Units 1, 2, 3, 4 & 5
How are free fatty acids and monoglycerides transported to the liver?
Chylomicrons travel through the lymphatic system and enter the venous blood returning to the heart
15. Which muscle controls the shape of the lens and the tension on the zonular fibers?
Ciliary muscle
1. Where are sympathetic ganglia, in comparison to parasympathetic ganglia? Describe the autonomic motor pathway from the cns to the effector organ.
Cns ---> preganglionic (cns)---> ganglion ---> postganglionic (pns) ---> effector organs (smooth muscle, cardiac muscle and glands, neurons in gi tract)
1. What two parameters determine blood pressure by altering blood volume?
Co, tpr
2. which chemical equation supports this?
Co2 + h2o ↔ h2co3 ↔ hco3- + h+
3. How would you describe a column in the spinal cord?
Columns contain tracts of distinct bundles of cns nerve axons that have a common origin or destination and carry similar information.
5. Which two factors most affect the percentage of saturation?
Concentration of unbound ligand in the solution, compared to number of binding sites or proteins • If more ligand is present more is available to bind • If the binding sites are completed saturated additional ligand will not be able to bind Affinity of the binding site for the ligand • Correct shape and opposite charge will produce the highest affinity ensuring a higher percentage of saturation
11. How is the anatomical dead space related to gas exchange?
Conducting zone, which does not permit gas exchange with the blood is known as anatomical dead space.
What parts of the bronchial tree are considered to be the anatomical dead space?
Conducting zone: trachea, bronchi, down to the terminal bronchioles
5. What are the functions of connective tissue?
Connective tissue connects, anchors and supports the structures of the body.
5. What is the role of calcium in cardiac muscle action potential?
Continued depolarization - voltage-gated l(long-lasting)-type ca++ channels open slowly and stay open for a long time
19. Explain the following statement: "a change in contraction force due to increased end-diastolic volume (the frank-starling mechanism) does not reflect increased contractility".
Contractility is independent of changes in volume. It refers to increased contraction force at a given edv. E.g., the same volume with sns input would result in a stronger contraction.
2. What is meant by the term "signal transduction"?
Conversion of a signal from outside the cell (stimulus) to a functional change (response) within the cell
9. What happens to vitamin d in the kidneys? Why is this important?
Converted into calcitriol; calcitriol is a hormone that stimulates calcium absorption in the intestines
3. How does hemoglobin's affinity change upon the addition of one oxygen molecule? What do you call this characteristic?
Cooperativity: binding of one oxygen molecule to deoxyhemoglobin increases affinity for the remaining sites. Globin units of deoxyhemoglobin are tightly held by electrostatic bonds in a conformation with a relatively low affinity for oxygen. O2 binding breaks some of the bonds, leading to a conformation change leaving remaining-oxygen binding sites more exposed.
6. Optional: when and from what does the corpus luteum form?
Corpus luteum forms from the remnants of the follicle after ovulation
2. What is the role of ca2+ in neurotransmitter release from the presynaptic cell?
Ca++ needs to bind in order for the vesicles to bind and release nt into the cleft
Which sections of the tubule exhibits the greatest fluctuation in osmolarity due to water reabsorption?
Descending limb of the lh and medullary collecting duct
9. How are desmosomes different from tight junctions? Be specific.
Desmosomes • Provide a firm attachment acting like spot welds • Characterized by dense plaques composed of the protein cadherin and keratin filaments • A small space remains between the cells when the desmosome is formed • Located in areas where there is considerable stretching, e.g. Skin Tight junctions • Provide a band around the entire circumference of the cell • No extracellular space between, so most molecules cannot pass with the exception of some ions and water • Located often between epithelial cells in the intestine
8. Identify the three major types of junctions.
Desmosomes, tight junctions, and gap junctions
1. What effect would diarrhea have on h+ concentration?
Diarrhea causes a loss of hco3- which would increase h+ concentration
a. Which one is associated with blood filling?
Diastole
h. Does rapid filling of the ventricles occur in systole or diastole?
Diastole
3. Which area of the brain consists of structures that relay signals, regulate neural and endocrine function, and control the biological rhythm?
Diencephalon
When considering the flow of air in the lungs, what pressures are considered in the f = "δp" /"r" formula?
F = (palv - patm)/r Alveolar pressure and atmospheric pressure
How is flow related to velocity and area?
F = v x a (f = flow, v = mean velocity, and a = cross-sectional area of the vessel)
4. What hormone stimulates follicular growth during the early and middle follicular phases?
FSH
3. What are the two types of mediated-transport?
Facilitated diffusion Active transport
6. Refer to your lecture notes for this question: describe the relationship between "facilitated diffusion", "mediated transport", and "passive transport".
Facilitated diffusion is passive transport, because it does not use atp but does use transport proteins. Mediated transport uses shape-changing transport proteins and includes atp-using and non-atp-using transport proteins. Carriers fall under both facilitated diffusion and mediated transport.
14. Optional: where does fertilization occur? Where does the embryo grow?
Fallopian tube (too late if fertilized in uterus) Grows in the uterus, after developing in transit from fallopian tube to the uterus
5. True or false - if false, change it to make it correct. a) Peripheral resistance decreases with increasing blood vessel length.
False, resistance will increase
5. True or false - if false, change it to make it correct. b) Peripheral resistance decreases if blood vessel diameter is reduced by 50%.
False, resistance will increase
5. True or false - if false, change it to make it correct. c) Peripheral resistance decreases in cases of polycythemia (more red blood cells).
False, resistance will increase
23. Compare and contrast myopia (nearsightedness) and hyperopia (farsightedness) in terms of eye anatomy, ability to see distant or near objects, image position in reference to the retina, and correction. (farsightedness)
Farsightedness • Eye anatomy-eyeball too short • Can't see near objects clearly; can see far objects clearly • Image falls as if in back of the retina • Correction - convex lens
5. What are the differences between the stress responses of adrenal medulla versus adrenal cortex?
Fast versus slow Short-lived versus sustained Direct effect (e.g. dilate blood vessels in brain and muscle) versus indirect (e.g. sensitize blood vessels)
23. What factors increase cardiac output?
Fig 12-51
24. (review) what factors increase total peripheral resistance?
Fig 12-51
2. Explain the mechanism by which the na+-k+-atpase establishes and maintains the resting membrane potential (see figure 6-13).
First, the action of the na+/k+-atpase pump sets up the concentration gradients for na+ and k+: 3 na+ on the outside and 2 k+ on the inside. This makes the icf slightly more negative compared to the ecf. At the same time, there is a greater flux of k+ out of the cell than na+ into the cell due to a greater number of open k+ channels than na+ channels. Na+ is trapped on the outside because the cell has very few na+ leak channels. Because there is greater net efflux than influx of positive ions, a significant negative membrane potential develops, with the value approaching that of the k+ equilibrium potential. The na+/k+ pump maintains the rmp by maintaining the concentration gradients of na+ and k+. The movement of ions through the na+/k+-atpase pump perfectly balances the rate of ion leakage through channels.
5. Which commonly used term describes the general structure of the cellular membrane? What does it mean that it's fluid? What does it mean that it's mosaic?
Fluid-mosaic model: fluid, because phospholipids move around. Mosaic, because there are phospholipids and many different kinds of proteins
d. When are the semilunar valves closed?
Isovolumetric relaxation, ventricular filling, isovolumetric contraction
9. How does the state of polarization of photoreceptors compare to other sensory receptors?
Most sensory receptors are depolarized when stimulated, not hyperpolarized
1. Optional: identify the four main layers of the intestinal wall.
Mucosa, submucosa, muscularis externa, and serosa
5. Identify the three mechanisms through which sodium depletion causes an increase in renin secretion.
(1) stimulation of the renal sympathetic nerves to the juxtaglomerular cells by extrarenal baroreceptor reflexes (2) pressure decreases sensed by the juxtaglomerular cells, themselves acting as intrarenal baroreceptors; bp decreases, cells are stretched less, secrete more renin (3) a signal generated by low sodium or chloride concentration in the lumen of the macula densa as it senses na+ concentration as fluid flows by
7. Which factors are the most important in determining pulse pressure?
(1) stroke volume - volume increases, then pp increases (2) speed of ejection of the stroke volume - speed increases, then pp increases (3) arterial compliance - compliance increases, then pp decreases
11. The lack of atp contribute to rigor mortis. What is atp's relationship to the cross bridge cycle? Using that information, explain how the lack of atp contribute to rigor mortis.
---When atp binds to myosin, it lets go of the actin (i.e. Atp acts as a cessation of cross-bridge) ---Without atp, the actin remains bound to the myosin, so there is no relaxation. This is why muscles are stiff in rigor mortis.
6. What is the extracellular matrix? Where is the extracellular matrix? (remember ecm = ecf)
-A complex consisting of a mixture of proteins, polysaccharides, and in some cases, minerals interspersed with extracellular fluid -Outside the cells
5. Describe how a ligand-gated channel works. Ligand-gated channels are found in ... which step in figure 6-27?
-A ligand-gated channel opens when a ligand binds to it. -E shows the neurotransmitter acting as a ligand for the receptor, which is a ligand-gated sodium channel.
1. What is the basement membrane? What is its function?
-An extracellular protein layer -To anchor the cells
7. What is adaptation of the sensory receptor?
-Decrease in receptor sensitivity -Decrease in action potential frequency despite constant stimulus strength
3. How does the function of a dendrite differ from the function of an axon?
-Dendrites receive input - chemical message (nt) received and converted into electrical message; -Axons send output - electrical message carried to the axon terminal so chemical message (nt) can be released to target cells (muscle, glands, other neurons).
2. Give at least two examples proving the fact that not all cranial nerves are mixed nerves.
-Only efferent (hypoglossal) -Only afferent (optic, olfactory)
2. What is the difference between positive and negative feedback? Give a step-by-step example of each.
-Positive feedback system - a response enhances the effect of the stimulus - increases or decrease in a variable brings about responses to move the variable in the same direction (oxytocin during labor-see text for an example) -Negative feedback - a response reverses the effect of the stimulus - increases or decrease in a variable brings about responses to move the variable in the opposite direction (enzymatic processes, thyroid hormone level control, bp control-see textbook for an examples)
1. What are the three main components of a feedback look or reflex arc, and what are their functions?
-Receptor - monitors a controlled condition -Control center - determines next action -Effector - receives directions from the control center and produces a response that changes the controlled condition
1. What is the difference between steady state and equilibrium? Give an example of system that is in a steady state.
-Steady state - a system in which no variable is changing but energy must be added to maintain a constancy, i.e. Dynamic equilibrium; e.g. Maintaining body temperature when the temperature externally is changing, the body initiates mechanisms to counteract this to keep the internal temperature constant -Equilibrium - a system in which no variable is changing and no energy is required to maintain the constancy
6. How does the stimulus intensity (or stimulus strength) affect the sensory neurons' action potentials?
-The stronger the stimulus, the stronger the receptor potential (graded potential) -The magnitude of receptor potential determines the frequency of the action potentials, but not the magnitude of the action potential.
9. Which hormones are quicker-acting and shorter-lived? Why?
-Water-soluble is quicker-acting because their response usually does not require/involve gene expression change (only cascade of proteins) -Water-soluble is shorter-lived for the same reason - gene expression change is long-term
14.8 - renal sodium regulation
1. A decrease in total body sodium is correlated with (choose one: high or low) plasma volume?
2. There are two basic types of sensory receptors. a. How do they differ anatomically? b. What is an example of each?
1. An ending of an afferent neuron, like touch receptors in skin 2. A separate cell adjacent to afferent neuron, like hair cells in ear
8. Summarize sound transmission in the ear.
1. Auricle collects sound waves and passes them inwards through the external auditory canal. 2. When the sound waves hit the tympanic membrane (eardrum) it vibrates. 3. Ossicles vibrate since malleus is attached to the eardrum. 4. Stapes pushes on oval window. 5. Fluid pressure waves develop in scala vestibuli and tympani. 6. Pressure fluctuations inside cochlear duct move the hair cells against the tectorial membrane. 7. Tectorial membrane vibrates. 8. Hair cells bend, letting potassium into cell. 9. Hair cells release neurotransmitter. 10. Auditory nerve generates an action potential which travels into the cns.
9. Which factors lead to the medullary interstitial fluid becoming hyperosmotic?
1. Countercurrent anatomy of the loop of henle of juxtamedullary nephrons 2. Reabsorption of nacl in the ascending limb of lh 3. Impermeability to water in the ascending limb of lh 4. Trapping of urea (osmotically active) in the medulla 5. Hairpin loops of vasta recta to minimize washout of the hyperosmotic medulla (minimizes excessive loss of solute) vessels run parallel to lh
10. Describe the cross-bridge cycle in detail.
1. Cross-bridges are considered to be energized when atp has split into adp and phosphate. The products of the split are still attached to the myosin. 2. When ca2+ enters the cytoplasm, energized myosin can bind to actin. 3. The binding of myosin to actin triggers a power stroke and the release of phosphate and adp. Actin and myosin remain bound. 4. The binding of atp breaks the myosin and actin attachment. This is a form of allosteric modulation. 5. Once actin and myosin have detached, the atp bound to myosin is hydrolyzed into phosphate and adp. The cross-bridge has returned to its energized state.
7. Describe three ways to terminate a signal in a chemical synapse.
1. Diffusion of the transmitter from the synaptic cleft into ecf 2. Enzymatic degradation and recycling of the transmitter 3. Reuptake into the pre-synaptic cells for reuse
6. What is the role of calcium in sa node action potential?
1. During depolarization to threshold, t (transient)-type ca++ channel open briefly, providing a depolarizing boost. 2. (same as in contractile cardiac mucsle cell) l-type ca++ channels open
2. Reabsorption of bicarbonate is different from reabsorption of other substances. Describe the process of bicarbonate reabsorption.
1. Intracellularly co2 and h2o combine to form h2co3 catalyzed by carbonic anhydrase 2. H2co3 dissociates to h+ and hco3- 3. Hco3- moves via facilitated diffusion (high to low) across basolateral membrane into isf and then into blood 4. Simultaneously, h+ is secreted into the lumen via active transport 5. Secreted h+ is not excreted, but instead combines with hco3- to form h2o and co2 6. Both h2o and co2 diffuse back into the cell • The hco3- filtered at the glomerulus has been utilized to produce co2 and h2o, so the hco3- produced within the cell is replaced. • There is no net change as normally the kidneys reabsorb all filtered hco3- preventing the loss in the urine.
1. Do baroreceptors set long-term arterial pressures? Explain.
Baroreceptors do not set long-term arterial pressures. They adapt to short-term changes in pressure.
13. What are the three types of inputs that can regulate release of hormones? Which type of input regulates pancreatic endocrine cells? Which regulate parathyroid cells? Which regulate the thyroid? Which regulate the adrenal medulla? Adrenal cortex?
1. Ion/nutrient directly sensed by the endocrine cell 2. Neurotransmitter from the nervous system 3. Another ("upstream") hormone • Ion/nutrient concentration regulates parathyroid cells - specifically, plasma calcium ion concentration does • Another hormone regulates thyroid (follicle) cells - specifically, tsh from the anterior pituitary regulates the thyroid • Neurotransmitter regulates adrenal medulla - specifically, the sympathetic nervous system Another hormone regulates adrenal cortex - specifically, acth from the anterior pituitary
3. How is pth different to aldosterone?
1. K+ and na+ are "opposites" to begin with, whereas ca2+ and po4- go together -Aldosterone has direct impact on k+ (decrease) and na+ (increase), but pth decreasing po4- balances out responses elsewhere in the body that increases it along with ca2+ (thus, pth has a stabilizing effect on po4-) 2. Aldosterone secretion is stimulated by high levels of plasma k+ which aldosterone action decreases, whereas pth secretion is stimulated by low levels of plasma ca2+
1. Name the main parts of the urinary system in order, starting with renal corpuscle and ending with urethra.
1. Renal corpuscle 2. Proximal convoluted tubule 3. Loop of henle 4. Distal convoluted tubule 5. Collecting duct system 6. Renal pelvis 7. Ureter 8. Bladder (detrusor muscle in the bladder contracts) 9. Urethra
9. Apply labels to the figure of the na+/k+-atpase pump below differentiating between the ions, ion concentrations, intracellular space, extracellular space, and energy molecule. Try to label it yourself and then check it against figure 4-11 in the book. You should also describe each step in words.
1. Transporter with intact molecule of atp attached binds three na+ ions on intracellular side of the protein (high-affinity for na+) 2. Binding of na+ results in atpase activity causing a breaking of the 3rd phosphate bond on the atp. This results in phosphorylation of the transporter and a release of adp. 3. Phosphorylation causes a conformational change, exposing the ions to the ecf fluid and reducing affinity for na +, so it is released. 4. New conformation results in an increased affinity for k+ allowing two k+ to bind to the transporter on the ecf side. 5. Binding of k+ results in dephosphorylation of the transporter. Transporter returns to original conformation with decreased affinity for k+, so k+ ions are released into icf. New molecules of na+ and atp are now able to attach.
2. Describe the three factors that determine the magnitude of flux in a mediated-transport system.
1. Transporters are specific for their ligand. 2. Transporters are slower than simple diffusion. They do not move as many molecules as channels because of binding and conformational shifts. 3. Transporters can be saturated. This means that there is a maximum flux of molecules that can be reached.
7. What is meant by "shift to the right" when referring to the oxygen-hemoglobin dissociation curve?
A shift to the right will signify that the affinity for oxygen is decreasing, causing the hb to be less saturated at any given po2.
6. What events cause the heart sounds? During which phase is the 1st heart sound heard?
1st: av valves closing 2nd: semilunar valves closing
9. Referring to figure 17-19, describe what causes the changes in fsh, lh, and estrogen at points 5-8. Which processes are due to negative feedback and which to positive feedback?
