ammonia = Glutaminase!!! In chronic acidosis, the activity of this enzyme ↑ !!! -Ammonia buffers in the distal nephron

where do repetitive self-induced discharges occur normally?

Repetitive self-induced discharges occur normally in the heart, in most smooth muscle, and in many of the neurons of the central nervous system. These rhyth- mical discharges cause (1) the rhythmical beat of the heart, (2) rhythmical peristalsis of the intestines, and (3) such neuronal events as the rhythmical control of breathing. (Also, almost all other excitable tissues can discharge repetitively if the threshold for stimulation of the tissue cells is reduced low enough. For instance, even large nerve fibers and skeletal muscle fibers, which normally are highly stable, discharge repetitively when they are placed in a solution that contains the drug veratrine or when the calcium ion concentration falls below a critical value, both of which increase sodium permeability of the membrane.)

7. resistance and PRU

Resistance is the impediment to blood flow in a vessel, and it is calculated from measurements of blood flow and pressure difference between two points in a vessel. For example, if the pressure difference is 1 mm Hg and the flow is 1 ml/sec, the resistance is 1 peripheral resistance unit ( PRU). Rarely, the CGS (centimeters, grams, seconds) unit is also used to express resistance. This unit is dyne sec/cm5 = 1333 x mmHg/ml/sec. Blood flow rate in the entire circulation is equal to the rate of blood pumping by the heart, which is equivalent to the cardiac output. This is approximately 100 ml/sec in an adult person. The pressure difference from the systemic arteries to the systemic veins is ~ 100 mm Hg. Thus, the total peripheral resistance (TPR) (ie., resistance of the entire systemic circulation) is ~ 100/100, or 1 PRU. Under conditions in which all blood vessels in the body become strongly constricted, the TPR can rise to as high as 4 PRU. Alternatively, when the vessels dilate, the resistance can fall to as low as 0.2 PRU. Regarding the pulmonary system, the mean pulmonary arterial pressure is ~ 16 mm Hg and the mean left atrial pressure is ~ 2 mm Hg, creating a net pressure difference of ~ 14 mm Hg. When CO is normal at 100 ml/sec, the total pulmonary vascular resistance at rest is ~ 0.14 PRU (which is ~ 1/7 that in the systemic circulation).

19. Describe the pH, PCO2 and HCO3- concentration changes associated with respiratory acidosis and alkalosis and with metabolic acidosis and alkalosis. List some common causes of these acid-base disturbances and state which is most commonly seen in the clinical setting.

Respiratory Acidosis: CAUSED by an increase in CO2¬ ¬ concentration (not exhaling enough) - effects - HCO3 ↑ - because the law of mass action states that when the concentration of a reactant goes up, the reaction is accelerated in that direction, so because -H2O + CO2 ↔H2CO3 ↔ H+ + HCO3-, more CO2 will push the reaction to the right, and you will get more HCO3. - H+ ↑- because of the law of mass action -pH↓- because there are more H+ ions - in respiratory acidosis, the kidneys are stimulated to excrete less HCO3 Respiratory Alkalosis: CAUSED by DECREASE in CO2 concentration (hyperventilation) -effects - HCO3 ↓- because of law of mass action. (reaction is pushed to the left) - H+ ↓- because of law of mass action - pH↑ - because less H+ ions available Metabolic Acidosis- if the pH disturbance is not CAUSED by CO2 changes, then it is termed "metabolic" -Cause= HCO3 ↓ - effects - pH↓- more H+ available - H+ ↑- caused by decreased filtration of HCO3 in tubules - CO2 ↓- body responds by decreasing CO2 (breath faster) Metabolic Alkalosis- caused by rise in bicarbonate concentration -effects - pH↑- less H+ - H+ ↓- caused by increased filtration of bicarbonate - CO2 ↑- body responds by increasing CO2 (breath slower) Causes of these distresses: Respiratory acidosis and alkalosis- changes in breathing rate:emphysema (acidosis) high altitude (alkalosis) Fear, stress, etc (alkalosis from hyperventilation) Metabolic acidosis: diarrhea, deep vomitting, uremia (increased urea conc.), Diabetes mellitis (accumulate acidic byproducts of fat metabolism), renal tubular acidosis, Drugs (calcium inhibitors) Metabolic alkalosis- alkanizing drugs (antacids), gastric vomiting (releases the acid in the stomach), aldosterone (promotes Na+ reabsorption, counterexchanged with H+- too much H+ is excreted) Most common in clinic ? - he didnt talk about this, but my guess is fear/stress induced alkalosis, and diabetes induced acidosis, just because they are so common.

influence of oxidizing carbohydrates, fats or proteins on the respiratory quotient.

Respiratory quotient = rate of CO2 production/ rate of O2 consumption -normal respiratory quotient = 1 (250cc/min of each) - Certain types of food change that: Carbs: RQ= 1.0 Fats: RQ = 0.71 Protein: RQ= 0.83 1. Immediately after a meal, almost all the food that is metabolized is carbohydrates, so that the respiratory quotient at that time is close to 1.00. 2. About 8 to 10 hours after a meal, available carbohydrates have been used up and the respiratory quotient approaches that for fat metabolism, about 0.70. The reason it is lower than 1.00 is much of the oxygen metabolized with fats combines with the hydrogen molecules in the fat molecules so less CO2 is produced. 3. In untreated diabetes mellitus, little carbohydrate can be used by the body's cells under any conditions because insulin is required for this. Therefore, when diabetes is severe, most of the time the respiratory quotient remains near that for fat metabolism, 0.70.

functional consequences of retinitis pigmentosa.

Retinitis Pigmentosa- areas of the retina degenerate and melanin is deposited in the degenerated areas. (Remember that the normal pigment epithelium the underlies the retina produces melanin- a dark pigment- to keep light from bouncing around in the eye) -Here, the melanin is overproduced, and if the pigment cells encroach on the fovea, this further reduces visual accuity -This is a slow progressing disease, and eventually causes blindness -Dr. Pashley also mentioned that if caught early, laser surgery can help correct this condition and prevent blindness

functional consequences of retinitis pigmentosa.

Retinitis Pigmentosa- areas of the retina degenerate and melanin is deposited in the degenerated areas. (Remember that the normal pigment epithelium the underlies the retina produces melanin- a dark pigment- to keep light from bouncing around in the eye) -Here, the melanin is overproduced, and if the pigment cells encroach on the fovea, this further reduces visual accuity -This is a slow progressing disease, and eventually causes blindness -if caught early, laser surgery can help correct this condition and prevent blindness

effects of too little or too much Vitamin A (retinol)

Retinol is necessary to make retinal pigments in rods and cones. Deficiency can cause blindness, poor quality epithelia leading to infection and other disorders. Excess intake (>3.0 mg/day) during pregnancy can cause birth defects. - reproductive failure -keritanization of the cornea (blindness)

AP of cardiac muscle

Rhythmical action potentials (in millivolts) from a Purkinje fiber and from a ventricular muscle fiber, recorded by means of microelectrodes.

Rhythmical discharge of a sinus nodal Fiber

Rhythmical discharge of a sinus nodal fiber. Also, the sinus nodal action potential is compared with that of a ventricular muscle fiber. Sinus node controls rate of beat of entire heart. - At resting MP there is slow leak of Na into fiber - Between AP, resting MP gradually rises due to the slow Na leak till -40 mV - Then, Na-Ca channels get activated allowing entry of both ions, specially Ca to cause AP - Then, K channels open and K ions escape, returning MP to resting potential.... cycle restarts.

mechanisms for the intestinal absorption of sodium and chloride. Compare these with sodium and chloride reabsorption from the nephron.

SODIUM is absorbed: -by specific protein carriers in co-transport with glucose or amino acids -by counter-transport in exchange for hydrogen. -Na+ is actively reabsorbed into the plasma from the gut. CHLORIDE -passively follows, down its concentration gradient. This is similar to how Na and Cl behave in the kidney

Aqueous humor (in anterior chamber):

Secreted by the ciliary body cells into the anterior chamber and drained into the Canal of Schlemm

14. What events occur during severe (decompensated) heart failure? How is it treated?

Severely damaged heart: cannot be recovered by any compensation • CO cannot rise high enough, no normal renal function, etc. • Fluid continues to be retained, more and more edema develops, and ultimately death. This is called decompensated heart failure, whose main cause is failure of heart to pump sufficient blood to make the kidneys excrete the necessary quantity of fluid.