5: estrogen starts increasing due to growth of follicle and granulosa cell multiplication 6: fsh and lh switch from being inhibited (negative feedback) to being stimulated (positive feedback) 7 and 8: lh surge immediately followed by estrogen peak
1. Are there more glial cells or more neurons in the nervous system?
90% of cns cells are glial cells, only 10% are neurons
1. Use figure 13-21 to indicate < (less than), > (greater than), or = (equal to) for each pair: a) Po2 in the arterial end of the pulmonary capillaries ____ po2 in the alveoli
<
1. Use figure 13-21 to indicate < (less than), > (greater than), or = (equal to) for each pair: c) Po2 in the systemic veins ____ po2 in the systemic arteries (why?)
< <---->O2 diffused down the concentration gradient at the systemic capillaries because cells are using o2 and lowering their po2
1. Use figure 13-21 to indicate < (less than), > (greater than), or = (equal to) for each pair: b) Po2 in the pulmonary veins ____ po2 in the systemic arteries
=
1. Use figure 13-21 to indicate < (less than), > (greater than), or = (equal to) for each pair: e) Pco2 in the systemic veins ____ pco2 in the pulmonary arteries
=
1. Use figure 13-21 to indicate < (less than), > (greater than), or = (equal to) for each pair: d) Pco2 in the arterial end of the pulmonary capillaries ____ pco2 in the alveoli
>
1. Use figure 13-21 to indicate < (less than), > (greater than), or = (equal to) for each pair: f) Pco2 in the systemic veins ____ pco2 in the systemic arteries (why?)
> <----> Co2 diffused down the concentration gradient at the systemic capillaries because cells are making co2
4. Describe excitation-contraction coupling in cardiac muscle.
A cardiac muscle cell membrane action potential propagates through t-tubules as in skeletal muscle. Depolarization occurs due to an influx of sodium, but also ca++ through voltage-gated channels. L (long-standing)-type ca++ channels also trigger release of more ca++. Contraction is dependent on ca++ moving into the cytosol. Ca++ release into the cytosol is dependent on the movement of ec ca++ into the cytosol triggering release of more ca++ from the sarcoplasmic reticulum. Calcium leads to the binding site being uncovered on the actin. Actin and myosin bind and contraction occurs.
10. What is a target cell?
A cell that has the receptor for the chemical messenger
8. How does arteriosclerosis affect arterial compliance?
A decrease in arterial compliance occurs in arteriosclerosis (stiffening of the arteries). With age and arteriosclerosis sbp will increase and dbp will decrease. Pulse pressure will increase.
1. How would excessive sweating affect osmoreceptors and baroreceptors?
A decrease in body water raises body fluid osmolarity, so there is increased firing of the osmoreceptors and increase adh release. A decrease in body water decreases blood volume and pressure, so there is decreased firing of the baroreceptors and increased adh release.
3. What effect does a decrease in gfr have on sodium excretion?
A decrease in gfr leads to less filtration, so there would be less sodium in the tubules to be excreted
2. Define / describe a neurotransmitter.
A neurotransmitter is a molecule released from a synaptic vesicle that excites or inhibits postsynaptic neurons, muscle fibers or glands.
1. What is homeostasis?
A relatively stable condition of internal environment that results from regulatory system actions
3. Where does the apical side face?
Exterior towards the lumen
2. Draw a myofibril and label sarcomeres. What is a sarcomere?
A single unit of the repeating fiber pattern within a myofibril
Describe a synapse. In your answer, include presynaptic neuron and from a post-synaptic cell.
A synapse is an anatomically specialized junction between two neurons (presynaptic and postsynaptic neurons) or between a presynaptic neuron and an effector such as a muscle or gland, whereby the activity of one neuron alters the electrical and chemical activity of a second neuron, gland, or muscle.
2. What does dynamic constancy mean?
A way of describing homeostasis that includes the idea that a variable such as blood glucose may vary in the short term but is stable and predictable when averaged over the long term
1. Optional: define the following terms. Try to do it in your own words.
A. Depolarize - membrane potential becomes less negative closer to zero B. Overshoot - refers to reversal of membrane potential polarity; inside more positive relative to the outside C. Repolarize - membrane potential returns towards resting value D. Hyperpolarized - membrane potential becomes more negative than resting level E. Threshold stimuli - stimulus that can elevate the membrane level past threshold F. Threshold potential - membrane potential at which an action potential is initiated
3. What is acetylcholine and why is it important?
Acetylcholine is the nt at the nmj - controls all skeletal muscles. It's also used by autonomic ns as the first (preganglionic) nt.
3. What role does the pancreas have in neutralization of the chyme as it moves into the small intestine?
Acidic chyme from the stomach is neutralized by bicarbonate (hco3-) in the pancreatic fluid.
8. What is meant by a non-CO2 acid?
Acids (Or sources of H+) other than Carbonic Acid, like ketoacids
3. Identify and describe the two contractile proteins. Does each protein become shorter? Is that why they're called "contractile"?
Actin • Thin • Contractile protein • Each actin has a binding site for myosin • Interacts with regulatory proteins Myosin • Thick • Contractile protein • Contains a cross-bridge • Two binding sites ------One for actin ------One for atp - binding site serves as an atpase They slide past each other, so the sarcomere gets shorter. Each protein does not become shorter. They're called contractile because their sliding movements allow the whole muscle fiber to contract, not because they themselves get shorter.
5. Can action potentials be summed (summation)? Does muscle action potential experience 'summation'? Does muscle tension experience 'summation'? (extra: compare and contrast this with postsynaptic potential summation?)
Action potentials cannot be summed, so muscle action potentials can't be summed either. But - yes, muscle tension summates, until it reaches fused tetanus Extra: similarity is that both experience summation. This is different from postsynaptic potential summation because there is no negative tension like there is ipsps, and psps do not build up to a tetanic state.
7. Explain why action potentials are unidirectional down an axon.
Action potentials in neurons are unidirectional because as the action potential moves along the axon the membranes previously depolarized are now in an absolute refractory period. If the previous areas of membrane are in a refractory period, the signal cannot go back. The signal will continue away from the refractory period.
8. Describe saltatory conduction.
Action potentials occur only at the nodes of ranvier, where the myelin coating is interrupted and the concentration of voltage-gated na+ channels is high. Consequently, action potentials jump from one node to the next as they propagate along a myelinated fiber, and for this reason such propagation is called saltatory conduction.
1. Arteriole nick name: arterioles act as ________. This means...
Adjustable nozzles / arterioles control minute-to-minute blood flow into the capillary beds. If they constrict, blood flow is diverted away from the tissue; if they dilate, then blood flow to the tissue increases.
9. Which hormone is directly responsible for increased reabsorption of sodium?
Adrenal cortical hormone aldosterone.
2. What is an adrenergic neuron?
Adrenergic neurons release epinephrine, norepinephrine, or dopamine
2. How do the terms "afferent" and "efferent" relate to "sensory" and "motor"? Choose "sensory" or "motor" for each.
Afferent fibers (sensory, incoming from periphery to brain via spinal cord) enter the spinal cord from the peripheral nerves. These fibers enter on the dorsal side of the cord via the dorsal roots and synapse in the dorsal root ganglia.
1. What are the three functional classes of neurons?
Afferent, efferent, interneuron
10. Where in the tubules is sodium reabsorption increased through the action of aldosterone?
Aldosterone stimulates sodium reabsorption in the cortical collecting ducts and distal convoluted tubule.
7. Which types of muscle require increased cytosolic calcium to produce a contraction?
All
1. Which of the following hormones are found in males? Found in females? Gnrh Fsh Lh Androgens (testosterone and dihydrotestosterone) Estrogens (primarily estradiol) Progesterone
All are found in both sexes, but more androgens in males and more e & p in females
17. What happens to stroke volume, force or tension if edv increases according to the frank-starling mechanism?
All will increase
2. You should have identified "changing protein shape" as one of your answers for the previous question. There are two ways that protein shape can be changed for controlling activity. Compare and contrast allosteric and covalent modulation.
Allosteric modulation • Non-covalent binding of a ligand to one site can alter the shape of the second binding site, and therefore limit binding to that site Covalent modulation • Covalent bonding of charged chemical groups to some of the protein's side chains alters the charge distribution, and induces a conformational change which increases or decreases affinity
7. during expiration, how does the alveolar pressure compare to the atmospheric pressure?
Alveolar pressure is greater than atmospheric pressure during expiration.
5. During inspiration, how does the alveolar pressure compare to the atmospheric pressure?
Alveolar pressure is more negative or less than atmospheric pressure during inspiration.
2. How can you use the concepts of filtration, reabsorption and secretion to determine the amount of a substance excreted in urine?
Amount excreted = amount filtered + amount secreted - amount reabsorbed
3. What is osmotic pressure?
Amount of pressure that would have to be applied to a solution to prevent the net flow of water into the solution; ↑ osmolarity (more solute) = ↑ osmotic pressure
3. A membrane is found to be absolutely refractory to depolarization
An action potential will not be produced
1. Do you need one or many epsps to produce an action potential?
An ap can only be initiated by the combined effects of many excitatory synapses - voltage of a single epsp isn't high enough to reach threshold
2. How would an increase in plasma volume affect the gfr?
An increase in plasma volume would increase gfr
6. What is the consequence of channel opening in step e of figure 6-27? You must use the term 'electrochemical gradient' in your answer.
An influx of sodium ions because of the electrochemical gradient of sodium favors its entry (lots of sodium in ecf vs very little in icf, and negative rmp vs positively charged na+)
20. Describe the changes in the eye that lead to a cataract.
An opacity on the lens causes the lens to be cloudy; associated with aging, smoking, and diabetes; lens can be removed surgically and replaced with an artificial lens
11. What are three types of hormone-hormone interactions? Describe and give an example of each.
Antagonistic Permissive Synergistic
3. Which part of the pituitary gland is considered to be a true gland? Why?
Anterior pituitary (adenohypophysis) because hormones are synthesized here
12. An imbalance in the plasma levels of hydrogen affect absorption, how?
Appropriate levels of hydrogen are necessary to maintain the concentration gradients utilized for secondary active transport of amino acids. (low level of hydrogen would also decrease chemical digestion - separate from absorption)
11. An imbalance in the plasma levels of sodium affect absorption. How?
Appropriate levels of sodium are necessary to maintain the concentration gradients utilized for secondary active transport of monosaccharides and amino acids.
3. Astrocytes are the most versatile type of glia. D. How do they interact with neurons during development?
Astrocytes direct developing cells to destinations and secrete growth factors during development.
3. Astrocytes are the most versatile type of glia. B. what is the role of the astrocytes for the ecf?
Astrocytes help regulate composition of ecf in the cns by removing potassium (k+) ions and neurotransmitters around synapses.
3. Astrocytes are the most versatile type of glia. C. How do they contribute to the metabolic processes in neurons?
Astrocytes provide nutrients and remove waste from neurons. For example, astrocytes provide glucose and remove ammonia from neurons.
2. What are the four types of glial cells in the cns?
Astrocytes, ependymal cells, oligodendrocytes, microglial
18. What happens to edv, sv, and co if venous return is increased?
At a given hr, an increase in venous return to the heart causes increase in edv, sv, and co.
now describe in words what happens in terms of ion permeability in a cardiac muscle potential.
At rmp, the myocyte is much more permeable to k+ than to na+. During the depolarizing phase, voltage-gated na+ channels open as the membrane becomes more permeable to sodium. Permeability of k+ decreases as leaky k+ channels close. K+ channels stay closed during continued depolarization. There is an increase in cell permeability to ca++ manifested by the opening of voltage-gated l(long-lasting)-type ca++ channels. These open slowly and stay open longer. Na+ channels are rapidly closing during this time. At repolarization, there is a slow inactivation of ca++ channels, while k+ channels open. Sodium channels are closed.
11. What is an atpase?
Atpases are a class of enzymes that catalyze the breakdown of atp into adp and a free phosphate ion.
14. Where is anp being secreted from?
Atrial natriuretic peptide (anp) is secreted by cells in the atria in response to atrial distention as a result of increased plasma volume (increased na+).
g. Which valves are open during ventricular filling?
Atrioventricular valves - tricuspid and bicuspid
9. How is the motor end plate affected in myasthenia gravis?
Autoantibodies block the ach receptors at the neuromuscular junction. Muscles will weaken as contractions will lessen.
What is meant by "intrinsic tone"?
Basal level of contractile activity in the smooth muscle
2. Which side of the cell faces the basement membrane?
Basolateral (interior)
14. Why do some people have the same pulmonary or minute ventilation, but not the same alveolar ventilation?
Because alveolar ventilation takes dead space into account
10. Referring to figure 17-22, describe the relationship between fsh and estrogen (and progesterone) at points 15 and 16.
Before 15, corpus luteum's estrogen+progesterone inhibit fsh & lh At 15 & 16: decreasing estrogen and progesterone is now relieving fsh & lh of inhibition
7. How does the bending of the stereocilia on the hair cells relate to an action potential? What is unusual about receptor potential in hair cells as compared to other sensory receptors?
Bending stereocilia in one direction causes depolarization due to influx of potassium, which is unusual - it's usually sodium influx. The depolarization leads to ap; bending in opposite direction causes repolarization and stops the release
12. What is the role of refraction in vision?
Bends light waves at the cornea and lens, so that the light is focused on the fovea centralis
8. How does the liver contribute to digestion?
Bile salts are also produced by the liver. These salts are essential for fat digestion. The liver also secretes some hco3- which functions in the same manner as the bicarbonate released from the pancreas to neutralize the chyme in the duodenum.
What is meant by cross-bridge activation?
Binding of actin to the myosin cross-bridge
What is the role of calmodulin in smooth muscle contraction?
Binds with calcium to activate myosin light-chain kinase
4. Vein nick name: veins act as ________ reservoir. This means...
Blood (volume) reservoir / veins contain the most blood
1. What function does the lymphatic system play in relation to the cardiovascular system?
Blood plasma leaves the capillaries due to capillary hydrostatic pressure and becomes interstitial fluid. Capillary osmotic pressure and insterstitial hydrostatic pressure are not enough to return all of it back into capillaries, so the remaining fluid enters the lymphatic system which returns it to the cardiovascular system at right and left subclavian veins.
2. What is the major mechanism for long-term regulation of blood pressure?
Blood volume, volume controls pressure and influences venous pressure, venous return, edv, sv and co
12. Would you expect an increased or decreased heart rate in a person with a fever?
Body temperature is an independent determinant of heart rate, causing an increase of approximately 10 beats per minute per degree centigrade. Therefore, the temperature would increase.
2. Compare and contrast coenzyme and cofactor.
Both are enzyme helpers. Certain enzymes must have their helper substances in order to function. Coenzyme: organic ('vitamins') Cofactor : inorganic (like metal ions)
2. Are epsps and ipsps graded potentials or action potentials?
Both epsps and ipsps are graded potentials -signal spreads decrementally away from the synapse by local current
4. Transport maximum refers to the point at which increases in concentration do not result in an increase in movement of a substance across a membrane. Which, facilitated diffusion or active transport, has transport maximum? Or do they both?
Both use transporters, so both types of transport have transport maximums.
1. How does sodium reabsorption differ from water reabsorption?
Both water and na+ are 99% reabsorbed after being filtered from the glomerular capillaries into bowman's space. Sodium reabsorption is an active process occurring in all tubular segments except the descending limb of the loop of henle and the medullary collecting duct. Water reabsorption is by osmosis and is dependent upon sodium reabsorption. Water reabsorption occurs in all tubular segments except the ascending limb of the loop of henle and the distal convoluted tubule.
b. Which pressures in glomerular filtration oppose filtration?
Bowman's space hydrostatic pressure (pbs) Glomerular osmotic pressure (πgc)
3. What other enzymes break down carbohydrates like disaccharides?
Brushborder enzymes of epithelial cells in the small intestine (95% or more digested here).
1. What is the purpose of buffering? Is buffering a means of eliminating additional h+ ions?
Buffering is a means of minimizing changes in hydrogen-ion concentration by combining these ions reversibly with anions such as bicarbonate and intracellular proteins. Buffering doesn't eliminate h+, but it does keep it locked up.
2. Adh secretion is regulated. How?
By inputs from osmoreceptors, and via baroreceptor reflexes
15. If fertilization does happen, the uterine lining must be maintained in order for the embryo to implant into it and continue growing. How does the embryo make sure that the uterine lining is maintained?
By producing hcg (human chorionic gonadotropin) which acts like fsh and lh to maintain corpus luteum, which keeps producing estrogen and progesterone
What is the role of calcium in depolarization of a heart muscle cell?
Calcium is a major player in depolarization along with sodium
4. What sources are available for calcium for the smooth muscle cell?
Calcium released into the cytosol from the sarcoplasmic reticulum and extracellular ca2+ entering the cell through plasma-membrane ca2+ channels
8. Fill in the blanks with the appropriate ion channel type for the sa node action potential. A. Repolarizing phase: l-type _______ channels closing; f-type _______ channels closed; t-type _______ channels closed; _______ channels open
Calcium, sodium, calcium, potassium
1. What is the relationship between co2 and h+ ions?
Carbon dioxide reacts with water to turn into carbonic acid, which releases hydrogen ions
c. Which phase lasts the longer: systole or diastole?
Cardiac cycle = 0.8 sec: 0.3 in systole and 0.5 in diastole (longer)
2. What is the function of the cardiac muscle cells (myocardial cells) and what is the function of the cardiac conducting cells? What percentage of cardiac muscle cells are involved in contraction as opposed to conduction?
Cardiac muscle cells - involved in myocardium contraction Cardiac conducting cells - involved in signal conduction 99% contraction, 1% conduction
8. What variables would the body adjust to compensate for a loss of volume or pressure?
Cardiac output (hr, stroke volume), tpr (vasoconstriction)
4. Where are the peripheral chemoreceptors located? What body fluid do they monitor?
Carotid bodies in carotid arteries and aortic bodies in aortic arch - blood
1. What are the two parts of metabolism?
Catabolism: the breakdown of organic molecules Anabolism: the synthesis of organic molecules
3. Describe the filtrate in terms of cellular and protein content.
Cell- free and protein-free
Which major parts of the brain make up the forebrain?
Cerebrum and dienchephalon
7. List the steps of the renin-angiotensin-aldosterone system.
Chain of events salt depletion (low bp, volume) - increased renin secretion - increased plasma renin concentration - increased plasma angiotensin i concentration due to renin acting on angiotensinogen - increased plasma angiotensin ii concentration due to angiotensin converting enzyme acting on angiotensin i - increased aldosterone release due to angiotensin ii acting on the adrenal cortex - increased plasma aldosterone - increased reabsorption of sodium and some water
5. What molecule is the precursor for all steroid hormones?
Cholesterol
1. What is a cholinergic neuron?
Cholinergic neurons release acetylcholine
5. If a patient's adrenal gland was removed, what would happen to following values? Cortisol levels Acth levels Crh levels
Cortisol levels--> decrease Acth levels--> increase due to negative feedback Crh levels--> increase due to negative feedback
10. Define covalent modulation. (refer back to chapter 3 if you need to.) Is covalent modulation associated with primary active transport?
Covalent bonding of charged chemical groups to some of the protein's side chains alters the charge distribution, and induces a conformational change which increases or decreases affinity. Yes, because atp is involved.
6. What is smooth muscle tone?
Cytosolic ca++ concentration is sufficient to maintain a low level of basal cross bridges = smooth muscle tone
4. Would a decrease or an increase in gfr cause higher plasma levels?
Decrease, fluids remain in the blood instead of being filtered out
3. What are the negative feedback responses at the hypothalamus and anterior pituitary in response to elevated t3 and t4 levels?
Decreased release of trh and tsh
13. A patient has decreased production of thyroid hormone. Would you expect an increased or decreased heart rate in this patient?
Decreased, as thyroid hormone usually increases heart rate
In contrast to skeletal muscle, which ion in smooth muscle is involved in depolarization?
Depolarization in the smooth muscle is the result of ca++ (voltage gated) channels not sodium
2. How is regulation of smooth muscle cross-bridge activation different from skeletal muscle cross-bridge activation? (your answer should go beyond #1)
Difference here... ca++ mediated changes in the thick filaments (myosin) turn on cross-bridge activity in smooth muscle; in striated skeletal muscle ca++ mediates changes in thin filaments (actin) turn on cross-bridge activity.
B. How would the flux of na+ from x to y and the flux of na+ from y to x compare at equilibrium?
Diffusion of na+ from x to y will be equal to the diffusion of na+ from y to x
4. Which hormones secreted by the hypothalamus are excitatory and which are inhibitory?
Dopamine and somatostatin (ss) are inhibitory Crh, trh, ghrh, and gnrh are excitatory
5. Describe the concepts of "dual innervation" and "reciprocal control" in your own words.
Dual innervation: most organs are innervated by both branches Reciprocal control: ↑ activity of one branch; ↓ activity of the other
3. this is figure 17-22 on p.627. a. Why are hormone levels changing?
Due to regulatory effects on each other and due to changes in the follicle (growth, then switching to corpus luteum)
1. Optional: What are the three portions of the small intestine?
Duodenum, jejunum, ileum
2. How does hyperventilation affect po2?
During hyperventilation, your body is taking in an excessive amount of o2 from the atmosphere; therefore, po2 is increased in the blood stream.
3. What affect does hypoventilation have on alveolar pco2?
During hypoventilation, the body is not releasing enough pco2 The result is that the alveolar pco2 rises above the normal value.
3. Optional: what is the role of the diaphragm in ventilation?
During inhalation, the diaphragm contracts, chest expand, lungs are pulled outwards, volume increases and alveolar pressures decreases. During exhalation, the diaphragm relaxes, lungs recoil inward, and volume decreases and alveolar pressure increases forcing air out of the lungs. In simpler terms: during the process of breathing, the diaphragm contracts to add volume to the thoracic cavity, which enables the lungs to make room for more air.
6. What is happening to the diaphragm and intercostal muscles during inspiration?
During inspiration (breathing in), the diaphragm contracts, drawing downward causing an increase in volume in the thoracic cavity. Intercostal muscles contract and act to raise the ribs and elevate the sternum.
Which substance is produced by the kidneys during periods of prolonged fasting?
During long periods of fasting, the kidneys synthesize glucose from amino acids and other precursors and release it into the blood. (gluconeogenesis)
4. Is the composition of the urine static or dynamic? Explain.
Dynamic, concentrations of substances in the filtrate are constantly being adjusted
7. How do the glomerulus afferent and efferent arterioles differ?
Each glomerulus is supplied with blood by the afferent arteriole. The remaining blood not filtered by the bowman's capsule leaves the glomerulus by the efferent arteriole and flows through the peritubular capillaries.
3. Which characteristic of an artery allows its function as a pressure reservoir?
Elasticity
1. Which structural/anatomical component in vessels is common in all types of blood vessels?
Endothelial cells / endothelium / tunic interna
4. Which molecule is filtered then totally reabsorbed under normal circumstances?
Glucose (table 14-2)
4. Which two catecholamines are nearly identical to each other? Where are they produced?
Epinephrine & norepinephrine Adrenal medulla
4. Would you find depolarization with an epsp or an ipsp? What does this term mean?
Epsp - depolarized - brings the membrane potential of the postsynaptic neuron closer to threshold
7. What hormones are produced by the corpus luteum?
Estrogen and progesterone
3. How are osmoreceptors and adh release affected by changes in water concentration?
Excess water lowers body fluid osmolarity, so there is decreased firing by osmoreceptors and decreased adh release. Decreases in body water raises body fluid osmolarity, so there is increased firing of the osmoreceptors and increased adh release.
1. What is the basic function of a capillary?
Exchange of materials between blood and ecf in surrounding organs
3. What causes the latent period/phase of a twitch?
Excitation-contraction coupling (it takes time for electrical signal to convert into contraction and build tension)
2. The pancreas has both exocrine and endocrine functions. Describe those functions.
Exocrine: production of digestive juice including bicarbonate and enzymes into the pancreatic duct into the duodenum; job of the acini (majority of cells) Endocrine: production of insulin (beta cells) and glucagon (alpha cells); job of the islets of langerhans
1. Describe diffusion equilibrium in terms of flux and net flux.
Flux - amount of material crossing a surface in a unit of time Net flux - difference between the two one-way fluxes, always proceeds from higher to lower concentration Diffusion equilibrium - two one-way fluxes are equal in magnitude, but opposite in direction and the net flux is zero
3. What is the role of the ventral respiratory group in ventilation?
Forceful inspiration and forceful (full) expiration
15. How is the absorption of free fatty acids and monoglycerides different from absorption of water-soluble nutrients?
Free fatty acids and monoglycerides enter epithelial (absorptive) cells, then they are enzymatically recombined to form trigliceride. Triglicerides leaves the cells on the basolateral side as chylomicrons, enter lacteal in the intestinal villus. Chylomicrons can't enter blood capillaries like the other small nutrients because they are too big for blood vessel basement membrane. Lymph vessels don't have basement menbrane.
6. Why is the basilar membrane thought of as a frequency-analyzing map?
Frequency-analyzing map • Nearest to the middle ear, the basilar membrane is relatively narrow and stiff; predisposes to easily vibrate in response to high-pitch or high-frequency sounds • The basilar membrane is less wide and less stiff towards far end; predisposes to not easily vibrate, so responses to low-pitch or low-frequency sounds
12. What are the functions of insulin and glucagon? What organ produces them? Which cells?
Functions: insulin decreases blood glucose and glucagon increases blood glucose insulin makes cells take up glucose. Each cell type will process the glucose differently: for example, adipocyte will make fats and muscle cell will make glycogen Islet cells in the pancreas produces both insulin (beta cells of the islet) and glucagon (alpha cells of the islet)
Which neurotransmitter is the major inhibitory nt in the brain?
Gaba
3. What are the two major functions of fsh and lh (for everyone, not males and females separately)?
Gametogenesis Sex hormone stimulation
What types of cell junctions occur between myocardial cells?
Gap junctions
7. Describe the actions of pth in gi tract, bone and the kidneys.
Gi tract - pth stimulates vitamin d conversion into calcitriol, which then acts in the gi tract to increase absorption of calcium from food into blood plasma Bone - pth stimulates osteoclasts to release calcium from bone into blood plasma Kidney - pth stimulates resorption of calcium from the filtrate into blood plasma
a. Which pressure in glomerular filtration favors filtration?
Glomerular capillary hydrostatic pressure (pgc)
5. When insulin communicates to cells (like the ones in #4 above), it makes these cells insert more transport proteins into the plasma membrane. What transport proteins?
Glucose transporter like glut-4
Which neurotransmitter acts as the most excitatory nt in the brain?
Glutamate
3. Which cellular membrane component functions in cell recognition and interaction?
Glycocalyx
1. Liver stores glucose. What molecule is it in?
Glycogen
12. What is happening to the endometrium during the follicular phase? What is happening to the endometrium during the luteal phase?
Growing then maintained
2. How does acid secretion in the stomach contribute to digestion?
H+ starts denaturing food molecules (bolus plus gastric juice is now called chyme). H+ activates pepsinogen (inactive) into pepsin (active; chemical digestion of proteins). In addition, the acidic environment will kill microbes in the food that are susceptible to acidic environments.
5. What cells serve as the sensory receptor in hearing? On what specific structure are these receptors located?
Hair cells - Basilar membrane, inside organ of corti
6. In terms of binding sites, what does the term 50% saturation mean? What does the term 100% saturation mean? With 100% saturation, are there any unbound ligands?
Half the available binding sites occupied by ligand All the available binding sites occupied by ligand With 100% saturation, there may or may not be unbound ligands. % saturation only shows the fraction of receptor proteins that are bound; it does not say aything about unbound ligands.
1. Identify the processes bicarbonate undergoes in the kidneys.
Hco3- is completed filtered in glomerulus; Most reabsorbed in pct, but also some in lh, cortical collecting ducts; Secreted in collecting ducts
1. What is the function of the auditory (eustachian) tube?
Helps to equalize pressure on both sides of eardrum
1. Identify the three major categories of chemical messengers.
Hormones, neurotransmitters, paracrine or autocrine substances
3. When the body needs to increase cardiac output, it increases both heart rate and stroke volume. What about in other instances: does heart rate always change in the same direction (increase or decrease together) as stroke volume?
Hr and sv don't always change in the same direction. E.g. Sv decreases with blood loss and hr increases as a compensatory effect with blood loss.
8. What other substances does the digestive system use for protein digestion?
Hydrochloric acid, pepsin, pancreatic proteases (trypsin, chymotrypsin, carboxypeptidase), and intestinal brushborder enzymes like aminopeptidase
Beginning of the ascending limb of the lh
Hyperoosmotic
d. Bottom of the lh
Hyperoosmotic
6. In the absence of adh, would the urine be hypoosmotic, hyperosmotic or isosmotic as compared to the plasma?
Hypoosmotic
e. Beginning of the dct
Hypoosmotic
5. What is the mechanism of action of a water-soluble messenger?
I. First messenger binds to extracellular receptor causing an activation of intracellular signaling cascades through a second messenger II. Intracellular receptors can activate downstream mediators which affect dna transcription but also have many other effects in the cell
3. What is the mechanism of action of a lipid-soluble messenger? (note: "mechanism of action" means "how does it work".) (hint: comment on the receptor)
I. Ligand enters the cell through diffusion II. Ligand binds to a receptor in the intracellular space (nucleus, cytosol) III. Intracellular receptor/ligand complex acts as transcription factor
1. Describe the four processes of respiration.
I. Pulmonary ventilation (breathing) II. External respiration (movement of o2 from alveoli into plasma; co2 from plasma to alveoli) III. Transport of respiratory gases in the blood IV. Internal respiration (movement of o2 from plasma into cells; co2 from cells into plasma)
3. Renal clearance equals gfr under what circumstance?
If the substanceis filtered but not reabsorbed or secreted
3. What are the effects of vasodilation and vasoconstriction on blood-flow?
If they constrict, blood flow to the tissue dicrease; if they dilate, then blood flow to the tissue increases.
2. What other function(s) does the lymphatic system have?
Immune function (lymphocytes)
4. What is the consequence in terms of visual loss in patients with macular degeneration?
Impairment of the macula densa results in loss of vision in the center of the visual field
4. Where does digestion get completed?
In the small intestine, particularly in the duodenum
5. Where does the majority of absorption occur?
In the small intestine, particularly in the jejunum
12. How is the function of the collecting duct related to the loop countercurrent multiplier system?
In summary, the loop countercurrent system causes the interstitial fluid of the medulla to become concentrated. The resulting hyperosmolarity draws water out of the collecting duct and concentrates the urine.
3. Water reabsorption can increase or decrease dependent on hormonal control. What hormone is involved? Which cells in the kidneys respond to this hormone?
In the collecting ducts, permeability varies d/t physiological control of the hormone vasopressin (antidiuretic hormone (adh)). Adh stimulates insertion of aquaporin water channels into the luminal membrane. Once the aquaporins are in place, h2o moves down its concentration gradient through tubular cells. In other words, water moves through osmosis.
2. Where would you find oxygen in an erythrocyte?
In the cytoplasm and attached to the hemoglobin
2. Define vasoconstriction and vasodilation. In your answer, you should use the term "intrinsic tone".
Increase of contractile force above intrinsic tone of smooth muscles that surround arterioles = vasoconstriction = decrease diameter Decrease of contractile force below tone = vasodilation = increased diameter
10. What effect would an increase in map have on bulk flow?
Increased capillary hydrostatic pressure --> increased filtration
7. What would be the effect of increasing capillary hydrostatic pressure?
Increased filtration, protein-free fluid is lost from plasma and enters interstitial fluid
4. What is the relationship between hematocrit and blood viscosity?
Increased hematocrit = increased blood viscosity
12. What is the relationship between plasma volume and gfr?
Increased plasma volume = increased gfr; decreased plasma volume = decreased gfr
10. What would happen to stroke volume if sympathetic neural input to the veins was increased?
Increased sns would increase edv, so based on the frank starling mechanism stroke volume would increase
7. How does epinephrine affect heart rate?
Increases
3. According to table 6-11, what are the effects of the sympathetic nervous system on the heart? What receptors types are involved?
Increases hr, contractility, and conduction velocity;
3. What role do the kidneys have in blood pressure regulation?
Increases in arterial pressure (increased co) induces a decrease in volume through excretion of water through the kidneys to restore the bp. Increases in blood volume (increased ingestion or retention) leads to an increase in arterial pressure which induces the kidneys to decrease volume through the excretion of water. The opposite would be true in cases of decreased blood pressure.
6. Is acetylcholine inhibitory or excitatory in the atria?
Inhibitory --> decreases heart rate
7. How do the stimuli for membrane activation in smooth muscle differ from that of skeletal muscle?
Inputs influencing contraction in smooth muscle include spontaneous electrical activity, neurotransmitters, hormones, local changes and stretch. Skeletal muscle contraction is dependent on acetylcholine binding to acetylcholine receptors on the muscle plasma membrane.
6. How do peripheral and integral proteins differ?
Integral membrane proteins are closely associated with the membrane lipids. They cannot be extracted from the membrane without disrupting the lipid bilayer. They are ampipathic. Peripheral membrane proteins do not associate with the nonpolar regions of the lipids in the interior of the membrane. They are not amphipathic.
7. Describe "transmembrane protein".
Integral proteins spanning the entire membrane
2. For each class of neurons, answer the following questions. D. Most neurons belong to ... which class?
Interneurons; signal integration is an essential part of the nervous system
9. The intrapleural pressure has to be (negative, positive, or zero) for proper lung function?
Intrapleural pressure must always be less than or more negative than alveolar and atmospheric pressures.
3. Would you find hyperpolarization with an epsp or an ipsp? What does this term mean?
Ipsp - hyperpolarized - drives the membrane potential of the postsynaptic neuron farther away from threshold
6. "muscle contraction means it's getting shorter in length" is a false statement. Why is it false?
Isometric contraction is possible (e.g. holding dumbbell in place) See fig 9.19 & 9.20
a. Bowman's space: the fluid in bowman's space is __________ to plasma.
Isoosmotic
c. Beginning of the descending limb of the lh
Isoosmotic
f. Cortical collecting duct
Isoosmotic
g. Beginning of medullary collecting duct
Isoosmotic
b. Pct
Isosmotic
c. When are the av valves closed?
Isovolumetric contraction, ventricular ejection, isovolumetric relaxation
7. What role does acetylcholinesterase play at the nmj?
It breaks down the acetylcholine and allows the signal to stop ("cessation of signal")
8. Angiotensin ii increases blood pressure through an increase in tpr. How does angiotensin ii increase tpr?
It causes arteriolar vasoconstriction which increases tpr.
2. How is pth similar to aldosterone?
It controls two different variables in opposite ways
13. Define emulsification.
It is the breakdown of large fat globules into smaller, uniformly distributed particles, not chemical digestion. Emulsification is the first preparation of fat for chemical digestion by specific enzymes (lipases).