Forward displacement of the iris causing closed-angle glaucoma.

Shallowing of A.C.:

Sinus bradycardia

Shows slow heart rate, usually fewer than 60 beats/min

6. Describe the oxygen demand theory for local blood flow regulation.

Since smooth muscle requires oxygen to remain contracted, the strength of contraction of the sphincters would increase with an increase in oxygen concentration. With the oxygen concentration in the tissue rising above a certain value, the precapillary and metarteriole sphincters would close until the tissue consumes the excess oxygen. When the excess oxygen is consumed and the oxygen decreases low enough, the sphincters would open once more to resume the cycle. Therefore, based on the available information, either a vasodilator substance theory or an oxygen lack theory, or more likely a combination of the two, could explain acute local blood flow regulation in response to the metabolic needs of the tissues.

Heart Conduction System

Sinus node, and the Purkinje system of the heart, showing also the A-V node, atrial internodal pathways, and ventricular bundle branches. - Sinus node(sinoatrial node): initiates cardiac impulse - Internodal pathway: conducts impulse from sinus node to AV node - AV node: delays impulses from atria to ventricles - AV bundle: conducts impulse from AV node to venrticles - Right and left bundles of Purkinje fibers: conduct impulse to all parts of the ventricles

Describe the effect of a sodium-free diet on the absorption of carbohydrates and amino acids.

Sodium restricted diet - should have no significant effect on absorption of carbs or fat -Sodium is required for glucose transport, but even on a sodium restrictive diet, your requires sodium to live. There is still sodium in the body's tissues for this pump to work. -Fat transport- Na does not seem to play any role in that absorption of fat by GI cells

Describe the effect of a sodium-free diet on the absorption of carbohydrates and amino acids.

Sodium restricted diet - should have no significant effect on absorption of carbs or fat (I'm not definitely sure about this though) -Sodium is required for glucose transport, but even on a sodium restrictive diet, your requires sodium to live. There is still sodium in the body's tissues for this pump to work. -Fat transport- Na does not seem to play any role in that absorption of fat by GI cells

-way of achieving an action potential in a neuron which involves input from multiple presynaptic cells. -the algebraic summation of potentials from different areas of input, usually on the dendrites.

Spatial summation (multi-fiber summation, force summation)

adenosine plays role in control of local blood flow

Special role of adenosine in control of local blood flow, particularly in the heart is well recognized. Release of adenosine is increased with reduced coronary flow, enhanced heart activity, or reduced oxygen supply (ischemia). Adenosine is a potent vasodilator. Adenosine may act similarly in skeletal muscle, etc. Adenosine is an important local vasodilator for controlling local blood flow, particularly in the heart. Its release is increased when coronary blood flow becomes too little, and this causes enough local vasodilation in the heart to return coronary blood flow back to normal. Further, whenever the heart becomes more active than normal and the heart's metabolism increases an extra amount, this causes enhanced utilization of oxygen, ultimately causing increased release of adenosine to elicit vasodilation and increased coronary blood flow to fulfill the nutrient demands of the active heart. The same adenosine mechanism is also believed to control blood flow in skeletal muscle and many other tissues, as well as in the heart. However, it is more likely that a combination of several different vasodilators released by the tissues contributes to blood flow regulation in general.

Dental Treatment Modification Levels

Stage I Hypertension - no modifcationl medical referral Stage II " - selective dental care; medical ref feral Stage III - emergent nonstressful procedures stage iv - emergent nonstressful procedures; immediate medical referral

how does stretching the muscle spindle effect rate of firing? what about shortening?

Stretching the muscle spindles increases the rate of firing, whereas shortening the spindle decreases the rate of firing. (Thus, the spindles can send to the spinal cord either positive signals—that is, increased numbers of impulses to indicate stretch of a muscle—or negative signals—below-normal numbers of impulses to indicate that the muscle is un-stretched.)

Atrial flutter-2:1 and 3:1 atrial to ventricle rhythm

Strong P waves, but QRS-T complex follows atrial P wave only 2-3 beats of atria, etc. (2:1 or 3:1 rhythm)

11. What is neurogenic hypertension? What causes it? Why should the dentist be concerned?

Strong stimulation of the sympathetic nervous system causes acute neurogenic hypertension- for example, with excitement or at times during states of anxiety. This causes peripheral vasoconstriction and hypertension. Acute neurogenic hypertension also occurs when the nerves leading from the baroreceptors are cut or when the tractus solitarius is destroyed in each side of the medulla oblongata (areas where the nerves from the carotid and aortic baroreceptors connect in the brain stem). Loss of the normal inhibitory effect on the vasomotor center (caused by normal baroreceptor nervous signals) allows the vasomotor center to become extremely active and the mean arterial pressure to increase from 100 mm Hg to as high as 160 mm Hg. The pressure returns to nearly normal within about 2 days because the response of the vasomotor center to the absent baroreceptor signal fades away (by central "resetting" of the baroreceptor pressure control mechanism). Thus, the neurogenic hypertension caused by sectioning the baroreceptor nerves is mainly an acute type of hypertension.

structutre of heart

Structure of the heart, and course of blood flow through the heart chambers and heart valves.

korotkoff sounds

Summary of Korotkoff sounds Phase 1: faint clear tapping sounds increase as cuff is deflated Phase 2: murmur or swishing sound Phase 3: crisper with increased intensity Phase 4: abrupt muffling of sound with a soft blowing quality Phase 5: after the last sound heard o long as the cuff inflation pressure is too weak to close the vessel (ie., brachial artery), no sounds are heard with the stethoscope. But, when the cuff pressure is sufficient enough to close the artery during part of the arterial pressure cycle, a sound is heard with each pulsation. These sounds are known as Korotkoff sounds. It is believed that the cause of the Korotkoff sounds is mainly blood jetting through the partially occluded vessel (antecubital artery) and the vibrations of the vessel wall. The jet produces turbulence beyond the cuff, setting up the vibrations heard via the stethoscope. To determine blood pressure, cuff-pressure is elevated above arterial systolic pressure, which collapses the brachial artery and prevents blood jets into the lower artery. No Korotkoff sounds are heard during this time.

adding together of individual twitch contractions to increase the intensity of overall muscle contraction.

Summation

3. Name the two major divisions of the ANS.

Sympathetic Parasymphathetic

t/f An average of 2-3 microliters is formed each minute by the cilliary process

T

initiation of contraction begins with AP in muscle fibers, followed by spread to interior via what structures?

T tubules of SR (transverse tubules)

Sarcoplasmic Reticulum (SR):

Terminal cisternae and longitudinal tubules • Terminal cisternae form junctional "feet" adjacent to the T-tubule membrane • Serves as intracellular storage compartment for Ca2+

name of theory that describes the interaction between the "activated" actin filaments and the myosin cross-bridges; thus, contraction

The "Walk Along" Theory of Contraction (aka "Ratchet" theory) -The figure shows the heads of two cross-bridges attaching to and disengaging from active sites of an actin filament. -It is postulated that when a head attaches to an active site, this attach- ment simultaneously causes profound changes in the intramolecular forces between the head and arm of its cross-bridge. The new alignment of forces causes the head to tilt toward the arm and to drag the actin fila- ment along with it. -This tilt of the head is called the power stroke. Then, immediately after tilting, the head automatically breaks away from the active site, returns to extended position and combines with a new active site farther down along the actin filament. -Thus, the heads of the cross- bridges bend back and forth and step by step walk along the actin filament, pulling the ends of two suc- cessive actin filaments toward the center of the myosin filament.

2. What is the all-or-nothing principle as applied to the heart?

The all-or-none law is the principle that the strength by which a nerve or muscle fiber responds to a stimulus is not dependent on the strength of the stimulus. If the stimulus is any strength above threshold, the nerve or muscle fiber will give a complete response or otherwise no response at all. An induction shock produces a contraction or fails to do so according to its strength; if it does so at all, it produces the greatest contraction that can be produced by any strength of stimulus in the condition of the muscle at the time." This relationship holds only for the unit of tissue; for the heart the unit is the entire auricles or the entire ventricles. the auricles or ventricles behave as a single unit, so that an adequate stimulus normally produces a full contraction of either the auricles or ventricles.

2. Describe the distribution of the sympathetic parasympathetic nerves to various tissues and organs of the cardiovascular system.

The autonomic nervous system plays a major role in the nervous control of the circulation. The sympathetic nervous system is most important for regulating the circulation, while the parasympathetic nervous system contributes more importantly to regulation of heart function. Sympathetic Nervous System: After passing into the sympathetic chain, the sympathetic nerves go the circulation by two routes to: (1) through specific sympathetic nerves that innervate mainly the vasculature of the heart and the viscera, and (2) into peripheral portions of the spinal nerves distributed to the vasculature of the peripheral areas

4. What is the relationship between pressure and flow in vessels? How does one calculate resistance?

The flow can be calculated by the following formula (Ohm's law) : F = ∆P/R (F is blood flow, ΔP is pressure difference (P1 - P2) between 2 ends, and R is resistance). The formula describes that blood flow is directly proportional to the pressure difference but inversely proportional to resistance. (∆P = F x R; R = ∆P/F) Pressure gradient in the pulmonary circulation is lower than that of the systemic circulation, although blood flow is the same in both. Thus, the total pulmonary vascular resistance is significantly lower.

5. What is a laminar blood flow? What is turbulent blood flow?

The flow of blood at a steady rate through a long, smooth blood vessel is known as laminar flow or streamline flow. Each layer of blood remains the same distance from the vessel wall and the central-most portion of the blood stays in the center of the vessel. The velocity of blood flow in the center of the vessel is far greater than that toward the outer edges (Figure 14-6). Turbulent flow is opposite of this. In turbulent flow, blood flows in all directions in the vessel continually mixing within the vessel. Generally, when the flow rate becomes too great, or blood passes by an obstruction in a vessel, makes a sharp turn and/or when it passes over a rough surface, the flow may then become turbulent, or disorderly

Intrinsic regulation: the Frank-Starling mechanism

The greater the volume of blood entering the heart during diastole (end-diastolic volume), the greater the volume of blood ejected during systolic contraction (stroke volume) (ie., within the physiological limits of the heart).

2. State the etiology of pyelonephritis and explain why "pyelo" patients often exhibit a urinary concentrating defect.

The inflammation begins with a urinary tract infection (due to contamination of urethra with E.coli) -infection reaches pelvis of kidney first, becomes inflamed

1. State the fluid compartment which is implied by the term "internal environment of the cells" and state its major physiologic significance.

The interstitial fluid (ISF) is referred to as the the "internal environment". Cellular metabolism represents an intracellular source of water, and urea, the main end product of protein metabolism which diffuse outward through the ISF and into the plasma compartment.

The Renin-Angiotensin System (RAS): Role in Arterial Pressure Control

The kidneys also have another powerful mechanism for controlling pressure: the renin-angiotensin system (RAS). In Figure 19-10 are presented the functional steps by which the RAS helps to regulate arterial pressure. Renin is an enzyme synthesized and stored in an inactive form (prorenin) in the juxtaglomerular cells (JG cells) of the kidneys. When arterial pressure falls, the prorenin splits and renin is released. Most of the renin passes out of the kidneys to the circulation. However, the rest remains in the local fluids of the kidney and initiate intrarenal functions. Renin acts on another plasma protein, angiotensinogen, to release angiotensin I, which is a mild vasoconstrictor (but not enough to cause significant circulatory changes) (Figure 19-10). Two additional amino acids are split from the angiotensin I to form angiotensin II (particularly in the lungs), catalyzed by an enzyme called angiotensin converting enzyme (ACE). Angiotensin II is an extremely powerful vasoconstrictor, but it persists in the blood only for 1 or 2 min since it is rapidly inactivated by multiple blood/tissue enzymes (angiotensinases). Angiotensin II has two principal effects that can elevate arterial pressure: (1) it causes vasoconstriction rapidly (intensely in the arterioles and much less so in the veins), increasing TPR, thereby arterial pressure (Figure 19-10); (2) it increases arterial pressure by decreasing excretion of both salt and water by the kidneys. This slowly increases the EC fluid volume, which then increases arterial pressure in the long-term. This long-term effect, (via EC fluid volume mechanism), is even more powerful than the acute vasoconstrictor mechanism.

Signals from the tendon organ are transmitted both into local areas of the cord and, after synapsing in a dorsal horn of the cord, through long fiber pathways such as the spinocerebellar tracts into the cerebellum and through still other tracts to the cerebral cortex; what is the function of the local cord signal

The local cord signal excites a single inhibitory interneuron that inhibits the anterior motor neuron. This local circuit directly inhibits the individual muscle without affecting adjacent muscles.

maximum strength of contraction

The maximum strength of tetanic contraction of a muscle operating at a normal muscle length averages between 3 and 4 kilograms per square centimeter of muscle, or 50 pounds per square inch.

Heart Murmurs Caused by Valvular Lesions

The murmur of aortic stenosis: • Blood ejected from left ventricle through small scarred opening of aortic valve. • Resistance to ejection increases pressure in the ventricle. • Blood ejected at high velocity through a small opening causes severe turbulence of blood in the root of aorta, and a loud, harsh murmur. The murmur of aortic regurgitation: • Backward blood flow from aorta into left ventricle during diastole causes a "blowing" murmur of high pitch turbulence of blood jet. The murmur of mitral regurgitation: • Blood flows backward through mitral valve into left atrium during systole; sound is similar to above; best heard at apex of heart. Murmur of mitral stenosis: Blood passes with difficulty through stenosed mitral valve from left atrium into left ventricle. Weak and low frequency sounds are heard.

7. Describe the myogenic theory of autoregulation of blood flow.

The myogenic theory is based on the observation that sudden stretch of small blood vessels causes the smooth muscle to contract. Thus, when high arterial pressure stretches the vessel, it causes reactive vascular constriction that reduces blood flow back to normal. At low pressures, however, the stretch of the vessel is less, so that the smooth muscle relaxes, decreasing vascular resistance and normalizing flow. The myogenic response is inherent to vascular smooth muscle, (occurs in the absence of neural or hormonal effects). Myogenic contraction is initiated by stretch-induced vascular depolarization, which then rapidly increases calcium ion influx into the cells, inducing contraction. Alterations in vascular pressure may also open or close other ion channels that influence vascular contraction. The mechanism is likely to involve mechanical effects of pressure on extracellular proteins that are tethered to cytoskeleton elements of the vascular wall or to ion channels. The myogenic mechanism may prevent excessive stretch of blood vessel caused by increased blood pressure (although its role in blood flow regulation is unclear). Metabolic factors appear to be more important than the myogenic mechanism in circumstances where the metabolic demands of the tissues are significantly increased (eg., during vigorous muscle exercise which can dramatically increase skeletal muscle blood flow).

3. Where is the conduction velocity of the wave of depolarization slowest in the heart? Where is it most rapid?

The numbers on the figure represent the intervals of time, in fractions of a second, that lapse between the origin of the cardiac impulse in the sinus node and its appear- ance at each respective point in the heart. Note that the impulse spreads at moderate velocity through the atria but is delayed more than 0.1 second in the A-V nodal region before appearing in the ventricular septal A-V bundle. Once it has entered this bundle, it spreads very rapidly through the Purkinje fibers to the entire endocardial surfaces of the ventricles. Then the impulse once again spreads slightly less rapidly through the ventricular muscle to the epicardial surfaces.

4. What determines the arterial pulse pressure? Where is the pulse pressure greatest? Is it greatest in the aorta, femoral artery or artery in the foot (dorsal pedis) or is it greatest in capillaries?

The pressure at the height of each pulse, ie., the systolic pressure, is normally ~ 120 mm Hg and at the lowest point, ie., the diastolic pressure, it is ~ 80 mm Hg. The difference between the two, ~ 40 mm Hg, and this is called the pulse pressure. The 2 major factors that can affect the pulse pressure are (a) the stroke volume output of the heart and (b) the compliance (total distensibility) of the arterial tree. A less important factor is the ejection from the heart during systole.

Describe the process for "recharging" the cell membrane following depolarization.

The process for "recharging" or repolarizing the cell membrane following depolarization involves the opening of potassium channels and the diffusion of intracellular potassium to the EC fluid.

23. State the frequency of segmental contractions in the proximal and distal ileum and state the significance of the relative rates.