2. How is cardiac output calculated?
It is the product of heart rate (hr) and stroke volume (sv) (co=hr x sv). Hr is measured as number of beats per minute, while sv is measured as the amount of blood ejected by each ventricle with each beat. E.g. 72 beats/min x 0.07 l (70 ml)/beat = 5.0 l/min
8. What exactly is a muscle contraction?
It simply refers to activation of the force-generating sites within muscle fibers—the cross-bridges. It does not necessarily mean that the muscle has "shortened." For example, holding a dumbbell at a constant position requires muscle contraction, but not muscle shortening.
Which organ system is the main system in terms of h+ ion regulation?
Kidneys
3. What is the kidneys role in waste management?
Kidneys excrete metabolic waste products into the urine as fast as they are produced. This keeps waste products, which can be toxic, from accumulating in the body.
5. What is the direct cause of ovulation?
LH surge
3. What is the function of a lacteal?
Lacteals serve to absorb products of digested fat and to recirculate these products back into the venous circulation.
2. Under normal circumstances, would t3 and t4 be released without a signal from tsh?
No
4. The best diffusion scenario is to have small molecule diffusing through a large surface area through water at a high temperature. Now alter the specifications to decrease diffusion. Now alter the specifications increase diffusion.
Larger molecule would decrease diffusion Increasing temperature would increase diffusion
4. How do the larger radii of arteries affect the resistance to blood flow in arteries?
Larger radius lead to low resistance
7. "hyperextended muscle can generate a larger tension because it starts out longer" is a false statement. Why is it false?
Largetst tension is generated when the muscle fiber starts out at an optimal length, not when it had been stretched or hyperextended. This is because most tension is generated when thick and thin filaments start out with enough overlap to make many cross-bridges right away See fig 9.21
21. Which parts of the eye are related to astigmatism? How would astigmatism affect refraction?
Lens or cornea surface is not smooth; can be corrected with eyeglasses or contact lenses The light would be refracting in many directions due to the different surface heights on the lens or cornea. Hence, the light would not focus on the fovea centralis.
A. At equilibrium in compartment x, will the na+ be more than, less than or the same as its original concentration?
Less, because sodium has diffused down its concentration gradient into compartment y
7. What would happen to anterior pituitary hormone levels if you blocked the hypothalmo-pituitary portal veins? What would happen to posterior pituitary hormone levels if you blocked the hypothalmo-pituitary portal veins?
Levels of anterior pituitary hormones would decrease except for prolactin. Prolactin would increase as dopamine would not be able to inhibit its release. Posterior pituitary is not affected, as it does not require blood for communication from the hypothalamus
8. What type of cells do lh and fsh act on respectively?
Lh on theca cells (outer layer of follicle) Fsh on the granulosa cells (immediately surrounding the ovum)
14. What is the function of lipase in fat digestion?
Lipase from the pancreas digests fat at the surface of the emulsion droplets. The enzyme splits the bond between the fatty acid and glycerol. Resulting in the release of two free fatty acids and one monoglyceride from one triglyceride. These byproducts either diffuse across the luminal membranes of epithelial cells or form micelles with bile salts until the cells need the byproducts.
7. Hormone transport in blood: which hormones need to be protein-bound? Why?
Lipid-soluble, because they don't mix well with water of the blood plasma
3. this is figure 17-22 on p.627. c. Describe the switch from negative feedback to positive feedback then to negative feedback, from the ovaries to the anterior pituitary.
Low estrogen + inhibin --> negative feedback (primarily fsh) High estrogen --> positive feedback Estrogen + progesterone --> negative feedback
11. In a healthy person, how does the body respond if sodium levels fall? (hint: aldosterone)
Low salt - more aldosterone; high salt - less aldosterone
6. In a healthy person, how does the level of salt correlate with the amount of renin released?
Low salt - more renin; high salt - less renin
1. A decrease in total body sodium is correlated with (choose one: high or low) plasma volume?
Low total body sodium correlates with low plasma volume
1. An enzyme is said to be a catalyst. What does an enzyme do to catalyze reactions?
Lowers activation energy to make biological reactions proceed at a higher reaction rate
4. Describe the multiple steps of how oxygen moves from the alveolar spaces to the hemoglobin in erythrocytes.
Lungs • Alveolar po2>plasma po2 • O2 diffuses into plasma • ↑ plasma po2 • O2 diffuses into rbcs • ↑ o2 in rbcs • ↑ oxyhemoglobin
4. What sex chromosomes do males have? Females?
Male: xy female: xx
How is map calculated?
Map = diastolic pressure plus 1/3 of the pulse pressure [map = dp + 1/3 (sp-dp)]
6. How do systolic blood pressure and diastolic blood pressure relate to arterial pressure and ventricular ejection?
Maximum arterial pressure reached during peak ventricular ejection = systolic pressure Arterial pressure before ventricular ejection begins = diastolic pressure
1. Optional: what are the digestive functions of the mouth?
Mechanical digestion by teeth and tongue; Early chemical digestion by salivary amylase; Preparing food by moistening it with saliva (turns it into bolus)
1. What is mediated transport?
Mediated transport is the movement of the molecules through transporters. A change in the conformation of the transporter exposes the transporter binding site first to one surface of the membrane and then to the other.
5. Where are the central chemoreceptors located? What body fluid do they monitor?
Medulla - brain ecf
1. Describe the metabolic actions of thyroid hormones.
Metabolic actions (t3 and t4) •Maintain a high energy state O Stimulate carbohydrate absorption from the small intestine O Increase fatty acid release from adipocytes O Stimulate activity of na+/k+-atpases Atp is utilized Glycolysis is stimulated to produce more atp Heat is produced (significant portion of total heat produced each day)
l. When is ventricular pressure at a maximum?
Midway through ejection
3. What would happen to the rmp in the absence of atp?
More sodium would enter the cell due to its concentration gradient and electrical gradient. This would render the interior of the cell more positive than negative. The resting membrane potential would also become more positive.
5. Into what structure does the venous blood from the heart muscle drain?
Most of the cardiac veins drain into a single large vein, the coronary sinus. The coronary sinus empties into the right atrium.
6. Optional: what happens to plasma proteins during glomerular filtration?
Most plasma proteins are excluded almost entirely from the filtrate because of their size and charge. (in other words, they remain in the blood plasma)
4. How does hypoventilation affect po2?
The body is not taking in enough oxygen during hypoventilation Po2 decreases below the normal value.
1. Describe the difference between a muscle fiber and a myofibril.
Muscle fiber is a single skeletal muscle cell. They are multinucleated and have many mitochondria. Muscle fibers are filled with cytoplasm (sarcoplasm) and myofibrils. The plasma membrane is called the sarcolemma and the smooth endoplasmic reticulum is called the sarcoplasmic reticulum. Myofibril: smaller, cylindrical bundles of thin and thick filaments within the muscle fiber
2. Optional: what is the technical definition of a "twitch"?
Muscle response to a single action potential
4. What three major tissues does insulin affect? Summarize what insulin does to each of the tissue type.
Muscle: insulin makes muscle fibers take up glucose and store it as glycogen, take up amino acids and make more protein Adipocytes (fat tissue): insulin makes adipocytes take up glucose and make more triglycerides Liver: insulin makes hepatocytes take up glucose and store it as glycogen, stop making glucose, and make more triglycerides
Which contractile filaments are found in cardiac muscle?
Myosin and actin
2. What is the effect of aldosterone on potassium reabsorption, secretion and excretion?
No effect on reabsorption Increases secretion Increases excretion
3. Compare the effect of aldosterone on na+ and k+ reabsorption and excretion.
Na+ - increased reabsorption, decreased excretion K+ - no effect on reabsorption, increased excretion due to increased secretion
23. Compare and contrast myopia (nearsightedness) and hyperopia (farsightedness) in terms of eye anatomy, ability to see distant or near objects, image position in reference to the retina, and correction. (nearsightedness)
Nearsightedness • Eye anatomy-eyeball too long • Can't see far objects clearly; can see near objects clearly • Image falls in front of the retina • Correction - concave lens
3. How do feedback systems contribute to homeostasis?
Negative feedback systems work to return physiological states back to set point and thereby maintain homeostasis.
1. Define osmosis.
Net diffusion of water across a membrane from higher to lower concentration
5. How do you determine net glomerular filtration pressure?
Net glomerular filtration pressure = pgc - pbs - πgc
5. Optional: which type of cholinergic receptor is found at the nmj? Refer back to figure 6.46.
Nicotinic acetylcholine receptor, which are ligand-gated ion-channel
10. Does the parasympathetic nervous system affect ventricular contractility?
No
7. If a drug (ligand) has achieved 100% saturation, does it benefit the patient to give more of the drug? Explain.
No, additional drug would not be able to bind and would be free in the plasma; additional free drug can lead to toxicity
9. Can the mean arterial pressure (map) be determined by taking the average of the systolic and diastolic blood pressure? Why or why not?
No, because diastole lasts longer than systole. The system spends twice as long in diastole as it does in systole, so diastolic pressure counts for twice as much for the map
6. Optional: can cerebellar and cerebral be used interchangeably? Why or why not?
No, because the cerebrum is a part of the forebrain and the cerebellum is a part of the hindbrain.
5. Does atp have a role in facilitated diffusion?
No, facilitated diffusion is passive transport.
8. Is the ecm the same throughout the body?
No, is the material between the bone cells the same as the material between the cells in loose connective tissue
8. Is epinephrine released from the sympathetic nervous system directly?
No, it is released from the adrenal medulla
3. Does the blood volume that was pumped from the right side of the heart into the lungs differ from the blood volume reentering the left side of the heart from the lungs?
No, it should be the same in a healthy person
8. Do all muscle types require extracellular calcium to produce a contraction? In this regard, cardiac muscle is more like... skeletal muscle or smooth muscle?
No, only smooth and cardiac muscle
13. Is the degree (amount) of refraction constant in vision?
No, the cornea doesn't change shape, but the shape of the lens is altered for near and far vision
14. Bulk flow is the basis of filtration. Is bulk flow involved in reabsorption? Explain.
No, there is no bulk flow in reabsorption; reabsorption and secretion occur molecule-specific through transport proteins
6. Are there any inhibitory neuromuscular junctions?
No, they are all excitatory
10. What role do non-fibrous proteins play in the ecm?
Non-fibrous proteins - act as adhesion and recognition molecules (communication), as well as filler (like cement) between the supporting collagen
e. Which valves are open during isometric ventricular contraction?
None
f. Which valves are open during isometric ventricular relaxation?
None
k. Which valves are open during ventricular relaxation?
None during the isovolumetric period; atrioventricular valves - tricuspid and bicuspid during filling
Describe the relationship be between the glomerular capillary blood pressure and the other pressures involved in glomerular filtration in order for filtration to occur.
Normally, the net filtration pressure is always positive because the glomerular capillary hydrostatic pressure (pgc) is larger than the sum of the hydrostatic pressure in the bowman's space (pbs) and the osmotic force opposing filtration (πgc)
4. Which cell in the cns is involved in myelin production? Explain the cell the axon relationship.
Oligodendrocytes; branch to form myelin on as many as 40 axons
9. Second messenger cascades produce amplified responses upon receptor activation by one ligand. Why would this be beneficial?
One ligand producing multiple responses is a very energy efficient process for the cell
1. How is oogenesis different from spermatogenesis?
Oogenesis begins before birth Oogenesis pauses between birth and puberty Oogenesis produces one large, nutrient-rich gamete (ovum) instead of four small, motile gamete (sperm)
2. Optional: study figure 17.1 on p.604. What are the main differences between gametogenesis in the testes versus in the ovaries?
Oogenesis results in only one gamete but spermatogenesis is the more typical meiosis resulting in four gametes
1. By what mechanism do the valves of the heart open and close?
Opening and closing of valves are passive processes resulting from pressure differences across the valves. This ensures a one-way flow.
10. What protein in rods and cones actually responds to light?
Opsin (rhodopsin in rods)
8. What bone cells are responsible for bone resorption? What effect does this have on plasm calcium concentration?
Osteoclasts; increase plasma calcium
3. this is figure 17-22 on p.627. b. What happens in the ovary as a result of these changing hormones? What happens in the uterus as a result of these changing hormones?
Ovary: as fsh increase, follicle grows and produces more estrogen More estrogen stimulates a spike (big sudden increase) in lh Estrogen and progesterone from corpus luteum inhibit fsh and lh (negative feedback) which then cause corpus luteum degradation uterus: endometrium starts to build up due to estrogen endometrium is maintained due to estrogen and progesterone
1. How is oxygen carried in the blood?
Oxygen is carried in the blood in two forms: dissolved and bound to hemoglobin.
5. Give examples of molecules that diffuse easily through the cell membrane.
Oxygen, carbon dioxide, fatty acids, and steroid hormones are examples of nonpolar molecules that diffuse rapidly through the lipid portions of membranes. Remember that lipophilic (lipid-loving) substances move through easily. Small uncharged polar will diffuse.
16. Define positive feedback in your own words (refer back to ch1 if necessary). Describe how positive feedback operates for parturition (birthing).
Parturition: oxytocin stimulates and is stimulated by uterine contraction
16. What type of transport is needed to absorb free fatty acids?
Passive transport as they use diffusion to cross the membrane.
8. Fill in the blanks with the appropriate ion channel type for the sa node action potential. C. Slow depolarization to threshold: _______ channels closing; f-type _______ channels open; t-type _______ channels open
Potassium, sodium, calcium
6. Name and describe (in terms of filtration or reabsorption) the four forces involved in bulk flow.
Pc - capillary hydrostatic pressure - move fluid out of the capillary = filtration (+) Pi or pif - interstitial hydrostatic pressure - move fluid into the plasma = absorption or reabsorption (-) Πc - capillary osmotic (oncotic) pressure - move fluid into the plasma through an osmotic force due to plasma protein concentration = absorption or reabsorption (-) Πif - interstitial osmotic (oncotic) pressure - move fluid out of the capillary through an osmotic force due to interstitial protein concentration = filtration (+)
3. What is hematocrit?
Percentage of blood occupied by rbcs
21. What is ejection fraction? How do you calculate ejection fraction?
Percentage of edv ejected with each contraction Ef = sv/edv; percentage defined as the ratio of stroke volume (sv) to end-diastolic volume (edv)
Case 2: a 21-year old college student is admitted to the hospital with a two day history of vomiting. The vomiting began shortly after he ate chinese food that was more than a week old. The following blood measurements are obtained: Ph = 7.48 Pco2 = 44 mmhg Hco3 = 40 meq/l
Ph - high (alkaline), co2 - normal, hco3 - high (alkaline) = metabolic alkalosis
2. Identify the primary acid-base disorder in the cases below. Also identify the body's response (metabolic or respiratory). Case 1: a 53-year-old man with chronic obstructive lung disease is admitted to the hospital with pneumonia. The following blood measurements are obtained: Ph = 7.30 Pco2 = 55 mmhg Hco3 = 29 meq/l
Ph - low (acidic), co2 - high (acidic), hco3 - normal = respiratory acidosis
2. Which type of chemical is the major chemical component in the cellular membrane?
Phospholipids
7. Describe how information moves through the three layers of the retina.
Photoreceptor, bipolar, ganglion neuron Light signals are converted into electrical signal by opening and closing of ion channels in photoreceptors. Photoreceptor and bipolar cells only undergo graded potentials, as they lack the voltage-gated channels that mediate action potentials in other types of neurons. Ganglion cells are the first cells in the pathway where action potentials can be initiated.
2. Describe the sensitivity of the photoreceptors.
Photoreceptors are receptors sensitive only to the visible spectrum of light measured in wavelengths Rods: no color & cones: color sensitive
6. What controls the secretion of parathyroid hormone, and what are the major effects of this hormone?
Plasma calcium ion concentration regulates parathyroid cell secretion of pth Major effects: increase plasma calcium
6. What is the role of the podocytes?
Podocytes are specialized cells that play an integral role in the renal glomerular filtration barrier via their foot processes.
6. Give examples of molecules that do not diffuse easily through the cell membrane.
Polar molecules and hydrophilic (water-loving) molecules do not diffuse readily through the membranes.
2. Describe the sequence of events from the activation of the pontine ("in the pons") control centers to ventilation.
Pons send action potentials to the dorsal respiratory group (drg) to stimulate the neurons. Drg neurons stimulate spinal motor neurons innervating the diaphragm and intercostal muscles. Phrenic nerve stimulates diaphragm and other spinal nerves stimulate intercostal muscles, and they all contract. Contraction of these muscles enlarges the chest cavity volume and results in inspiration/inhalation.
5. There are no t-tubules in smooth muscle cells. How does the design of the smooth muscle cell make up for this?
Portions of the sarcoplasmic reticulum are located near the cell membrane, so an action potential in the plasma membrane can trigger release of ca++. 2nd messenger systems can also trigger ca++ release. It's also much smaller and shorter than the skeletal muscle fiber.
2. How is the posterior pituitary gland different from the anterior pituitary gland in terms of attachment to the hypothalamus?
Posterior pituitary gland is attached by the axons of the neurosecretory cells from the hypothalamus; whereas anterior pituitary gland is 'attached' or connected by the hypothalamo-pituitary portal vessels in the infundibulum
1. How are the posterior pituitary hormones different from the anterior pituitary hormones in terms of site of synthesis?
Posterior pituitary hormones are synthesized by the hypothalamus; whereas anterior pituitary hormones are synthesized in the anterior pituitary. Posterior pituitary hormones are released via a neural signal from the hypothalamus; whereas, anterior pituitary hormones are released through a hormonal signal from the hypothalamus.
1. How do potassium and sodium levels affect the secretion of aldosterone at the level of the adrenal cortex?
Potassium - elevated k+ levels directly stimulate the adrenal cortex to release aldosterone. Sodium - elevated na+ levels indirectly stimulate the adrenal cortex to release aldosterone.