The rate of contraction slows as you go farther distal down the small intestine. This is significant because it encourages analward movement of the food (Law of the gut)

The slow onset of contraction of smooth muscle, as well as its prolonged contraction, is caused by

The slow onset of contraction of smooth muscle, as well as its prolonged contraction, is caused by the slowness of attachment and detachment of the cross-bridges with the actin filaments. In addition, the initiation of contraction in response to calcium ions is much slower than in skeletal muscle.

Threshold for taste

The threshold for stimulation of the sour taste by hydrochloric acid averages 0.0009 moles/liter, pH 3.0; for stimulation of the salty taste by sodium chloride: 0.01 moles/liter; for the sweet taste by sucrose (table sugar): 0.01 moles/liter; and for the bitter taste by quinine: 0.000008 moles/liter. -Note especially how much more sensitive is the bitter taste sense to stimuli than all the others, which would be expected since this sensation provides an important protective function

Smooth muscle does not have the same striated arrangement of actin and myosin filaments as is found in skeletal muscle.

The upper left-hand fiber shows actin filaments radiating from dense bodies. The lower left-hand fiber and the right-hand diagram demonstrate the relation of myosin filaments to actin filaments. -Individual contractile units consist of actin f. radiating from 2 dense bodies, which overlap single myosin f. located midway between the dense bodies.

3. What is the relationship between venous compliance and cardiac output?

There is a new surge of blood in the arteries with each heartbeat. If there were no distensibility of the arterial system, all of the new blood would have to flow via the peripheral vessels almost instantaneously only during cardiac systole, and no flow would occur during diastole. However, the compliance of the arteries reduces the pressure pulsations to almost no pulsations when the blood reaches the capillaries. As a result, blood flow is largely continuous with very little pulsation.

6. What is the usual relationship between arterial pressure and age?

There is a progressive increase in pressure with age demonstrating the effects of aging on the blood pressure control mechanisms. Beyond the age of 60 years, a slight extra increase in systolic pressure usually occurs and this results from decreasing distensibility, or "hardening," of the arteries (often due to atherosclerosis). Ultimately, a higher systolic pressure with considerable increase in pulse pressure results.

12. Describe how the angiogenesis factor acts to increase tissue vascularity.

These cause new vessels to sprout from other small vessels. The initial step is dissolution of the basement membrane of endothelial cells at the point of sprouting, followed by rapid reproduction of new endothelial cells that stream outward via the vessel wall in cords directed toward the source of the angiogenic factor. The cells in the cord continue to divide and form a tube, which then connects with another similar tube to forms a capillary loop through which blood begins to flow. Some of the new vessels eventually grow to be new vessels. This explains the way in which metabolic factors in local tissues can cause growth of new vessels.

12. Identify four venous reservoirs? How is that blood mobilized from them?

These include (a) the spleen, which can sometimes decrease in size to release as much as 100 ml of blood into other areas (reservoir) of the circulation; (b) the liver, the sinuses of which can release several hundred ml of blood into the rest of the circulation; (c) the large abdominal veins, which can contribute as much as 300 ml; and (d) the venous plexus beneath the skin, which can contribute several hundred ml. The heart and the lungs are also considered blood reservoirs, although they are not parts of the systemic venous reservoir system (eg., the heart shrinks during sympathetic activation, contributing up to 100 ml of blood; the lungs contributing to 100 to 200 ml during low values of pulmonary pressure. The contents can then be expelled into the general circulation (raising the hematocrit) with excitation of the sympathetic nervous system and contraction of the spleen and its vessels.

third and fourth heart sound?

Third heart sound: Occasional very weak rumbling sound heard at beginning of the middle third of diastole, possibly due to oscillation of blood back and forth between walls of the ventricles initiated by rushing blood from the atria. - it has low frequency not heard by the ear but can be recorded in phonocardiogram Fourth heart sound: It is atrial heart sound that can only be recorded in phonocardiogram (sometimes). It occurs when the atria contract, causing inrush of blood into the ventricles which initiates vibration.

what alters the normal/inhibited relationship between the troponin-tropomyosin complex and actin

This inhibition is inhibited by calcium, which binds with the troponin complex, uncovering the active sites of actin, allowing interaction with myosin producing a new condition that leads to contraction

what causes the actin filaments to slide inward among the myosin filaments?

This is caused by forces generated by interaction of the cross-bridges from the myosin filaments with the actin filaments. Under resting conditions, these forces are inactive, but when an action potential travels along the muscle fiber, this causes the sarcoplasmic reticulum to release large quantities of calcium ions that rapidly surround the myofibrils. The calcium ions in turn activate the forces between the myosin and actin filaments, and contrac- tion begins. But energy is needed for the contractile process to proceed. This energy comes from high- energy bonds in the ATP molecule, which is degraded to adenosine diphosphate (ADP) to liberate the energy. In the next few sections, we describe what is known about the details of these molecular processes of contraction.

9. Describe the mechanism for long-term local blood flow regulation.

This mechanism subsequently develops (after acute effect) to help adjust blood flow to match precisely the metabolic needs of tissues. - Changes in tissue vascularity contribute to long-term regulation of blood flow. Example: chronically overactive tissues that demand O2 and other nutrients, need more vessels or vascularity. Low O2 or high altitude stimulates this process. - Angiogenesis- growth of new vessels in presence of angiogenic factors. - Many angiogenic factors are small peptides- 3 are of noting, VEGF, FGF, and angiogenin (work by similar mechanisms). Collateral vessels develop when an artery or a vein is blocked. - New vascular channels develop around the blocked vessel (eg., after thrombosis of coronary arteries).

1. Describe the mechanisms by which the kidney can increase or decrease blood pressure independent of renin-angiotensin.

This system acts slowly but powerfully as follows. If blood volume increases with no alterations in capacitance, arterial pressure also increase. The pressure increase causes the kidneys to excrete the excess volume, thereby bringing the pressure back to normal. An increase in arterial pressure in human of only a few mm Hg can double renal output of water as well as salt. The former is called pressure diuresis while the latter pressure natriuresis.

Precordial leads (chest leads): connections of the body with the electrocardiograph for recording chest leads (LA, left arm; RA, right arm)

This technique can detect minute changes. QRS for V1 and V2 are mostly -ve since the electrodes are nearer to the base of the heart, etc.

What is the name of the filamentous protein that keeps the myosin and actin filaments in place?

Titin -The side-by-side relationship between the myosin and actin filaments is difficult to maintain. This is achieved by a large number of filamentous molecules of a protein called titin. -Each titin molecule has a molecular weight of about 3 million, which makes it one of the largest protein molecules in the body. Also, because it is filamentous, it is very springy. These springy titin molecules act as a framework that holds the myosin and actin filaments in place so that the contractile machinery of the sarcomere will work.

5. Distinguish between tonic and rhythmic contractions and define "slow waves."

Tonic contraction- continuous muscle contraction, may increase or decrease intensity, but is always there. Can be caused by: 1 repetitive spike potentials (action potentials). The higher the frequency of potentials, the stonger the contraction 2-hormones or other factors that cause continuous depolarization of smooth muscle 3-continuous entry of calcium into the cell Rhythmic contraction- the smooth muscle in the GI contracts rhythmically, and this is determined by the frequency of slow waves Slow waves- (this WAS discussed in class) rhythmic changes in the resting membrane potential of GI smooth muscle. Caused by the "leakiness" of GI smooth muscle cells

5. Distinguish between tonic and rhythmic contractions and define "slow waves."

Tonic contraction- continuous muscle contraction, may increase or decrease intensity, but is always there. Can be caused by: 1 repetitive spike potentials (action potentials). The higher the frequency of potentials, the stonger the contraction 2-hormones or other factors that cause continuous depolarization of smooth muscle 3-continuous entry of calcium into the cell Rhythmic contraction- the smooth muscle in the GI contracts rhythmically, and this is determined by the frequency of slow waves Slow waves- (this WAS discussed in class) rhythmic changes in the resting membrane potential of GI smooth muscle. Caused by the "leakiness" of GI smooth muscle cells

2. Describe the relationship between a monophasic action potential from ventricular muscle and an electrocardiogram recorded at the surface of the body.

Top: Monophasic AP from a ventricular muscle fiber during normal cardiac function, showing rapid depolarization and then repolarization occurring slowly during the plateau stage but rapidly toward the end. Bottom: Electrocardiogram recorded simultaneously.

what is the surface area of the intestinal mucosa?

Total surface area= 50 x 60 ft.

Cornea:

Tough, transparent layer over the front of the eye

What is cotransport (called secondary active transport by Guyton)? Give examples.