2. What are the functions of granulosa cells in the follicular phase?
Secrete estrogen Support egg development
8. Fill in the blanks with the appropriate ion channel type for the sa node action potential. B. Depolarization at threshold: _______ channels closing; f-type _______ channels closing; t-type _______ channels closing; l-type _______ channels open
Potassium, sodium, calcium, calcium
19. How does presbyopia relate to changes in accommodation? Be specific.
Presbyopia is a condition related to age related changes in accommodation for near vision; elasticity in the lens is decreased
4. What factor is responsible for the opening and closing of the heart valves?
Pressure differences between the atria and ventricles, and between the ventricles and aorta and pulmonary trunk For example, when atrial pressure is higher than ventricular pressure, the av valves open.
1. What is the relationship between pressure, resistance and flow? This relationship is expressed in an equation. Explain what the equation means.
Pressure is the force exerted on the vessel wall measured in mm hg (millimeters of mercury) Flow is the volume moved per time measured in ml/min (milliliters per minute) Resistance is the measure of the friction that impedes flow. It is a measure of how difficult it is for blood to flow between two points at any given pressure difference F=∆P/R If the pressure difference changes independent of resistance, the flow will change in the same direction as the pressure difference; for example, if the pressure difference increases, flow will increase If the resistance changes independent of the pressure difference, the flow will change in the opposite direction as the resistance; for example, if the resistance increases, flow will decrease
2. Artery nick name: arteries act as ________ reservoir. This means...
Pressure reservoir / arteries maintain high enough blood pressure for the cardiovascular system
14. What is meant by accommodation?
Process through which the eye focuses between near and far objects
2. Describe the role of leydig cells.
Produce testosterone
13. Optional: how does progesterone affect the cervical mucus? How does this affect sperm in the female reproductive tract?
Progesterone thickens cervical mucus (to protect growing baby) and slows the sperm down
11. Optional: describe how a hormonal contraceptive containing progesterone prevents pregnancy.
Prolongs luteal phase and does not allow growth of a new follicle
3. Is it possible for more than one type of ligand to bind to a binding site? Explain.
Proteins may contain many binding sites that are specific for different ligands or multiple sites for the same ligand or in some cases can bind a number of related ligands (portion of ligand is complementary to binding site).
1. The blood plasma is the ecf of blood cells. Blood plasma is mostly water but also contains some important molecules, like glucose and carbon dioxide and proteins. What are the function of the various plasma proteins? Immunoglobulin, Fibrinogen, Albumin
Proteins- Immunoglobulin: antibody, helps your body fight invading organisms Fibrinogen: precursor to fibrin, used for blood clotting in case of injury Albumin: osmotic protein, maintains blood osmolarity and allows fluid return to capillaries
4. What is the role of cholesterol in the cell membrane?
Provides rigidity, and is integral in the formation of vesicles (receptor mediated endocytosis)
2. Where does the majority of sodium and water reabsorption take place?
Proximal convoluted tubule
Where does sodium reabsorption occur in the nephron tubules?
Proximal convoluted tubule, ascending limb of the lh, distal convoluted tubule, cortical collecting duct
Where does water reabsorption occur in the nephron tubules?
Proximal convoluted tubule, descending limb of the lh, cortical collecting duct, Medullary collecting duct
1. What hormone is the main regulator of calcium and phosphate levels in the body?
Pth (parathyroid hormone)
What is pulse pressure?
Pulse pressure is the numerical difference between systolic pressure and diastolic pressure. It can be felt as a pulsation or throb in the arteries of the wrist or neck with each heartbeat.
2. How would you calculate renal clearance?
Rc=u x v/p • U=concentration of the substance in the urine (mg/ml) • V=flow rate of urine formation (ml/min) • P=concentration of substance in the plasma (mg/ml)
In which structure does reabsorption begin?
Reabsorption begins in the proximal convoluted tubules
13. Where does reabsorption happen in the nephron? Be specific.
Reabsorption begins in the proximal convoluted tubules and continues in the loop of henle, distal convoluted tubules, and collecting tubules; there is no reabsorption in the bowman's space
5. As stated in #4, receptor potentials are graded potentials. But receptor potentials can lead the sensory neuron to generate action potentials. How do receptor potentials cause action potentials generated by/within the sensory neuron?
Receptor potentials must reach threshold potential in order to elicit an action potential.
4. What effect does testosterone have on the anterior pituitary gland?
Reduce lh production (negative feedback)
9. How does the length of the refractory period in a cardiac muscle cell relate to tetany?
Refractory period in cardiac muscle cell lasts almost as long as the action potential, so the cell has to relax before it experiences another acion potential. Thus, it prevents tetany by design.
1. What is the role of the dorsal respiratory group in ventilation?
Regulate inspiration
1. Identify the functions of the plasma membrane.
Regulates passage in and out of the cell • Acts as selective barrier • Detects chemical cellular messages (cellular communication) • Anchors cells to adjacent cells and to the ecm of ct proteins, and allows cells to interact to form tissues
16. Which relationship is demonstrated through the frank-starling mechanism?
Relationship between end-diastolic volume and stroke volume
6. Put the following in the appropriate hypothalamic-anterior pituitary relationships. • Gnrh, ghrh, ss, trh, da, crh, gh, fsh, tsh, lh, prolactin, acth
Secretion of acth is stimulated by crh Secretion of gh is stimulated by ghrh Secretion of gh is inhibited by ss Secretion of prolactin is inhibited by da Secretion of tsh is stimulated by trh Secretion of lh and fsh is stimulated by gnrh
22. What is "afterload"? What effect does it have on stroke volume?
Resistance to blood ejection exerted by arterial pressure Afterload results in decreased stroke volume
4. Define the terms respiratory acidosis and respiratory alkalosis in terms of co2 concentration.
Respiratory acidosis: high h+ concentration due to hypoventilation Respiratory alkalosis: low h+ concentration due to hyperventilation
1. How is the conducting zone different from the respiratory zone? Is the conducting zone same as "upper" respiratory tract, and is the respiratory zone the same as "lower" respiratory tract?
Respiratory zone (gas exchange) Conducting zone (air conduction) No - lower respiratory tract is divided into conducting and respiratory zones
7. Describe the flow of blood from the right atrium back to the right atrium of the heart.
Right atrium --> tricuspid av valve --> right ventricle --> pulmonary sl valve --> pulmonary trunk and arteries --> pulmonary capillaries --> pulmonary venules and veins --> left atrium --> bicuspid (mitral) av valve --> left ventricle --> aortic sl valve --> aorta --> systemic arteries --> systemic arterioles --> systemic capillaries --> systemic venules --> systemic veins --> (superior or inferior) vena cava --> right atrium
1. Define and describe the resting membrane potential (rmp) in your own words.
Rmp is the electrical potential between the outside and inside (inside relative to outside) of the cell. This value will hold steady in the absence of changes in electrical current. Rmp exists because of tiny excess of negative ions in the cell.
6. How would you differentiate a cone from a rod in terms of quantity, location on the retina and function?
Rods • Higher quantity when compared to cones (120 million) • Located on the periphery of the retina, absent from fovea centralis (central fovea) • Specialized for vision in dim light O Discriminate between different shades of gray (no color vision) O Recognize shapes and movement Cones • Lesser quantity when compared to cones (6 million) • Highly concentrated in the central fovea • Specialized for color vision O High visual acuity in bright light
2. Place the following in order of conduction and identify the location of each: purkinje fibers, sa node, r and l bundle branches, av node and bundle of his.
Sa node (right atrium) --> av node (interatrial septum) --> bundle of his (between atria and ventricles in the septum) --> r & l bundle branches (interventricular septum) --> purkinje fibers (walls of the ventricles)
3. All cells in the conducting system also have pacemaker potential and are thus autorhythmic. Then why is the sa node considered to be the pacemaker?
Sa node has the fastest pacemaker rate. The other cells have lower inherent pacemaker rates; so the sa node usually overrides them (i.e. Creates an action potential before the other ones do.)
5. Which cell in the pns is involved in myelin production? Explain the cell the axon relationship.
Schwann cells; form individual myelin sheets on portions of axons (many schwann cells to one axon)
2. Iodide ion needs to be transported into the follicle cell. How is this achieved?
Secondary active transport: sodium concentration gradient is used to bring iodide into the cell (sodium concentration is made low inside the cell, so that sodium will go down its concentration gradient into the cell. A symporter lets sodium down its gradient while pulling iodide against its gradient, both into the cell.
2. What determines if a ligand will bind with a receptor protein?
Shape or conformation (they have to fit) (charge attraction also important)
10. Optional: through which type of transport are most small peptides absorbed?
Short chains of two or three amino acids are also absorbed by a secondary active transport coupled to the hydrogen ion gradient.
3. How is total peripheral resistance related to total arteriolar resistance?
Since arterioles are the major determinants of total peripheral resistance, so you could say that tpr is total areteriolar resistance.
6. How does the effect of excitatory and inhibitory nervous stimulation differ in skeletal, smooth, and cardiac muscle?
Skeletal is only excitatory, but cardiac and smooth can be excitatory or inhibitory
6. What is the role of the muscles in venous blood flow?
Skeletal muscle pump and respiratory pump cause increased venous pressure and venous return - forces more blood back to the heart
8. What are the three types of skeletal muscle fibers, and how are they different from each other?
Slow oxidative (type i) ---Red in color (myoglobin and blood vessels) ---Lots of mitochondria ---Uses oxygen in aerobic metabolism ---Produces prolonged, sustained contractions Fast oxidative-glycolytic (type iia) ---Uses both aerobic and anaerobic metabolism ---Rapid contraction, but intermediate properties Fast glycolytic (type iib) ---White in color (low myoglobin and blood vessels) ---Anaerobic metabolism ---Rapid contraction
2. How does a specific pathway compare to a non-specific pathway?
Specific (single-type of stimulus) and nonspecific pathways (several different types of signals) to transmit information
7. How does sympathetic neural input affect the smooth muscle in the veins?
Sns contracts smooth muscle causing a decrease in diameter (constriction)
10. Why is it important that the vasa recta has a countercurrent anatomy?
So the high salt concentration doesn't get washed away into the blood but remains in the interstitial fluid, to let the medullary collecting duct aquaporins to do their work.
5. Both sodium and potassium act as stimuli for feedback mechanisms during an action potential. Which type of feedback to sodium and potassium trigger?
Sodium - positive feedback during depolarization Potassium - negative feedback during repolarization
2. Draw a line for the solute x concentration on the graph below. Try to draw it yourself and then check it against figure 4-23 in the book. You should also state the process in writing. You should understand how the solute concentration changes as it moves from lumen to epithelial cell, and then from epithelial cell to plasma. You should be able to integrate the following terms in your explanation: interstitial, intracellular, plasma, apical, basolateral, active transport, passive transport, concentration gradient and the other terms illustrated in the picture.
Sodium enters the apical side of the epithelial cell through a cotransporter. As a result of the sodium movement, there is a change in the electrochemical gradient. The energy generated from the change in the electrochemical gradient is enough to move the solute from low to high concentration. This is an example of secondary active transport. The solute moved from low to high concentration from the lumen to the intracellular space. Its movement from the intracellular space to the interstitial space on the basolateral side will therefore be from high to low concentration. The picture shows a transporter on the basolateral side of the cell. This is an example of passive transport through a membrane protein (transporter). Another name for this process is facilitated diffusion. No energy is required on the basolateral side of the cell. Once the solute moves into the interstitial space, it will easily travel across the capillary membrane into the plasma.
1. Draw a line for the sodium concentration on the graph below. Try to draw it yourself and then check it against figure 4-22 in the book. You should also state the process in writing. You should understand how the sodium concentration changes as it moves from lumen to epithelial cell, and then from epithelial cell to plasma. You should be able to integrate the following terms in your explanation: interstitial, intracellular, plasma, apical, basolateral, active transport, passive transport, concentration gradient and the other terms illustrated in the picture.
Sodium enters the apical side of the epithelial cell through an ion channel. This is a passive transport process. The sodium is moving down its concentration gradient from the lumen to the intracellular fluid. Sodium exits the cell on the basolateral side through a sodium-potassium pump. The concentration of sodium is greater in the interstitial space than in the intracellular space. The sodium must move from low to high concentration. In other words, sodium must move against the concentration gradient. In addition, the picture shows atp as an integral part of the sodium-potassium pump. The use of atp and the movement of na+ against the concentration gradient demonstrate an active transport process. Once the sodium moves into the interstitial space, it will easily travel across the capillary membrane into the plasma.
7. Complete the following for cardiac muscle action potential with the appropriate ion channel type. In other words, each blank should have one of the following ions: na+, k+, ca2+ C. Repolarization: _______ channels closed; l-type_______ channels closing; ________ channels open
Sodium, calcium, potassium
7. Complete the following for cardiac muscle action potential with the appropriate ion channel type. In other words, each blank should have one of the following ions: na+, k+, ca2+ A. Depolarizing phase: _______ channels open; _______ channels closing; _______ channels closed
Sodium, potassium, calcium
7. Complete the following for cardiac muscle action potential with the appropriate ion channel type. In other words, each blank should have one of the following ions: na+, k+, ca2+ B. Continued depolarization: _______ channels closed; _______ channels closed; l-type ________ channels open
Sodium, potassium, calcium
1. Which branch of the pns innervates skeletal muscle?
Somatic motor
1. Optional: afferent pathway carry sensory information. Where is the sensory information being carried to?
Somatosensory cortex in the cns
1. All spinal nerves are mixed nerves. What does this mean?
Spinal nerves have both sensory and motor fibers, or to put it another way, spinal nerves have both efferent and afferent fibers.
6. Optional: what is the sry gene and where is it found?
Sry (sex-determining region on y) on the y chromosome starts male development cell differentiation program
b. What is meant by the term isovolumetric?
Stays at the same volume
1. Describe the role of sertoli cells.
Stimulate spermatogenesis ('nurse' the growing sperm) Produce inhibin as a negative feedback signal to the fsh-producing cells of the anterior pituitary
3. What effect does fsh have on the testes?
Stimulate testes for spermatogenesis
12. How does surfactant contribute to surface tension, compliance and expansion of the lungs?
Surfactant reduces the cohesive forces between water molecules on the alveolar surface. Therefore, surfactant lowers the surface tension, which increases lung compliance and makes it easier to expand the lungs.
15. How do you calculate stroke volume? Use the volumes given in this graph to calculate the stroke volume of this patient.
Sv (l) = edv (l) - esv (l) = 135 - 65 = 70ml
4. What effect does neural input have on spontaneous depolarization at the sa node?
Sympathetic - decreases time of depolarization to threshold (get there faster), so hr increases Parasympathetic - increases time of depolarization to threshold (get there slower), so hr decreases
5. What effect does the autonomic nervous system have on the slope of the pacemaker potential?
Sympathetic - increased slope (more steep-will reach threshold faster than normal) due to increased permeability to na+ (f-type channels) Parasympathetic - decreased slope (less steep-will reach threshold slower than normal) due to increased permeability to k+
3. Compare co2 movements in and out of blood in the systemic and pulmonary capillaries.
Systemic capillaries •Interstitial pco2>plasma po2 •Co2 diffuses into plasma •↑ plasma pco2 •3 fates --->Co2 remains in solution --->Co2 diffuses into rbcs Co2 binds with hb Co2 converted to h2co3 H2co3 converted to hco3- and h+ Lung capillaries •Plasma pco2 > alveolar pco2 •Co2 diffuses into aveoli •↓ plasma pco2 •Hco3- and h+ → h2co3 •H2co3 → co2 and h2o •Hbco2 → hb and co2 •Co2 diffuses into aveoli
b. Which one is associated with blood ejection?
Systole
i. Is blood ejected from the ventricles during systole or diastole?
Systole
1. What is the normal effect of tsh on the thyroid gland?
T3 and t4 will be released
3. What is the difference between t3 and t4?
T3 has three iodide ions and t4 has four iodide ions. T3 is thought to the be active form of thyroxine.
4. Which lasts longer: an action potential of a muscle fiber or muscle tension of a muscle fiber?
Tension (about a 100 times!)
11. What does "primary abnormality" mean, like "primary hypercalcemia"?
That the abnormality is a direct result of a disease rather than a side-effect
5. What effect do the l-type calcium channels have on the refractory period in cardiac myocytes?
The absolute refractory period is lengthened due to the l-type calcium channels which aids in the prevention of tetany (freezing up of the heart muscle).
3. What is the role of activated myosin light-chain kinase?
The activated myosin light chain kinase causes atp to split into adp and p. The kinase uses a phosphate group from atp to phosphorylate the globular head of myosin (covalent modulation).
11. Which process is considered to be the most important component of the countercurrent multiplier system leading to a hyperosmotic medulla?
The active sodium chloride transport mechanism in the ascending limb (coupled with low water permeability in this segment) is the essential component of the system.
1. How is cardiac output defined?
The amount of blood pumped out of each ventricle in one minute or volume of blood flowing through either the systemic or the pulmonary circuit per minute. Normal cardiac output is approx. 5 l/min.
2. Describe the events that take place at the neuromuscular junction.
The axon terminals of a somatic motor neuron contain vesicles similar to the vesicles found at synaptic junctions between two neurons. The vesicles contain the neurotransmitter acetylcholine (ach). When the vesicles release the ach into the cleft, it binds the acetylcholine receptors on the muscle fiber plasma membrane.
4. How does the heart muscle receive its blood supply?
The blood being pumped through the heart chambers does not exchange nutrients and metabolic end products with the myocardial cells. Myocyte blood supply comes from the coronary arteries. These arteries exit from behind the aortic valve cusps in the very first part of the aorta. These arteries lead to a branching network of small arteries, arterioles, capillaries, venules, and veins similar to those in other organs.