Transport is driven by the energy already stored in the concentration gradient of another molecule (eg., Na+) - indirect use of energy involved.

26. Describe the major types of movement of the colon and discuss their functions and control.

Types of movement in colon (not discussed in class) -Mixing movement (haustration)- large circular constrictions that mix fecal matter -Propulsive movement (mass movement)- modified type of peristalsis- moves fecal matter down the colon -mass movements initiated after meals by gastrocolic and duodenocolic reflexes. Also can be initiated by intense stimulation of the PNS or over stretching of a segment of the colon.

13. Identify the body fluid in which the phosphate buffer system is quantitatively more important than the bicarbonate buffer system.

URINE - Phosphate is very poorly reabsorbed, so it accumulates in the tubules. So it is a good buffer here because of its quantity. - Also, the pKa of the phosphate system is 6.8, which is around the pH of normal tubular fluid. The phosphate system buffers GREAT here because all buffers work best at their pKa!!!!

5. Define the mechanisms associated with the production of fever.

VI- Fever *** It is VERY important to remember that Fever is a NORMAL physiologic response to infection *** A- Pyrogens= factors that cause fever a) exogenous pyrogens- endotoxins from bacteria, viruses, and fungi b) endogenous pyrogens- substances secreted by monocytes, granulocytes, and Liver kupfer cells (IL-1) which produce prostaglandins c) Prostaglandins- effect hypothalamus- reset thermostat too high B- Characteristics- Pyrogens act on the hypothalamic thermostat- they tell the body to keep its core temperature higher than normal Charactaristics of Fever- - Chills and shivering -The body's thermostat is set too high. The body realized that there is a difference between the set point and the current temperature, so it attempts to raise the body's temperature (shivering increases muscle activity) -Fever "breaking" When the set point returns to normal, suddenly he body realizes that it is too hot and attempts to bring the temp. back to normal through lots of sweat C- Role of fever in protection: some organisms (bacteria) die at this new higher core temperature, also, at a higher temperature, the activity levels of some important enzymes increase

7. Describe the following three types of disorders which produce hyperthermia and give examples of each type: excessive heat production

VIII - Hyperthermia! ** He really stressed this stuff ** A- Excess heat production 1- exertional hyperthermia- too much exercise effects- dilation of blood vessels- cools the periphery, but not the core - exhaustion, sweat, ↑pulse, ↓ blood pressure, dyspynia (air hunger- gasping?) 2- exertional heat stroke (has nothing to do with CV stroke) -there is a breakdown in temp. regulation, rapid increase in core temperature (can get up to 110), metabolic rate increases -usually due to athletes who work beyond their training (trying to do more than they can) 3- Anesthesia- VERY rare!! trigger= halogenated anesthesia agents symptoms= ↑release of Ca, ↑ muscle contraction, ↑ heart rate, ↑ lactic acid (acidosis) treatment- IV muscle relaxant 4- heat cramps- contraction of muscles, intense cramps after exercise- mainly due to salt loss 5- Others a)thyrotox= endocrine disorder b)pheochro.= adrenal tumor, ↑ NE production, hyper metabolism c)salicylate= similar to brown fat- uncouples ox.phos. and ATP production d)drug abuse= cocaine and amphetamines ↑heat production e)delerium tremors= psychosis, withdrawal from alcohol f) status epilepticus= epileptic seziures

6. Define and write the formula for volume of distribution.

Vd = Q/C Q=quantity added C = concentration -if excreted: Vd = Q-E/C

6. Describe how volume loading (or loss of renal functional mass) can cause hypertension.

Volume-loading hypertension refers to hypertension caused by excess accumulation of extracellular fluid in the body. In experimental animals with kidney mass reduced to ~30% surgically, an increase in salt and water intake causes marked hypertension. The decrease in the kidney mass reduces the kidney's ability to excrete a large load of salt and water efficiently. With salt and water intake reduction, the following events occur (Figure 10-9): - Expanded EC fluid volume and blood volume. - Increased blood volume enhances the circulatory filling pressure, venous return and cardiac output (CO). - Increased CO raises arterial pressure During the first day after increased salt and water intake, there is a decrease in TPR, caused mainly by the baroreceptor reflex mechanism, which attempts to prevent the rise in pressure. After several days, there is a gradual return of CO towards normal due to long-term blood flow autoregulation, which simultaneously causes a secondary increase in TPR. examples 1. Volume-loading hypertension in patients who have no kidneys but are being maintained on an artificial kidney. 2. Hypertension caused by primary aldosteronism (excess secretion of aldosterone).

2. How do the volume-pressure curves of the arterial and venous circulations differ?

Volume-pressure curve expresses the relation of pressure to volume in a vessel or in any portion of the circulation The Figure also illustrated the effects of exciting or inhibiting the vascular sympathetic nerves on the volume-pressure curves in the circulatory system. In the entire systemic venous system, the volume normally ranges from 2000 to 3500 ml, and a change of several hundred ml is required to change the venous pressure only 3 to 5 mm Hg. This is why as much as 0.5 l of blood can be transfused in only a few minutes without significantly altering circulatory function.

Define vomiting. Describe its physiologic basis.

Vomiting- when any part of upper GI tract is irritated or distended, the upper GI rids itstelf of its contents. stimulation by vagus and SNS go to the "vomiting center" ​Physiological basis- ​ ​-Early stages- antiperistalsis moves food upward -Vomiting act- a deep breath, raising of the hyoid bone and larynx (opens upper esophageal sphincter), closing glottis, and lifting the soft palate to close the posterior nares ​ ​(This is like the reverse of the swallowing mechanis...

process for the GI absorption of water and the role of solute transport in this process. Compare this with water reabsorption from the nephron.

Water transport = completely by diffusion through the intestinal membrane. - the osmolarity of chyme can dictate which direction water diffuses (hyperosmotic chyme will cause diffusion of water from the plasma into the chyme - also, as solutes and nutrients are absorbed into the gut, so is an isosmotic equivalent of water

Venous Return Curve: Venous blood flow to heart from systemic circulation at different levels of arterial

When atrial pressure increases, backward force on veins of the systemic circulation decreases VR of blood to heart. If all reflexes are prevented, VR decreases to 0 at atrial pressure of +7 mm Hg. This causes venous stasis and heart pumping also approaches 0 due to decease in VR. Both arterial and venous pressure come to equilibrium when flow in systemic circulation ceases. This is called mean systemic filling pressure.

describe the static response of the spindle receptor (ie., responding to change in length).

When receptor portion is stretched slowly, impulses transmitted from both 1 and 2 endings increase proportionally to the degree of stretch, and transmission continues for many minutes.

the lengthening reaction is enabled by the golgi tendon organ; what is?

When tension on the muscle and, therefore, on the tendon becomes extreme, the inhibitory effect from the tendon organ can be so great that it leads to a sudden reaction in the spinal cord that causes instan- taneous relaxation of the entire muscle. This effect is called the lengthening reaction; it is probably a pro- tective mechanism to prevent tearing of the muscle or avulsion of the tendon from its attachments to the bone.

Inhibitory Nature of the Tendon Reflex and Its Importance

When the Golgi tendon organs of a muscle tendon are stimulated by increased tension in the connecting muscle, signals are transmitted to the spinal cord to cause reflex effects in the respective muscle. This reflex is entirely inhibitory. Thus, this reflex provides a nega- tive feedback mechanism that prevents the develop- ment of too much tension on the muscle.

multiple fiber summation

When the central nervous system sends a weak signal to contract a muscle, the smaller motor units of the muscle may be stimulated in preference to the larger motor units. Then, as the strength of the signal increases, larger and larger motor units begin to be excited as well, with the largest motor units often having as much as 50 times the contractile force of the smallest units. This is called the size principle. It is important, because it allows the gradations of muscle force during weak contraction to occur in small steps, whereas the steps become progressively greater when large amounts of force are required.

Two conditions in which the skeletal nerves and muscles play roles in circulatory responses are considered.

With baroreceptor or chemoreceptor reflex, nerve signals are sent to skeletal muscles, particularly to the abdominal muscles. The venous reservoirs of the abdomen are thus compressed, helping to move blood out of the abdominal vascular 6 reservoirs toward the heart, resulting in availability of increased quantities of blood for the heart to pump (called abdominal compression reflex). The overall effect on the circulation is similar to sympathetic vasoconstrictor responses. Demonstrating the significance of this reflex process, people with paralysis of skeletal muscles have been found to be considerably more prone to hypotensive episodes. Blood vessels are compressed when the skeletal muscles contract during exercise. Expectation of exercise also tightens the muscles, compressing the vessels in the muscles and abdomen. The mobilization of blood from the peripheral vessels into the heart increases cardiac output (CO). The increased in cardiac output then increases the arterial pressure during exercise.

What is Starling's Law of the heart for the Frank-Starling (FS) relationship?

Within physiologic limits, the heart pumps all of the blood that comes to it without allowing excessive damming of blood in the veins.

13. State whether a functioning myenteric plexus is involved in peristalsis.

YES!! In order for peristalsis to occur, you absolutely NEED the myenteric plexus to be functioning!!

a sudden increase in nerve membrane potential of more than 20 to 30 millivolts is normally sufficient to initiate more and more sodium channel opening, thus initiating an action potential at the muscle fiber membrane; what is the change in the electrical potential inside the fiber at the local area of the end plate at the sudden insurgence of calcium ions (end plate potential)? Is it enough to initiate an action potential at the muscle fiber membrane?

Yes, the electrical potential inside the fiber at the local area of the end plate to increase in the positive direction as much as 50 to 75 millivolts,

9. What is the relationship between blood viscosity and hematocrit? What is a normal value for hematocrit?

^ematocrits in a healthy (normal) person and in patients with anemia and polycythemia. The value for adult men ~ 42, while it is ~ 38 for women. These values vary widely, depending on various factors. Effect of hematocrit on blood viscosity is illustrated in Figure 14-11 (Water viscosity = 1). It is clear that the viscosity of blood increases as the hematocrit increases, and viscosity of whole blood at normal hematocrit is ~ 3. This implies that three times as much pressure is needed to force blood as to force water through blood vessel. Tremendous increase in hematocrit as it occurs in polycythemia, can markedly retard blood flow. Other factors can also affect blood viscosity, including plasma protein concentrations, but these effects are so much less (mostly insignificant) than the effect of hematocrit. The viscosity of blood plasma is ~ one-and-a half times that of water.

Ghrelin

a peptide hormone released by the stomach mucosa, enters the blood stream, stimulates secretion by AGRP/NPY neurons in the arcuate nucleus that act on the ventrolateral hypothalamic feeding center to stimulate hunger. After feeding, ghrelin levels in blood fall to low levels.

28. Define or describe each of the following:a. sacral plexus h. b. chewing reflex i. c. gastroenteric reflex j. d. gastrocolic reflex k. e. secretin l. f. gastroileal reflex m. g. gastrin; haustrations mass movements duodenocolic reflex defecation reflex gap junction functional syncytium n. peristaltic rush o. peristaltic reflex p. central lacteal q. teniae coli

a) sacral plexus- origin of PNS pelvic nerves to the distal half of the large intestine and rectum b) chewing reflex- how chewing occurs: when food is placed in the mouth, masticatory muscle contraction is inhibited and the jaw drops, stretching of the jaw excites the stretch reflex to contract the jaw. c) gastroenteric reflex- see BO #24 d) gastrocolic reflex- signal caused by stretching of stomach- signals defecation e) secretin- secreted by S cells in mucosa of duodenum in response to acidic gastric juice from the stomach, inhibits GI motility (see more in Ch 64) f) gastroileal reflex- intensifies peristalsis in the ileum when a peristaltic wave caused by the gastroenteric reflex reaches the ileum g) gastrin- vasodilator, released from small intestine to increase GI motility h) haustrations- see BO #26 i) mass movements- see BO #26 j) duodenocolic reflex- from stretching of duodenum which signals defecation k) defecation reflex- see BO #27 l) gap junction- intercellular junction (as in smooth muscles) that allow low-restistance movement of ions from one cell to another m) functional syncytium- when many muscle fibers are connected in such a way that they act as one unit. This happens with the heart, as well as the smooth muscle in the GI n) peristaltic rush- powerfully peristaltic contractions of the small intestine caused by intense irritation of the intestinal mucosa (such as from infectious diarrhea) o) peristaltic reflex- or myenteric reflex, where a distended segment of the small intestine will initiate peristalsis and slight relaxation of the intestinal segments towards the anus. p) central lacteal- lymphatic vessel in each intestinal villus that take fat absorbed by the intestinal epithelium and place it into lymphatic circulation q) teniae coli- longitudinal muscle of the colon, arranged into three strips, which are important in defecation.

18. List the major stimuli that promote the secretion of: a. secretin; b. CCK.

a) secretin- stimulated by HCl (and some fat) b) CCK- fat and polypeptides

18. List the three major motor functions of the stomach and define chyme.

a) storage of food until it can be processed in the duodenum b) mixing of stored food with gastric secretions c) emptying the food from the stomach into the small intestine at the right rate- so that proper absorption and digestion can occur chyme= semi-fluid mixture that the food becomes when it is digested in the stomach

19. List the three major anatomical parts of the stomach.

a)fundus b) body c) antrum

which type of venous wave is caused by atrial contraction. Ordinarily, the right atrial pressure increases 4 to 6 mm Hg during atrial contraction, and the left atrial pressure increases about 7 to 8 mm Hg.

a-wave

11. Describe the five mechanisms that compensate for or correct circulatory shock.

a. Baroreceptor reflexes (Sym stimulation) b. CNS ischemic response (Sym stimulation at arterial pressure < 50 mm Hg) c. Renal effects (RAS/angiotensin formation): vasoconstriction and fluid/salt retention d. Catecholamine release from adrenal medulla (Sym stimulation) e. Vasopressin (ADH) release from posterior pituitary gland f. Other compensatory mechanisms to return blood volume back towards normal (eg., intestinal absorption of fluid, increased thirst and salt appetite).

drugs that stimulate the NMJ by inactivating acetylcholinesterase

a. reversible drugs -neostigmine -physostigmine b. irreversible poison - diisopropyl fluorophosphate (nerve gas) - causes muscle spasms

muscles of the middle ear (stapedius and tensor tympani, CN V, CN VII):

a.are always fully contracted to keep the tympanic membrane tensed; b.protect the cochlea from excessive stimulation; c. are necessary for auditory sensation; d.are reflexly activated by loud sounds.

Frequency Summation and Tetanization.

above are displayed individual twitch contractions occurring one after another at low frequency of stimulation. Then, as the frequency increases, there comes a point where each new contraction occurs before the preceding one is over. As a result, the second contraction is added partially to the first, so that the total strength of contraction rises progressively with increasing frequency. When the frequency reaches a critical level, the successive contractions eventually become so rapid that they fuse together, and the whole muscle contraction appears to be completely smooth and continuous, as shown in the figure. This is called tetanization.

4. What does the term absolute refactory period of the heart mean in electrical terms? What does the term, relative refractory period mean? When in the ECG is the heart relatively refractory?

absolute refractory period - interval of time, as shown to the left in Figure 9-4, during which a normal cardiac impulse cannot re-excite an already excited area of cardiac muscle. The normal refractory period of the ventricle is 0.25 to 0.30 second which is about the duration of the prolonged plateau action potential. relative refractory period - relative refractory period of about 0.05 second during which the muscle is more difficult than normal to excite but nevertheless CAN be excited by a very strong excitatory signal, as demonstrated by the early "premature" contraction

the numerous mitochondria in the axonal terminal cytoplasm generate ATP to be used in synthesis of what excitatory transmitter?

acetylcholine

thin filaments are what protein

actin

in the depolarization phase of action potential, the sodium channels are in what state

activated state

what develops on the waveform when the stimuli are below threshold required to eliciting AP?

acute sub-threshold potentials

The substance with most significant vasodilator property is

adenosine - With low concentration of O2 in cells, more ATP is degraded into adenosine, etc. - Adenosine acts rapidly on receptors in coronary bv to induce vasodilation; it is then degraded rapidly and also take-up by cells for reuse.

cortisol is released from what following input from what system to the hypothalamus

adrenal cortex following CNS input (stress) to the hypothalamus

what principle describes the principle for opening and closing of a channel?

all or none principle (recorded using the patch-clamp method)

name some cells located in the anterior horn of the spinal cord

alpha motor neurons gamma motor neurons interneurons renshaw cells

2. Define "insensible" water loss.

amount of H2O lost by evaporation through skin or respiratory tract = 700 mL/day; not aware of it; it is continuous...