2. What is the primary function of a cell body of a neuron?
The cell body (soma) is primarly responsible for signal integration.
7. What is the main function of the cerebellum?
The cerebellum is an important center for coordinating movements and for controlling posture and balance.
5. Optional: what is the role of the cerebral cortex in signal processing?
The cerebral cortex acts as an integrating area for the nervous system. Afferent information is collected and processed, and control over the systems that govern the movement of the skeletal muscles is refined.
4. What is the function of the cochlea in the inner ear?
The cochlea consists of three canals. Vibration of the stapes upon the oval window sends vibrations into the fluid of the scala vestibule. This canal along with the scala tympani contain perilymph. The scala vestibule and the scala tympani surround the scala media (cochlear duct). The cochlear duct contains endolymph. Receptors for hearing (hair cells) are located on the basilar membrane of the organ of corti within the cochlear duct. These hair cells are covered by the tectorial membrane. The vibration of the perilymph causes vibration of the tectorial membrane. Vibration of the tectorial membrane activates the hair cells.
2. W optional: what are the branches of the conducting zone?
The conducting zone extends from the top of the trachea to the end of the terminal bronchioles.
Describe the relationship between the conducting airways and gas exchange.
The conducting zone of the airways contains no alveoli and has no gas exchange with the blood.
3. Optional: what do goblet cells do?
The function of goblet cells is to produce mucus which captures foreign particles. The mucus and the foreign matter are then removed from your respiratory tract via the movement of the cilia.
4. Define electrochemical gradient. The "electro" and the "chemical" sometimes oppose each other. The "electro" and the "chemical" sometimes work in harmony. Describe those instances. You might want to go back to rmp and review it.
The driving force across a plasma membrane that dictates whether an ion will move in or out of a cell; established by both the concentration difference and the electrical charge difference between the cytosolic and the extracellular fluids of the membrane In rmp, potassium electrical gradient opposes its concentration gradient. When ap is occuring, sodium rushes into the cell because both electrical gradient (less inside) and chemical gradient (negative inside) favor its movement into the cell.
12. What does the ekg record?
The ekg is a graphic record of the heart's overall electrical activity - a combination of the individual cells' activities. The reading is a composite of the electrical activity, not a single action potential.
1. You learned about negative feedback in chapter 1 apply the concept of negative feedback to a multi-enzyme pathway.
The end product of a multienzyme pathway can inhibit an upstream enzyme. The final product slows or stops its own production by regulating a component of the process that leads to its production. This is similar to negative feedback: the result reverses (or goes against) the stimulus.
2. Which enzyme produced by the kidney is important in the control of blood pressure and sodium balance?
The enzyme renin is kidney is important in the control of the blood pressure and sodium balance
9. What is the function of the gallbladder?
The gallbladder receives bile from the liver. Here the bile is concentrated and stored. During a meal upon receipt of a hormonal signal, the gallbladder contracts and releases bile into duodenum via common bile duct.
3. How do glucose levels demonstrate dynamic constancy?
The glucose levels change with food intake and activity throughout the day, but average glucose levels for each day are relatively constant for a given individual.
2. What is the role of the hypothalamus?
The hypothalamus consists of nuclei and pathways that form the master command center for neural and endocrine coordination.
2. Describe the location and function of the juxtaglomerular apparatus. Be specific.
The juxtaglomerular apparatus is named for its proximity to the glomerulus: the macula densa portion is located on the wall of the ascending limb of the loop of henle as it becomes the distal convuluted tubule; whereas the juxtaglomerular cells are located on the wall of afferent arteriole and the distal end of the the afferent arteriole. Hence, the complex bridges between the afferent arteriole and the distal end of the ascending loop of henle of the one nephron. The juxtaglomerular cells secrete renin.
1. Optional: which substances/processes are regulated by the kidney?
The kidney's play a central role in regulating the water concentration, inorganic ion composition, acid-base balance, and the fluid volume of the internal environment (ex: blood volume)
1. By what mechanism do the kidneys regulate h+ concentration?
The kidneys maintain a stable plasma hydrogen-ion concentration by regulating plasma bicarbonate concentration. They can either excrete bicarbonate or contribute new bicarbonate to the blood.
4. what causes lactose intolerance?
The lack of lactase to break down lactose
8. What is the function of the limbic system?
The limbic system participates in learning, emotional experience, and behavior.
9. How would the loss of plasma proteins affect bulk flow?
The loss of plasma proteins would decrease reabsorption.
2. How does the anatomy of the epithelial layer of the mucosa contributed to increased surface area?
The luminal surface is folded into villi which increase surface area.
2. How do the lungs regulate h+ concentration? (by what mechanism do the lungs regulate h+ concentration?)
The lungs maintain a stable plasma hydrogen-ion concentration by regulating plasma co2.
Which two parts of the kidney make up the juxtaglomerular apparatus?
The macula densa and the juxtaglomerular cells are known as the juxtaglomerular apparatus.
2. What is the role of the middle ear in hearing?
The middle ear is separated from the external ear by the eardrum and from internal ear by oval and round window. The ossicles (malleus-hammer, incus-anvil, stapes-stirrup) are located in the middle ear. The malleus is attached to eardrum, so when the eardrum vibrates the signal is transmitted to the incus,and then on to the stapes. The stapes is attached to the oval window of the inner ear. The vibration is transmitted to the fluid in the inner ear which causes fluid vibrations.
2. Which structures in the digestive system produce substances to digest carbohydrates?
The mouth (saliva), the pancreas and the small intestine
5. What causes the blind spot?
The optic disc. It is a distinct circular region (nasal side of retina) which carries neural signals through the optic nerve (cn ii) from the eye to visual processes centers in the brain. Central retina vessels are also bundled with the optic nerve. There are no photoreceptors on the optic disc, so it's your blind spot.
3. How do the ossicles affect the force of a sound wave as it is being transferred from outer to inner ear?
The ossicles amplify the pressure of sound vibrations.
15. What is meant by sliding filament mechanism?
The overlapping thick and thin filaments in each sarcomere move past each other, propelled by movements of the cross-bridges
13. What do the following represent in the ekg? • P wave
The p wave is the result of the depolarization wave from the sa node to the av node.
7. How do the pancreas and liver secrete substances into the small intestine? Would this be considered to be exocrine or endocrine secretion?
The pancreas and liver secrete substances into the small intestine through ducts. Ductal secretion is exocrine secretion. Endocrine secretion involves transport of the substance through the blood.
8. What is the state of the membrane potential of a photoreceptor at rest (in the dark)?
The plasma membranes of photoreceptor cells are depolarized at rest and hyperpolarized in the light.
6. Which anatomical structure is responsible for the simultaneous movement of the lung surface and the thoracic wall during ventilation?
The pleural membrane Has two basic pleura layers and a space in between. The parietal pleura layer is attached to the thoracic wall; whereas, the visceral pleura layer is attached to the lung. The anatomy of the pleural membrane leads to the simultaneous movement of the lung surface and the thoracic wall.
9. In general, what is the function of the brainstem (midbrain, pons and medulla)?
The pons, midbrain, and medulla are structures in the brainstem that relay signals between the forebrain, cerebellum, and spinal cord.
13. What do the following represent in the ekg? • QRS wave
The qrs complex is the result of the ventricular depolarization (and atrial repolarization - hiding in qrs).
16. What is the role of na+ in reabsorption of other substances?
The reabsorption of many substances is coupled to the reabsorption of na+. The co-transported substance moves uphill into the cell via secondary active transport as na+ moves downhill into the cell via the same co-transporter. This is how glucose, many amino acids, and other organic substance undergo tubular reabsorption.
4. What is meant by the term "motor end plate"?
The region of the skeletal muscle fiber plasma membrane that lies directly under the motor neuron's axon terminal
9. Would the heart beat faster or slower in the absence of autonomic nervous system input?
The sa node has an inherent rate of 100 beats per minute. Changes in the heart rate would depend on which branch of the nervous system was removed. If you remove the parasympathetic input, it would beat faster. If you remove the sympathetic, it may beat slower because there is usually more parasympathetic activity on the heart than sympathetic.
13. What is the role of the sarcoplasmic reticulum in excitation-contraction coupling?
The sarcoplasmic reticulum is the intracelluar storage area for ca2+. Ca2+ will be released as a result of the action potential propagated through the t-tubules.
9. By what means is the action potential spread through the muscle cell? Be specific.
The signal is propagated into transverse tubules as it travels through the muscle fiber
3. What would happen to the membrane potential of a postsynaptic neuron if you had an excitatory input and an inhibitory input of equal size at the same time?
They would cancel each other out, so the membrane potential would not be changed
3. Compare sympathetic and parasympathetic innervation to the heart in terms of the following: neurotransmitters, receptors, atrial innervation and ventricular innervation. See figure 12-9.
The sns innervates the entire heart muscle (ventricles) and nodal cells (atrium) and release ne; whereas the psns innervates the nodal cells only and release primarily acetylcholine. The sympathetic nervous system acts on beta-adrenergic receptors; whereas the parasympathetic nervous system acts on muscarinic cholinergic receptors. The hormone epinephrine, from the adrenal medulla, binds to the same receptors as ne and exerts the same actions on the heart.
1. Optional: how does the gray and white matter arrangement differ in the spinal cord and the brain?
The spinal cord has a central area of gray matter surrounded by white matter; and the brain has a central area of white matter surrounded by gray matter.
3. Astrocytes are the most versatile type of glia. A. How does the anatomy of the astrocyte contribute to the formation of the blood brain barrier?
The star-shaped astrocytes wrap around the capillaries and form tight junctions between adjacent astrocytes.
c. How does the stimulus affect the cell membrane in both types?
The stimulus activates ion channels. This alters ion flux and initiates sensory transduction resulting in graded potentials.
7. Which structures in the digestive system produce substances to digest protein?
The stomach, the pancreas and the small intestine
13. What do the following represent in the ekg? • T wave
The t wave is caused by ventricular repolarization.
5. Explain what the term "oxygen-hemoglobin dissociation" means.
The term "dissociate" means to separate. In this case, oxygen from hemoglobin separation.
1. Which part of the brain consists of a collection of several large nuclei that serve as synaptic relay stations, and as important integrating centers for most inputs to the cortex?
The thalamus
5. What happens to the shape of the smooth muscle when the sliding filament mechanism is activated?
The thin and thick filaments slide past each other, causing the muscle fiber to shorten and thicken.
17. Describe "transport maximum". Add why this is a significant concept for diabetes.
The transport maximum (or tubular maximum) for a given substance is the maximum amount of this substance that can be reabsorbed in the proximal tubule in a unit of time [mg/min]. Binding sites are saturated, so reabsorption max is reached. This transport maximum is why untreated diabetic patients have glucose in their urine.
10. What is the role of the hepatic portal system?
The venous blood from the small intestine, containing absorbed nutrients other than fat, passes to the liver via the hepatic portal vein before returning to the heart. The liver contains enzymes that can metabolize (detoxify) harmful compounds.
4. What would happen to the ventricular and atrial rates of contraction if the av nodal function is lost?
The ventricles will contract too quickly, out of synchrony with the atria. Av node normally delays the conduction by 0.1 second to allow the ventricles to fill completely before they contract
14. How is stroke volume defined?
The volume (l) of blood ejected during each contraction.
4. Optional: what is the role of the juxtamedullary nephrons?
Their role is to generate an osmotic gradient in the medulla responsible for the reabsorption of water
5. Is "elasticity" the same as "compliance"? What is meant by the term compliance?
They're opposite: compliance is stretching and elasticity is recoiling back to original size Compliance = measure of how easily a structure can stretch
22. How does glaucoma result in retinal cell damage?
There is an increase in aqueous humor which causes an increase in pressure in the middle section of the eye. This force transfers to retina leading to damage to the retina and irreversible blindness if the pressure is not decreased.
now describe in words what happens in terms of ion permeability in a sa node action potential
There is no steady rmp at the sa node. During slow depolarization to threshold, k+ ion permeability decreases as the channels are closing. F-type na+ channels (funny) open. Ca++ channel opens briefly for a depolarizing boost. These are t-type ca++ channels (transient). At the depolarizing phase, l-type ca++ channels open, sodium channels close, and t-type calcium channels close. K+ permeability is at a low level during depolarization to threshold. Finally, during the repolarizing phase k+ channels open.
1. In skeletal muscle, calcium in the cytosol binds to troponin. What about in smooth muscle?
There isn't any troponin in smooth muscle. Calcium binds to calmodulin instead. This binding triggers the activation of a signaling cascade, resulting in activation of myosin light-chain kinase.
8. What is the role of somatic motor neurons in smooth muscle contraction?
There isn't one. The smooth muscle cells are not innervated by the somatic motor system. They are innervated by the autonomic nervous system - sympathetic and parasympathetic divisions.
10. What would happen if cardiac muscle was able to undergo prolonged tetanic contraction?
There would be prolonged contraction without relaxation, so the heart would sieze up and fail. Blood would not be supplied to the systems or brain.
1. How do intercalated discs and gap junctions contribute to synapses within the heart?
These allow for electrical synapses to be propagated between the myocytes.
1. What is meant by autorhythmic cells?
These are cells that fire spontaneously, act as a pacemaker and form the conduction system for the heart.
4. Optional: what is the role of the intercostal muscles in ventilation?
These muscles contract causing the ribs to raise and the sternum to elevate. The contraction of the diaphragm increased the thoracic volume by lowering the bottom border of the thorax, while the external intercostal muscles increase thoracic volume by raising the top border of the thorax. The anterior-posterior and lateral dimensions of the thorax increase as well.
6. What happens to polysaccharides, such as cellulose, that humans lack the enzymes to digest?
These polysaccharides become what we commonly call "dietary fiber". The fiber is passed to the large intestine where it is partially metabolized by bacteria, but for the most part excreted in feces.
3. Optional: what is the role of dense bodies in smooth muscle?
They are a site of attachment for thin filaments (actin) in smooth muscle. When the myosin cross-bridge attaches to the actin, the myosin pulls the actin as well as the dense body causing contraction of the cells.
3. How are the thick and thin filaments arranged in cardiac muscle? In this regard, cardiac muscle is more like... skeletal muscle or smooth muscle?
They are arranged as they are in skeletal muscle (sarcomeres)
4. How are the thick and thin filaments arranged in smooth muscle?
They are arranged in diagonal chains that are anchored to the plasma membrane or to dense bodies within the cytoplasm.
1. What is the function of a neuron?
They are the functional unit of the nervous system. Their primary function is to process and transmit electrical information.
2. What role do arterioles play in the regulation of blood pressure?
They are the major determinants of total peripheral resistance and consequently blood pressure.
2. Capillary anatomy is not the same throughout the body. What are the different types of capillaries and how do they differ in function?
They are typically thin-walled tubes of endothelial cells one layer thick resting on a basement membrane, without smooth muscle or elastic tissue, and separated by intercellular clefts (fenestrations, for fluid exchange). However, the size and extent of fenestration vary from organ to organ. Brain capillaries have very few (blood brain barrier). Liver and spleen capillaries have very large fenestrations, to allow recycling of old rbc. Intestinal capillaries should be well-fenestrated, to allow absorption of nutrients.
3. How do alpha and beta cells of the islets of langerhans "know" that they need to secrete their hormones?
They directly sense blood plasm glucose concentrations. If it's low, glucagon is released. If it's high, insulin is released. Figure 16.9: beta cells are also stimulated by incretins (gut hormones, released when food enters guts), increased plasma amino acids and parasympathetic activity; inhibited by sympathetic.
1. Optional: what is the relationship between "tension" and "load"?
They oppose each other Load = force exerted on the muscle by object Tenstion = force exerted on the object by muscle
1. How do veins compare to arteries in terms of wall thickness and composition?
Thin walls, less smooth muscle, less elastic lamina
13. How is compliance compromised with respiratory disease of the newborn?
This disease occurs when there is a deficiency of surfactant. Surfactant synthesizing cells may be too immature to function adequately. This causes low lung compliance --> infant can only inspire by the most strenuous efforts.
7. This is figure 17.7 on p.611. Explain the concept of negative feedback using this diagram.
This is a 3-hormone series. Gnrh stimulates anterior pituitary glands to secrete fsh & lh, and fsh & lh stimulates the gonads to secrete sex hormones. Sex hormones are the final product of the series. Gnrh-producing cells and fsh/lh-producing cells sense (using receptor proteins) high levels of sex hormones and respond by slowing down (or stopping) their hormones, so that less of the sex hormones will be produced. When the final product of a process turns off the earlier process, that's negative feedback.
9. Through which type of transport are most amino acids absorbed?
Through secondary active transport coupled with sodium movement
The lack of lactase to break down lactose
Through secondary active transport coupled with sodium movement
1. What is the protein precursor for thyroxine synthesis?
Thyroglobulin
3. What are the two types of amines? Which is water soluble and which is lipid soluble?
Thyroid hormone - lipid-soluble Catecholamines
6. What is the main function of capillaries?
To be the site of molecule exchange
7. What is the end goal of the countercurrent multiplier system of the kidney?
To create a hyperosmotic medullary interstitial fluid, so that urine can be concentrate
10. Define hypercalcemia and hypocalcemia.
Too much plasma calcium vs too little plasma calcium
3. In which direction do veins always move blood?
Towards the heart
1. How is a hormone different from other chemical messengers in the body?
Travels in blood, can go long distance using cardiovascular system
4. Identify and describe the two regulatory proteins.
Tropomyosin • Regulatory protein • Overlaps binding sites on actin for myosin, and inhibits interaction when in the relaxed state Troponin • Regulatory protein • Forms a complex with the other proteins of the thin filament (actin and tropomyosin) • Troponin binds ca2+ reversibly and once bound changes conformation to pull tropomyosin away from the myosin interaction sites
2. Which regulatory filaments are found in cardiac muscle? In this regard, cardiac muscle is more like... skeletal muscle or smooth muscle?
Troponin and tropomyosin, like skeletal muscle
8. Define competition.
Two different ligands with similar, but not identical, shapes, and chemical structures are competing for the same binding site.
7. What are the two general functions of the ecm?
Two general functions: (1) It provides a scaffold for cellular attachments (2) It transmits information, in the form of chemical messengers, to the cells to help regulate their activity, migration, growth, and differentiation.
5. What does the term "cross-bridge" represent?
Two globular heads that extend from the sides of the myosin and attach (bridge) to actin
4. What is the function of surfactant?
Type ii alveolar cells produce a substance known as surfactant. Surfactant's primary role is to reduce surface tension in the lung - this effect is necessary to prevent the collapse of the alveoli and distal airways and promote gas exchange. It increases compliance in the process.
18. Would a person under stress possibly have a delay in accommodation when attempting to view a near object?
Yes, because under stress the response of the sns would be heightened. The psns activity is needed to view near objects
8. Where in the kidney does urine get concentrated?
Urine is concentrated in the medullary collecting duct as a result of the hyperosmotic interstitial fluid.
5. What structures make one-way flow possible in veins?
Valves
8. How would arteriolar vasoconstriction affect bulk flow?
Vasoconstriction (diverts the blood to other arterioles and) lowers capillary blood pressure aka capillary hydrostatic pressure. This would decrease filtration.
Which mechanisms are controlled both locally (intrinsically) and extrinsically in the arterioles?
Vasoconstriction and vasodilation
9. What is the effect of sympathetic neural input on the afferent and efferent arterioles in the kidneys? (revisit table 6-11)
Vasoconstriction of both (blood is being diverted away from kidneys during fight-or-flight)
4. How does the action of adh lead to increased water reabsorption?
Vasopressin (adh) increases the permeability of the collecting ducts by triggering the movement of aquaporin channels from vesicles to the cell membrane.
5. Compare and contrast the effects of adh (vasopressin) and aldosterone on the formation of urine.
Vasopressin: regulates the body's retention of water by acting to increase water absorption in the collecting ducts. Increased water absorption leads to the formation of concentrated urine. Aldosterone: acts to increase the reabsorption of sodium followed by some water. Increased sodium and water reabsorption leads to the formation of concentrated urine, but adh results in more highly concentrated urine.
10. How does the effect of vasoconstriction differ between veins and arteries?
Veins - vasoconstriction increases forward flow, in other words, vasoconstriction increases venous return, edv, sv and cardiac output Arteries - vasoconstriction decreases forward flow, in other words, flow will be restricted into the capillaries; pressure will build up in the vessels prior to the vasoconstriction; afterload will increase as tpr increases
2. In terms of compliance and elasticity, how do veins compare to arteries?
Veins more compliant and less elastic than arteries d/t anatomy
3. How does the velocity of blood in the arteries compare with the velocity of blood in the capillaries?
Velocity based on total cross area - the aorta has increased blood velocity because there is only one aorta. Although it has a large diameter, the sum of all cross-section areas of the many capillaries is bigger than the aorta's. The velocity of blood slows in arteries and arterioles, and then slows again within the huge total area of the capillaries.
8. What affect does sympathetic neural input have on venous pressure and venous return to the heart?
Venoconstriction causes an increase in pressure and an increase in forward blood flow into the right atrium
9. How does venous vasoconstriction lead to increased cardiac output?
Venous vasoconstriction leads to increased cardiac output by increasing venous return and edv. Increased edv leads to increased sv and increased co.
7. The common response to both peripheral and central chemoreceptor stimulation is to increase _______.
Ventilation
3. Describe hyperventilation in terms of an increase or decrease as compared to normal for the following variables: ventilation rate, arterial co2, arterial ph, arterial h+ concentration.
Ventilation rate: high compared to metabolism Arterial carbon dioxide: low Arterial h+ concentration: low Arterial ph: high (alkaline/basic)
4. Can a person be homeostatic for one variable and not homeostatic for another? Explain with an example.
Yes, glucose could be within normal range (homeostatic), but blood pressure could be elevated (not homeostatic).
2. Describe hypoventilation in terms of an increase or decrease as compared to normal for the following variables: ventilation rate, arterial co2, arterial h+ concentration, arterial ph.
Ventilation rate: low compared to metabolism Arterial carbon dioxide: high Arterial h+ concentration: high Arterial ph: low (acidic)
3. Name the three areas of the cortex to which specific pathways travel.
Visual - visual cortex in the occipital lobe Sound - auditory cortex in the temporal lobe Odors - olfactory cortex on the undersurface of the frontal and temporal lobes and to limbic system
8. Optional: define the glomerular filtration rate (gfr).
Volume of fluid filtered from the glomerular capillaries into bowman's space per unit time
1. What is meant by renal clearance?
Volume of plasma that is cleared of a substance in one minute (ml/min)
2. What effect would vomiting have on h+ concentration?
Vomiting causes a loss of h+ which would decrease h+ concentration
1. What is the role of adh in renal absorption of water?
Water absorption in the collecting duct is controlled by vasopressin (antidiuretic hormone).
3. Which type of signal transduction occurs in figure 6-27: water-soluble or lipid-soluble?
Water-soluble
What effect does hyperventilation have on alveolar pco2?
When alveolar ventilation is excessive, more carbon dioxide will be removed from the blood stream than the body can produce. Pco2 decreases below the normal value. More info: this causes the concentration of carbon dioxide in the blood stream to fall and produces a state known as hypocapnea (too little carbon dioxide in the blood stream).
3. What is the role of calcium in the presynaptic terminal?
When the action potential reaches the presynaptic terminal, it activates voltage-gated calcium channels and calcium enters the cell. Calcium binds to synaptic vesicle proteins and trigger exocytosis of nt from vesicles. In other words, calcium acts as a second messenger.
6. Disruptions in blood flow or ventilation can result in a ventilation-perfusion inequality. Explain how.
Yes, there may be ventilated alveoli with no blood supply at all due to a blood clot. There may be blood flowing through areas of lung that have no ventilation due to collapsed alveoli.
5. How is water diuresis different from osmotic diuresis? Are sodium and water always lost together? Explain.
With water diuresis there is increased water excretion as a result of low adh or low adh activity. Osmotic diuresis occurs as a result of abnormal increases in solute in the filtrate. The solutes decrease the degree of water reabsorption. In both cases, urine output or excretion is increased. Loss of solute in the urine must be accompanied by water loss (osmotic diuresis) as solute increases cause decreases in water reabsorption leading to increased water excretion. But water diuresis is not necessarily accompanied by solute loss as this can occur through changes in adh which does not effect solute concentration.
14. What would be the consequence of a decrease in ca2+ concentration or an absence of ca2+ in terms of cross-bridge binding?
Without ca2+ ions bound, troponin holds tropomyosin over cross bridge binding sites on actin, so myosin can not bind to the actin
4. Optional: how does the absence of vasopressin affect the concentration of urine?
Without vasopressin (adh), the water permeability of the collecting duct is extremely low because the number of aqaporins in the luminal membrane is minimal and very little water is reabsorbed from these sites. Therefore, a large volume of water remains behind in the tubule to be excreted in the urine leading to water diuresis.
4. You have two compartments x and y separated by a membrane. The membrane is permeable to na+, but not cl-. At time zero, nacl is poured into compartment x and pure water is poured into compartment y. You wait, and equilibrium is reached. Add information to the drawing below to answer the following questions.
X Y
5. Is it possible for a person with one genotypic sex to appear (phenotype) to be the other sex? Describe some examples of such instances.
Yes - example in class, xy individual with mutated and nonfunctional sry gene on the y chromosome will present as phenotypic female
12. Does sodium reabsorption occur in the absence of aldosterone?
Yes! When aldosterone is completely absent, approximately 2% of the filtered na+ is not reabsorbed but excreted. Most of the filtered na+ has been reabsorbed by the time the filtrate reaches the distal parts of the nephron (which is when aldosterone is released).
8. Is it correct to say that primary active transport uses atp directly and secondary active transport uses atp indirectly? Explain.
Yes, Primary active transport - direct use of atp through hydrolysis of atp on the transporter Secondary active transport - indirect use of energy through electrochemical gradient
2. Does net flux proceed in a specific direction? If so, describe that direction.
Yes, always proceeds from higher to lower concentration
C. Will there be a potential difference across the membrane at equilibrium? If so, will side x be more negative or more positive as compared to side y?
Yes, because chloride could not move through the membrane. Side x will be more negative as compared to side y.
5. There is some ventilation-perfusion inequality normally present in a healthy person. What causes this?
Yes. Blood flow and ventilation greater at base, but not perfectly matched in any zone. Perfusion exceeds ventilation in the bases. Ventilation exceeds perfusion in the apices.
4. Optional: which process involves the movement of substances from the lumen into the blood or lymph?
a. Absorption
2. Optional: which process converts macromolecules into micromolecules?
a. Digestion
3. Optional: which process causes the release of substances into the lumen?
a. Secretion
4. B. Describe the relationship between the lumen and blood vessels to the apical side and basolateral side of epithelial tissue, by describing how a molecule moves from one side to the other.
apical side of the epithelium faces the lumen or outside world that the epithelium is separating from the body. Basal side of the epithelium faces the rest of the body, where there is always a blood vessel (to nourish the avascular epithelium). The blood vessel represents the rest of the body, because blood is used to carry substances everywhere in the body. For example, when a molecule in the lumen is absorbed into the body, it must enter through the apical side of the epithelial cell. Then it enters the rest of the through the basolateral side of the epithelial cell. There are different proteins on the apical versus basolateral sides of the epithelial cell that allows for this diretional movement of the molecule. Basal and lateral sides of these cells share common functions, so they're grouped together as "basolateral".
2. What is the role of blood in hormone delivery?
hormones are secreted and carried through the blood to the target cell
5. How can the following variables be adjusted to increase bp? a. Venous return
increase
5. How can the following variables be adjusted to increase bp? b. Edv
increase
5. How can the following variables be adjusted to increase bp? c. Autonomic neural input
increase sns, decrease psns
25. Cardiac output multiplied by total peripheral resistance equals _____. This all comes back to the purpose of the cardiovascular system: cardiovascular system must maintain a high enough blood volume and blood _____ to ensure adequate blood supply to tissues of the body.
mean arterial pressure, pressure
2. Describe receptor desensitization.
receptor doesn't respond to the nt
3. Explain how up and down regulation affect the number of receptors.
too much nt ----> less receptors = down regulation too little nt ----> more receptors = up regulation
3. Explain the effect of increased hydrogen ion concentration on ventilation. Explain the effect of decreased hydrogen ion concentration on ventilation.
• A decrease in arterial plasma hydrogen-ion concentration causes reflex hypoventilation, which raises arterial pco2 levels leading to increases in hydrogen-ion concentration via the bicarbonate buffering system • A increase in arterial plasma hydrogen-ion concentration causes reflex hyperventilation, which lowers arterial pco2 levels leading to decreases in hydrogen-ion concentration via the bicarbonate buffering system
1. Apply labels to the figure below explaining receptor-mediated endocytosis. Try to label it yourself and then check it against figure 4-21 in the book. You should also describe the process of receptor-mediated endocytosis using a clathrin-coated pit in writing.
• A ligand binds to a receptor causing conformational change • Clathrin, a cytosolic protein, is recruited to the plasma membrane • Clathrin forms a cagelike structure which leads to an aggreagation of ligand bound receptors into a localized region of the membrane, forming a depression, or clathrin-coated pit • The pit invaginates and pinches off to form a clathrin-coated vesicle. • The vesicle then merges with an endosome or other organelles or lysosome or carries ligand from one side of the cell to another. O E.g. Cholesterol enters via this process • Process can be regulated O Increased cholesterol, decreased # receptors O Decreased cholesterol, increased # receptors
12. What is meant by excitation-contraction coupling? In this explanation, you'll have to describe the relationship between troponin, tropomyosin, ca2+ and myosin.
• A sequence of events by which an action potential in the plasma membrane of a skeletal muscle fiber leads to cross-bridge activity (action between thick and thin fibers resulting in muscle contraction) • Sequence of events -An action potential at the skeletal plasma membrane does not act directly on contractile proteins, but instead increases cytosolic ca2+ -Ca2+ binds to troponin which allows troponin to bind to tropomyosin resulting in activation of the cross bridges and contraction -Contraction is terminated by removal of ca2+ from troponin by lowering ca2+ levels; ca2+-atpases pump calcium ions from cytosol back into the sarcoplasmic reticulum
2. For each class of neurons, answer the following questions. B. In which branch of the nervous system would each type of neurons cell bodies, dendrites, and axons be located?
• Afferent - cell bodies and dendrites in pns; axons in pns and cns • Efferent - cell bodies and dendrites in cns; axons in pns and cns • Interneurons - cell bodies, dendrites, and axons in cns
2. For each class of neurons, answer the following questions. A. In what direction does each class transmit information?
• Afferent - in; from tissues and organs of the body toward the cns • Efferent - out; cns to effector cells (neurons, muscles, glands) • Interneurons - between afferent and efferent entirely within the cns
2. For each class of neurons, answer the following questions. C. What is the primary function of each class?
• Afferent - sensory receptors (sense environmental changes and send signals to cns) • Efferent - motor neurons (initiate signals to muscles, neurons, and glands) • Interneurons - integrate information (analyze the sensory information, store some aspects and to make decisions regarding appropriate response)
6. List all adrenal cortex hormones and the function of each.
• Aldosterone (mineralocorticoid) - increase sodium/decrease potassium concentration in plasma • Cortisol (glucocorticoid) - stress response • Androgens - sex hormone; gets converted into testosterone
5. Describe which way blood flows in veins and in arteries, in reference to the heart.
• All arteries carry blood away from the heart to the systems and pulmonary circulation. • All veins carry blood to the heart from the systems and pulmonary circulation.
2. What are the three classes of hormones? How is each class different from the other two?
• Amine - derivatives of the amino acid tyrosine, smallest, most are water-soluble messengers except thyroid hormones • Peptide/protein - bigger than amines but vary greatly in size, generally water-soluble • Steroid - lipid-soluble
8. What effect do temperature, dpg, high-acidity and ph have on the oxygen-hemoglobin dissociation curve?
• Any increase of any of these factors causes the dissociation curve to shift to the right • This means, at any given po2, hemoglobin has less affinity for oxygen and dissociate (release) oxygen gas more readily. Vice versa is also true! A decrease in any of these factors would cause a left shift ---> at any give po2, hemoglobin has a great affinity for oxygen.
2. Water can move through cell membranes using a transmembrane channel. What is the name of the transporter that can move water? What type of transport is this?
• Aquaporins • Facilitated diffusion (passive)
3. Describe the fovea centralis' anatomy and function.
• Central shallow pit within the macula densa containing a high-density of cones • Area of high visual acuity
10. Identify three ways in which signal transduction could be inactivated. Explain how each one works.
• Cessation of receptor activation O Decrease in the concentration of first messenger molecules in the region of the receptor. This occurs as enzymes in the vicinity metabolize the first messenger, as the first messenger is taken up by adjacent cells, or as it simply diffuses away. O The receptor becomes chemically altered (usually by phosphorylation), which may lower its affinity for a first messenger, and so the messenger is released. Phosphorylation of the receptor may prevent further g protein binding to the receptor. O Plasma membrane receptors may be removed when the combination of first messenger and receptor is taken into the cell by endocytosis.
1. There are multiple ways that receptor activation brings about an intracellular response. Explain what is meant by "membrane potential change" and "metabolism".
• Change in permeability ---> membrane potential - -40mv to -80mv is the range; used as a signal • Metabolism - activate catabolism (like epinephrine on liver cells activating lipolysis) or anabolism (like insulin on liver cells activating glycogenesis) • Repositioning of a transport proteins - move from cytosol to membrane • Secretory activity - inhibit or activate • Proliferation and differentiation - increase or decrease rate of cell multiplication and specialization • Contractile or other activities
1. Optional: how do smooth muscle cells compare to skeletal muscle cells in terms of ability to divide?
• Skeletal muscle - no replication • Smooth muscle - replicate
5. How do colloids affect osmotic force of blood plasma?
• Colloids (plasma proteins) are unable to move through capillary pores (very low concentration in the isf), so they're trapped inside the capillary; this makes water concentration of the plasma slightly lower (by about 0.5%) than isf; creates osmotic force to induce flow of water from isf into capillary
10. How does vasoconstriction of afferent arterioles affect flow, glomerular hydrostatic pressure and gfr?
• Constriction of the afferent arterioles decreases flow, glomerular capillary hydrostatic pressure, and gfr
11. How does vasoconstriction of efferent arterioles affect flow, glomerular hydrostatic pressure and gfr?
• Constriction of the efferent arteriole increases flow, glomerular capillary hydrostatic pressure, and gfr; it tends to "dam back" the blood in the glomerular capillaries
3. How do juxtamedullary nephrons differ from cortical nephrons?
• Cortical nephrons are located in the outer cortex. Their loops of henle do not penetrate deep into the medulla. • The renal corpuscles of the juxtamedullary nephrons lie in the part of the cortex closest to the cortical-medullary junction. Their loops of henle plunge deep into the medulla.
When the photoreceptor is "at rest", is it in the dark or being stimulated with light?