Are the last small branches of the arterial system; act as control conduits through which blood is released into the capillaries; have strong muscular walls that can close the arterioles completely or can, by relaxing, dilate the vessels several folds, thus possessing the capability to vastly alter blood flow in each tissue in response to need.

arterioles

site of release of acetylcholine from synaptic vesicles

at the neural membrane of the neuromuscular junction

2 different syncytiums in heart

atrial and ventricular

When are all values closed? When are all valves open?

atrial systole - SL valves closed and AV valves open ventricular systole - SL valves open and AV valves closed

decrease in total mass of muscle is called

atrophy -When muscle remains unused for long enough, increased rate of decay of contractile proteins and in myofibrils occur more rapidly than replacement, causing muscle atrophy. One such aspect is denervation atrophy. If muscle is not used for 1-2 years, very difficult to replace lost fibers. -Additionally, when a muscle continually remains shortened to less than its normal length, sarcomeres at the ends of the muscle fibers can actually disappear. It is by this and similar processes that muscles are continually remodeled to have the appropriate length for proper muscle contraction.

unlike negative feedback (FB), positive FB generally leads to instability (pathology)...example of positive feedback mechanism that has a positive purpose?

blood clotting

5. What does a pulse rate of 50 beats a minute in a non-athlete suggest?

bradychardia - in the context of adult medicine, is the resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beats/min. It may cause cardiac arrest in some patients, because those with bradycardia may not be pumping enough oxygen to their hearts. It sometimes results in fainting, shortness of breath, and if severe enough, death

principle ion in action potential of cardiac muscle

calcium (sodium is present but not as big a role as calcium)

in small smooth muscle cells, even without an AP, the local depolarization caused by the nerve transmitter substance itself spreads "electrotonically" over the entire fiber and is all that is needed to cause muscle contraction; the extent of the local depolarization is referred to as?

called the junctional potential

Functioning to exchange fluid, nutrients, electrolytes, hormones, and other substances between the blood and the interstitial fluid. For this, capillary walls are very thin and have numerous minute pores permeable to water and other small molecular substances.

capillaries

t/f in most tissues, all vessels are innervated by sympathetic fibers except -

capillaries

in what type of AP is a plateau observed

cardiac AP - -This type of action potential occurs in heart muscle fibers, where the plateau lasts for as long as 0.2 to 0.3 second and causes contraction of heart muscle to last for this same long period.

2. What is the cardiac index?

cardiac index= CO per square meter of body surface area (a person weighing 70 kg has body surface area of 1.7 square meter, so his/her cardiac index= 3 L/min/m2).

GASTRIC ATROPHY

caused by chronic gastritis (gastric mucosa atrophies, or shrinks, until little or no activity remains) May also be caused by autoimmune disfunction -loss of G cells (reduced gastrin secretion) -achlorhydria (low H+ and pepsinogen secretion) -pernicious anemia (low intrinsic factor secretion) -increased risk of peptic ulcer

three phases of gastric secretion

cephalic gastric intestinal

second heart sound (dub) is caused by

closure of semilunar valves (aortic and pulmonary valves) at end of systole; second sound of heart. "... the cause of the sounds is vibration of the taut valves immediately after closure along with vibration of adjacent blood, walls of the heart, and major vessels around the heart."

Virtually all body movements are caused by simultaneous contraction of agonist and antagonist muscles on opposite sides of joints. This is called?

coactivation of the agonist and antagonist muscles, and it is controlled by the motor control centers of the brain and spinal cord. -The position of each separate part of the body, such as an arm or a leg, is determined by the relative degrees of contraction of the agonist and antagonist sets of muscles.

Troponin and Its Role in Muscle Contraction.

complexes of three loosely bound protein subunits, each of which plays a specific role in controlling muscle contraction. One of the subunits (troponin I) has a strong affinity for actin, another (troponin T) for tropomyosin, and a third (troponin C) for calcium ions. This complex is believed to attach the tropomyosin to the actin. The strong affinity of the troponin for calcium ions is believed to initiate the contraction process

• Amacrine cells (29 types)

connect ganglion cells to one another in the inner plexiform layer.

Horizontal cells

connect receptor cells to other receptor cells in the outer plexiform layer.

Most of the terminal axons in smooth muscle have multiple varicosities distributed along the axis; what is contained within them?

contain vesicles loaded with NT substances, which are release with stimulation.

Isovolumic contraction

contraction that does not show a change in volume

in the previous figure, the corticospinal tract is coming from where and does what in the figure/body?

corticospinal tract from the brain is shown to terminate almost entirely on spinal interneurons, where the signals from this tract are combined with signals from other spinal tracts or spinal nerves before finally converging on the anterior motor neurons to control muscle function.

8. Describe the CNS ischemic response (Cushing Reaction)

decreased blood flow to the vasomotor center and consequent nutritional deficiency (ie., cerebral ischemia), the vasoconstrictor and cardioaccelerator neurons in the vasomotor center becomes excited and responds directly. Consequently, the systemic arterial pressure rises and causes the heart to pump. This effect is partly caused by failure of the slowly flowing blood to remove carbon dioxide away from the vasomotor center. Other contributing factors, such as buildup of lactic acid and other acidic substances in the vasomotor center. This effect of ischemia is known as CNS ischemic response. The CNS ischemic response is considered to be one of the most powerful activators of the sympathetic vasoconstrictor system. However, the CNS ischemic response does not become significant until the arterial pressure falls far below normal (60 mm Hg or below). Thus, it is not a 'normal' mechanism for regulating arterial pressure, but it operates as an emergency pressure control system to prevent further reduction in pressure (when blood flow to the brain decreases alarmingly low). Increased pressure of the cerebrospinal fluid around the brain in the cranial vault causes Cushing reaction, a special type of CNS ischemic response. When the cerebrospinal fluid pressure rises to the level of arterial pressure, it compresses the brain and the arteries within. This cuts off the blood supply to the brain, initiating a CNS ischemic response with a rise in arterial pressure. When the arterial pressure rises above the cerebrospinal fluid pressure, blood flows once again into the vessels of the brain to relieve the ischemia. The Cushing reaction thus protect the vital centers of the brain.

Neuronal Circuitry of the Stretch Reflex (myotatic reflex)

demonstrates the basic circuit of the muscle spindle stretch reflex, showing a type Ia proprioceptor nerve fiber originating in a muscle spindle and entering a dorsal root of the spinal cord. A branch of this fiber then goes directly to the anterior horn of the cord gray matter and synapses with anterior motor neurons that send motor nerve fibers back to the same muscle from which the muscle spindle fiber originated. Thus, this is a monosynaptic pathway that allows a reflex signal to return with the shortest possible time delay back to the muscle after excitation of the spindle.

3. Define colligative property and give three examples of such properties.

depends on # of particles, not the kind -freezing point -boiling point -vapor presure

describe the safety factor for propagation

despite being an all or none mechanism, Occasionally, the action potential reaches a point on the membrane at which it does not generate sufficient voltage to stimulate the next area of the membrane. When this occurs, the spread of depolarization stops. Therefore, for continued propa- gation of an impulse to occur, the ratio of action poten- tial to threshold for excitation must at all times be greater than 1. This "greater than 1" requirement is called the safety factor for propagation.

6. diastole? sistole?

diastole - period of relaxation during which the heart fills with blood -followed by a period of contraction called systole.

10. How does one calculate stroke volume in terms of the difference between systolic and diastolic volume?

end-diastolic pressure (110-120 mL) - stroke volume output (70 mL) = end-systolic volume (40-50 mL)

9. What is the magnitude of the end diastolic volume? Of the end systolic volume?

end-diastolic volume - During diastole, normal filling of the ventricles increases the volume of each ventricle to about 110 to 120 mL. end systolic volume - The remaining volume in each ventricle after stroke volume is ejected, about 40 to 50 mL, is called the end-systolic volume. *When the heart contracts strongly, the end-systolic volume can be decreased to as little as 10 to 20 mL. Conversely, when large amounts of blood flow into the ventricles during diastole, the ventricular end- diastolic volumes can become as great as 150 to 180 milliliters in the healthy heart. By both increasing the end-diastolic volume and decreasing the end-systolic volume, the stroke volume output can be increased to more than double normal.

how do the synaptic vesicles deliver their cargo to the synaptic space?

exocytosis

Alpha (A) motor neurons are large (14 μM diameter) motor neurons that give rise to nerve fibers that innervate 'regular' skeletal muscle fibers called?

extrafusal fibers (myelinated)

most important heart sounds

first and second heart sound -av closure -valve closure

What produces the second heart sound? What event produces the first heart sound?

first heart sound - When the ventricles contract, one first hears a sound caused by closure of the A-V valves. The vibration is low in pitch and relatively long-lasting. second heart sound - When the aortic and pulmonary valves close at the end of systole, one hears a rapid snap because these valves close rapidly, and the surroundings vibrate for a short period.

Contracting end portions of the spindle (intrafusal) are stimulated by?

gamma (γ) motor nerve fibers (but the extrafusal muscle fibers are stimulated by alpha (α) motor nerve fibers).

what controls the Intensity of the Static and Dynamic Responses

gamma motor nerves -As the muscle at the 2 ends of the muscle spindle fiber contract by gamma neuron activation, they pull on the center of the spindle fiber and stretch the sensory receptors, causing activation. Activation of the spindle receptors by stretch causes increased rate of AP firing along the nerve fibers. -The gamma motor nerves to the muscle spindle can be divided into two types: gamma- dynamic (gamma-d) and gamma-static (gamma-s). The first of these excites mainly the nuclear bag intrafusal fibers, and the second excites mainly the nuclear chain intrafusal fibers. When the gamma-d fibers excite the nuclear bag fibers, the dynamic response of the muscle spindle becomes tremendously enhanced, whereas the static response is hardly affected. Conversely, stimula- tion of the gamma-s fibers, which excite the nuclear chain fibers, enhances the static response while having little influence on the dynamic response. Subsequent paragraphs illustrate that these two types of muscle spindle responses are important in different types of muscle control.

Micelles-

important in fat digestion. If free fatty acids from the breakdown of triglycerides were just floating around in the intestines, then digestion of fats would stop (negative feedback) Instead, they are pushed to the center of micelles, so that digestion continues uninterrupted. Also, micelles are important in Transport of fatty acids.

What variables influence the rate at which substances diffuse?

in simple diffusion, -No carrier protein is needed • The more lipid soluble a molecule (ie., less ionic/polar), the more permeant it is through the lipid bilayer. • The smaller the molecule/ion, the more permeable it is through protein channels/pores (and vice versa).

12. What is a prolapsed valve? What are its functional consequences? Clinical consequences? When should you give patients with prolapsed mitral valves antibiotic coverage?

in vanes of A-V node; chordae tendineae. The papillary muscles contract when the ventricular walls contract, but contrary to what might be expected, they do not help the valves to close. Instead, they pull the vanes of the valves inward toward the ventricles to prevent their bulging too far backward toward the atria during ventricular contraction. If a chorda tendinea becomes ruptured or if one of the papillary muscles becomes paralyzed, the valve bulges far backward during ven- tricular contraction, sometimes so far that it leaks severely and results in severe or even lethal cardiac incapacity.

GASTRITIS

inflammation of the gastric mucosa -caused by bacteria -exacerbated by alcohol, aspirin, HF -chronic gastritis can cause gastric atrophy

how are separate motor units typically arranged

interdigitating arrangement allows the separate motor units to contract in support of one another rather than entirely as individual segments.

-The Macula

is the area of the retina that surrounds the fovea centralis - with age, our eyes adapt to the dark more slowly

which one of the two systems for recording two types of muscle contraction is most often used when comparing the functional characteristics of different muscle types?

isometric system is most often used when comparing the functional characteristics of different muscle types -In the isometric system, the muscle contracts against a force transducer without decreasing the muscle length. -In the isotonic system, the muscle shortens against a fixed load; this is illustrated on the left in the figure, showing a muscle lifting a pan of weights. The characteristics of isotonic contraction depend on the load against which the muscle contracts, as well as the inertia of the load. -However, the isometric system records strictly changes in force of muscle contraction itself. Therefore, the iso- metric system is most often used when comparing the functional characteristics of different muscle types.

when muscle does shorten but the tension on the muscle remains constant throughout the contraction.

isotonic -Isotonic contraction means "same tone" -force is constant -In isotonic contraction, a load is moved (which involves inertia) and there is performance of external work, which requires greater amount of energy.

When does the heart undergo isovolumic contraction in terms of the cardiac cycle? What is isovolumic relaxation of the heart and when does it occur?

isovolumic contraction - during this period, contraction is occurring in the ventricles, but there is no emptying; aka isometric contraction, meaning that tension is increasing in the muscle but little or no shortening of the muscle fibers is occurring. isovolumic relaxation - At the end of systole, ventricular relaxation begins suddenly, allow- ing both the right and left intraventricular pressures to decrease rapidly. The elevated pressures in the dis- tended large arteries that have just been filled with blood from the contracted ventricles immediately push blood back toward the ventricles, which snaps the aortic and pulmonary valves closed. For another 0.03 to 0.06 second, the ventricular muscle continues to relax, even though the ventricular volume does not change, giving rise to the period of isovolumic or iso- metric relaxation. During this period, the intraventricular pressures decrease rapidly back to their low diastolic levels. Then the A-V valves open to begin a new cycle of ventricular pumping.

Certain organs need blood flow regulation to serve special purposes. Examples:

kidney to adequately/rapidly excrete wastes

describe the molecular basis of the "length-tension diagram".

length-tension diagram for a single fully contracted sarcomere, showing maximum contraction when the sarcomere is 2.0 to 2.2 mm in length. At the upper right are the relative positions of the actin and myosin filaments at different sarcomere lengths from point A to point D.

The normal concentration of Ca2+in the cytosol is

low (<10-7 M), but during excitation it can rise as high as 2x10-4M.

8. List three factors that can alter urinary pH and state whether these would increase or decrease the renal clearance rate of fluoride.

lowering the pH like in protein diet might increase F retention

-central lacteal (part of absorptive anatomy)

lymphatic vessel in each intestinal villus that take fat absorbed by the intestinal epithelium and place it into lymphatic circulation

8 essential amino acids are:

lysine, methionine, threonine, valine, leucine, isoleucine, phenylalanine, and tryptophan.

t/f Abnormal production of hormones can cause various diseases which can influence dental treatment- eg., hyperthyroidism or hypothyroidism, hypoinsulinemia (diabetes), etc.

major endocrine glands

What does muscle pain do to the "chewing envelope"?

makes it smaller

What organelle is present is tremendous numbers and lie parallel to the myofibrils?

mitochondria are present in tremendous numbers and lie parallel to the myofibrils. These supply the contracting myofibrils with large amounts of energy in the form of adenosine triphosphate (ATP) formed by the mitochondria.

Each motoneuron that leaves the spinal cord innervates multiple muscle fibers, the number depending on the type of muscle. All the muscle fibers innervated by a single nerve fiber are called a

motor unit (includes muscle fibers and innervating nerve fiber) In general, small muscles that react rapidly and whose control must be exact have more nerve fibers for fewer muscle fibers (for instance, as few as two or three muscle fibers per motor unit in some of the laryngeal muscles). Conversely, large muscles that do not require fine control, such as the soleus muscle, may have several hundred muscle fibers in a motor unit. An average figure for all the muscles of the body is questionable, but a good guess would be about 80 to 100 muscle fibers to a motor unit.

effects of muscle denervation

muscle denervation atrophy -muscle loses its nerve supply, it no longer receives the contractile signals that are required to maintain normal muscle size; atrophy begins almost immediately. -after about 2 months, degenerative changes also begin to appear in the muscle fibers themselves. -If the nerve supply to the muscle grows back rapidly, full return of function can occur in as little as 3 months, but from that time onward, the capability of functional return becomes less and less, with no further return of function after 1 to 2 years. -In the final stage of denervation atrophy, most of the muscle fibers are destroyed and replaced by fibrous and fatty tissue. The fibers that do remain are composed of a long cell membrane with a lineup of muscle cell nuclei but with few or no contractile properties and little or no capability of regenerating myofibrils if a nerve does regrow. -The fibrous tissue that replaces the muscle fibers during denervation atrophy also has a tendency to continue shortening for many months, which is called contracture. Therefore, one of the most important problems in the practice of physical therapy is to keep atrophying muscles from developing debilitating and disfiguring contractures. This is achieved by daily stretching of the muscles or use of appliances that keep the muscles stretched during the atrophying process.