• Dark - at rest • Light - not at rest
7. How does bp and baroreceptor activity correlate with adh release?
• Decreased bp - decreased firing of baroreceptors - decreased signals to hypothalamus - increased vasopressin release • Increased bp - increased firing of baroreceptors - increased signals to hypothalamus - decreased vasopressin release
3. What effects does cortisol have on the immune system? Describe the pros and cons of these effects.
• Demonstrates anti-inflammatory and anti-immune actions (puts a break on the immune system) A. Inhibits the production of both leukotrienes and pgs B. Stabilizes lysosomal membranes in damaged cells, so prevents the release of contents C. Reduces capillary permeability in injured areas (less edema) Suppresses growth and function of certain key immune cells
11. How is each type of junction suited to the types of tissues each is located in? Give specific examples of tissue types for each type of junction.
• Desmosomes are well-suited for tissues that need to stretch; e.g. Between epithelial cells in the skin • Tight junctions are well-suited for areas that need to be tightly controlled; e.g. Blood brain barrier, intestine • Gap junctions are well-suited for areas where cells need to communicate rapidly; e.g. The heart
8. What is happening to the diaphragm, ribs and intercostal muscles during expiration?
• Diaphragm: during normal expiration (breathing out), the diaphragm relaxes allowing the air to flow out as the lungs recoil • Ribs: lower and are drawn inward • Intercostal muscles: relax
How does decreased vasoconstriction to the afferent and efferent arterioles affect flow, glomerular hydrostatic pressure and gfr?
• Dilation of the afferent arterioles increases flow, glomerular capillary hydrostatic pressure, and gfr • Dilation of the efferent arteriole decreases flow, glomerular capillary hydrostatic pressure, and gfr
18. Identify some of the substances eliminated from the body through secretion.
• Drugs and drug metabolites • Waste products such as urea, uric acid, and creatinine • Ions such as potassium, sodium, hydrogen
1. What is the effects of increased plasma cortisol on cellular metabolism during stress?
• Ensures basal level of glucose O For example, increase glucose release from the liver
j. During which of the four major phases does blood enter or exit the ventricles?
• Enter ventricles - ventricular filling • Exit ventricles - ventricular ejection
1. What are the differences between an excitatory and inhibitory post-synaptic potential in terms of threshold? ("in terms of threshold" means your answer has to include the word 'threshold') which ions crosses the membrane (or "membrane permeability increases to which ions?") In each case?
• Epsp - brings the membrane potential of the postsynaptic neuron closer to threshold (depolarized) O Na+ permeability increases and na+ moves into the cell - cell is depolarized • Ipsp - drives the membrane potential of the postsynaptic neuron farther away from threshold (hyperpolarized) O Activated receptors on the post-synaptic membrane open cl- or k+ channels ; cl- permeability and k+ permeability increase O Cl- enters cell, so the cell becomes more negative than the resting potential; k+ leaves the cell, so cell becomes more negative - cell is hyperpolarized
1. Explain filtration, reabsorption and secretion in terms of the direction of fluid movement. Be specific.
• Filtration - movement of some of the plasma from the glomerular capillaries into bowman's space • Reabsorption - movement of substances from the tubular lumen to the peritubular capillaries • Secretion - movement of substances from the peritubular capillaries to the tubular lumen; this is the opposite of reabsorption
4. Explain the direction of fluid movement in filtration and reabsorption.
• Filtration = fluid into interstitial space from the plasma • Reabsorption = fluid back into plasma from the isf
6. What is the difference between a first and second messenger? Which messenger works intracellularly and which works intercellularly?
• First messengers - intercellular messengers that bind to receptors on the extracellular surface of plasma membrane • Second messengers - substances that enter or are generated in the cytoplasm as a result of receptor activation by the first messenger, used to amplify the response • First messengers - intercellular messengers • Second messengers - intracellular messengers
5. What is the difference between a glomerular capillary and a peritubular capillary in terms of location and function?
• Glomerular capillaries: globular tufts of capillaries responsible for filtration into bowmans space • Peritubular capillary: surround the nephrons and are responsible for reabsorption from tubule to plasma as well as secretion from plasma to tubule
4. Neurons have three basic parts: dendrites, cell bodies, and axons. Which of these parts would you expect to find in gray matter, and which would you expect to find in white matter?
• Gray matter - cell bodies (nuclei) and dendrites • White matter - myelinated axons organized into tracts
2. What is the effects of increased plasma cortisol on the cardiovascular system during stress?
• Helps maintain normal blood pressure (permissive actions on reactivity of arterioles to epinephrine and norepinephrine)
2. How does an increase/decrease in pressure difference affect flow? How does an increase/decrease in resistance affect flow? Remember: "how does x affect y" means "does y increase or decrease when x increases" and " does y increase or decrease when x decreases"
• If the pressure difference changes independent of resistance, the flow will change in the same direction as the pressure difference; for example, if the pressure difference increases, flow will increase or if the pressure difference decreases, flow will decrease • If the resistance changes independent of the pressure difference, the flow will change in the opposite direction as the resistance; for example, if the resistance increases, flow will decrease or if the resistance decreases, flow will increase
1. Would acidosis or alkalosis result in an increase in hco3- reabsorption in the kidneys?
• In metabolic acidosis, there is increased h+ concentration and decreased hco3- concentration. Additional bicarbonate will be reabsorbed to help return the body to a neutral state. Hence, reabsorption is increased. • In metabolic alkalosis, there is decreased h+ concentration and increased hco3- concentration. Additional bicarbonate will be secreted to help return the body to a neutral state. Hence, reabsorption is decreased.
7. What are the actions of the sympathetic nervous system during stress? Include the effects of adrenal medulla stimulation.
• Increase heart rate • Open airways • Decrease digestion • Stimulate epinephrine secretion from adrenal medulla, and epinephrine enhance the actions of sympathetic plus increase glycogenolysis and triglyceride break-down
6. How does a baroreceptor respond to increases or decreases in blood volume?
• Increased blood volume, increased blood pressure, increased firing of the baroreceptors • Decreased blood volume, decreased blood pressure, decreased firing of the baroreceptors
7. What affect does increased baroreceptor (afferent) activity have on the autonomic nervous (efferent) system?
• Increased firing of the baroreceptors --> decreased sns and increased psns activity • Decreased firing of the baroreceptors --> increased sns and decreased psns activity
2. What is the effect of increase in hydrogen ion concentration on carbon dioxide and bicarbonate levels?
• Increased h+ - equation to the left; more h+ combines with buffer, so less hco3- and more co2
why can the frank-starling mechanism also be described as length versus tension?
• Increases in edv cause increased stretching of sarcomeres (fibers are stretched to a certain length) • Stretching cardiac cells overlap thin and thick fibers, but also stretch cells beyond their optimum length. This decreases the space between thin and thick filaments. Cross bridges can then bind easier. More cross bridge activation e will lead to a greater the force of contraction due to a greater tension between the fibers. This will result in a greater stroke volume.
3. What effect would ventilatory changes have on h+ concentration?
• Increasing ventilation or hyperventilation would decrease h+ concentration through a decrease in co2 • Decreasing ventilation or hypoventilation would increase h+ concentration through an increase in co2
13. What effect does anp have on sodium reabsorption, excretion, and gfr?
• Inhibits sodium reabsorption in several tubules • Increases gfr by acting on renal arterioles • Inhibits aldosterone secretion increasing na+ excretion
6. What is the effect of stress on the following? • Insulin • Glucagon • Aldosterone • Adh • Prolactin • Gh • Acth
• Insulin --> decrease • Glucagon --> increase • Aldosterone --> increase • Adh --> increase • Prolactin --> decrease • Gh --> decrease • Acth --> increase
4. How does the term transcription factor relate to lipid-soluble messengers? Do the processes of transcription and translation take a long time or a short time? Big commitment or small commitment?
• Intracellular receptor/ligand complex acts as transcription factor and binds directly to recognized sequences in the dna and alter dna transcription (activates/inhibits) • Changes in transcription will lead to changes in protein production (more or less) • Big commitment by cell, takes a while
2. What are the four minor (more detailed) phases of the cardiac cycle?
• Isovolumetric ventricular contraction • Ventricular ejection • Isovolumetric ventricular relaxation • Ventricular filling
5. Explain the pressure differences exerted on the heart valves during each minor phase in the cardiac cycle. Are the valves open or closed in each phase?
• Isovolumetric ventricular contraction - all valves closed ventricular pressure > atrial pressure; aortic pressure and pulmonary trunk pressure > ventricular pressure • Ventricular ejection - ventricular pressure > atrial pressure; ventricular pressure > aortic pressure and pulmonary trunk pressure • Isovolumetric ventricular relaxation - all valves closed ventricular pressure > atrial pressure; aortic pressure and pulmonary trunk pressure > ventricular pressure • Ventricular filling - atrial pressure > ventricular pressure; aortic pressure and pulmonary trunk pressure > ventricular pressure
3. What is the relationship between resistance and length, viscosity and radius? This relationship is expressed in an equation. How does length, viscosity and radius affect resistance?
• Length and viscosity are directly proportional to resistance; for example, increases in viscosity or length will cause increases in resistance or decreases in viscosity or length will cause decreases in resistance • The radius is indirectly proportional to resistance; for example, increases in the radius will result in decreases in the resistance or decreases in the radius will result in increases in the resistance
11. Color vision begins with activation of photopigments in the cones. What are the different types of cones?
• Long wavelengths ("l" cones) = red cones • Medium wavelengths ("m" cones) = green cones • Short wavelengths ("s" cones) = blue cones
1. Identify the three factors that would decrease synaptic strength.
• Lower amounts of nt released • Receptor desensitization • Down regulation of receptors
3. Name the five types of sensory receptors. Describe each type's adequate stimulus.
• Mechanoreceptors - respond to mechanical stimuli, such as pressure or stretch; responsible for touch, blood pressure, muscle tension • Thermoreceptors - detect sensations of cold and warmth • Photoreceptors - respond to particular ranges of light wavelengths • Chemoreceptors - chemicals, such as oxygen or co2; monitor ph • Nociceptors - specialized neuronal endings that respond to painful stimuli; heat, tissue damage
2. Explain the actions of thyroid hormones in growth and development.
• Necessary for normal production of growth hormone • Important for neurological development in the fetus • Axon terminals, synapses, growth of dendrites and formation of myelin • Congenital hypothyroidism - neural and growth abnormalities • Mother with iodine deficiency • Important for proper nerve and reflex function in adults
19. Do all the tubule segments have the same functions? Explain.
• No, the division of labor varies. O Pct - reabsorb most water and solutes such as glucose, na+, and hco3-; major site of solute secretion except k+ O Lh - reabsorb solutes such as na+ and minimal water; water reabsorbed in the descending limb, but not in the ascending limb O Dct/cd - fine tuning, determine the final amounts excreted in the urine by adjusting rates of reabsorption and, in a few cases, secretion of substances such as k+
20. Explain how sympathetic regulation through norepinephrine and hormonal control through epinephrine increase contractility.
• Norepinephrine (ne) at beta-adrenergic receptors = increases contractility independent of changes in volume • Epinephrine (adrenal medulla) acts at beta-adrenergic receptors = increases contractility independent of changes in volume
2. How do ganglia differ from nuclei in the nervous system?
• Nuclei are groups of cns neuronal cell bodies. • Ganglia are groups of pns neuronal cell bodies.
1. How do the functions of the optical and neural components of the eye differ?
• Optical component: focuses the visual image on the receptor cells • Neural component: transforms the visual image into a pattern of graded and action potentials
15. What kind of transport systems are used for reabsorption? Give an example of substances transported by these processes.
• Passive transport (diffusion, facilitated transport): ex: na+ • Active transport: ex: na+/k+-atpases
7. based on your answers for #8 and 9, you know that net filtration affects gfr. What are two other factors that influence gfr?
• Permeability of glomerular capillary (corpuscular) membranes • Surface area available for filtration
4. What effects does cortisol have on development and growth?
• Proper differentiation of numerous tissues and glands, including various parts of the brain, the adrenal medulla, the intestine and the lungs • Important inducer of surfactant production
10. What is a gap junction?
• Protein channels linking the cytosols of adjacent cells • Connexins are special proteins that compose the channel that links the two cells • Cells come within 2-4 nm of each other • Small ions and molecules can pass between cells, e.g. Cardiac cells
17. How does parasympathetic and sympathetic activity at the ciliary muscle differ with the distance of the object from the eye?
• Psns-near • Sns-far
16. How is the shape of the lens altered by parasympathetic and sympathetic stimulation?
• Psns-rounded shape • Sns-flattened shape
8. How are rapidly adapting receptors different from slow adapting receptors?
• Rapidly adapting receptors: generate a receptor potentials and action potentials at the onset of a stimulus, but very quickly cease responding • Slow adapting receptors: maintain a persistent receptor potential with a constant stimulus, which initiates action potentials in afferent neurons for the duration of the stimulus
1. Identify the two major ways of controlling protein activity.
• Regulating protein synthesis and degradation - determines amount and type of protein in a cell • Changing protein shape - alters binding of ligands
What is the primary abnormality in each of the four main types of acid-base disorders?
• Respiratory acidosis- altered alveolar ventilation (the respiratory system fails to eliminate co2 as fast as its produced ); co2 is increased • Respiratory alkalosis- altered alveolar ventilation (the respiratory system eliminates carbon dioxide faster than it's produced); co2 is decreased • Metabolic acidosis-excessive production of acid (h+) other than from co2 or excessive loss of hco3-; h+ is increased • Metabolic alkalosis- loss of acid (h+) other than from co2 or excessive retention of hco3-; h+ is decreased
2. Which ions move across the membrane in depolarization when compared to a resting cell? Which ions move across the membrane in repolarization when compared to a resting cell? ("how does the ion permeability of the membrane differ in depolarization and repolarization when compared to a resting cell?")
• Resting - more permeable to potassium • Depolarization - more permeable to sodium • Repolarization - more permeable to potassium
6. What mechanisms are utilized in the small intestine to increase digestion and absorption?
• Secrete enzymes to breakdown sugars, fats and proteins • Mix luminal contents with secretions through action of the muscles in the intestinal wall • Muscular movement causes villi movement which brings the contents into contact with the epithelial surface for absorption and slowly advances the luminal material toward the large intestine
7. Apply labels to the figure below differentiating between simple diffusion, facilitated diffusion, and active transport. Try to label it yourself and then check it against figure 4-10 in the book. You should also describe in words what is happening in each situation in terms of concentration and direction of movement.
• Simple diffusion - molecules moving through a membrane from high to low concentration with the concentration gradient, no energy required • Facilitated diffusion - molecules moving through a channel or carrier in a membrane from high to low concentration with the concentration gradient, no energy required • Active transport - molecules moving through a transporter in a membrane from low to high concentration against the concentration gradient, energy required
2. How does smooth muscle compare to skeletal muscle in terms of striations, sarcomeres and myofibrils?
• Smooth muscle - thick and thin filaments are not organized into myofibrils, no sarcomeres, no striations • Skeletal muscle - thick and thin filaments organized into myofibrils, sarcomeres, striations
9. How does the effect of sympathetic neural input on forward flow differ between veins and arteries? This will seem contradictory and will need explanation.
• Sns causes constriction of arterioles which reduces forward flow, because the narrowing blocks blood from coming into the arteriole • Sns causes constriction of veins which increases forward flow, because the narrowing squeezes the blood that's already there
3. What are the effector cells of the somatic motor neurons? What are the effector cells of the autonomic motor neurons?
• Somatic - effector cells are skeletal muscle cells • Autonomic - effector cells are smooth and cardiac muscle, glands and neurons in the gi tract
9. What effect does ligand concentration have on specificity, affinity, saturation and competition? (note: "what effect" means "increase, decrease, or no effect". For example, does ligand concentration increase or decrease specificity? Then, does ligand concentration increase or decrease affinity? Etc.)
• Specificity and affinity are not directly affected. • Saturation is directly affected. • Increased concentration could increase competition.
1. How is a "stimulus" different from an "adequate stimulus"?
• Stimulus - energy or chemical that impinges upon and activates a sensory receptor • Adequate stimulus - type of stimulus to which a particular receptor responds in normal functioning; for example, light on a photoreceptor
2. What are the four minor (more detailed) phases of the cardiac cycle? a. How does each phase relate to systole or diastole?
• Systole - isovolumetric ventricular contraction, ventricular ejection • Diastole - isovolumetric ventricular relaxation, ventricular filling
1. What are the two major phases of the cardiac cycle? Describe briefly.
• Systole : contraction • Diastole : relaxation
3. Describe four factors that affect the magnitude of net flux.
• Temperature O Higher = greater movement, greater flux • Mass of the molecule O Larger (protein) = lower speed, smaller flux • Surface area O Greater surface area for diffusion, greater flux • Medium through which molecules are moving O Molecules diffuse more rapidly in air than in water, membrane composition affects diffusion (less viscous = greater flux)
2. What is the difference between temporal and spatial summation?
• Temporal summation - a second synaptic potential adds its signal to another synaptic potential while the cell is still depolarized causing a greater depolarization. Time separates the two signals. • Spatial summation - two synaptic potentials found at two different locations on the cell add to produce a greater degree of depolarization. Space separates the two signals.
4. Explain the difference between systemic and pulmonary circulation.
• The pulmonary loop carries blood from the right-side of the heart into the lungs to be oxygenated, and then back to the left side of the heart. • The systemic loop carries blood from the left-side of the heart to the rest of the body eventually returning the blood to the right-side of the heart
1. Differentiate between a tract and a nerve.
• Tracts are groups of axons traveling/bundled together in the cns. • Nerves are groups of axons traveling/bundled together in the pns.
5. How does the role of type i alveolar cells differ from that of type ii?
• Type 1 alveolar cells are specialized to serve as very thin, gas-exchange components of the blood-air barrier (respiration membrane). • Type ii alveolar cells are secretory cells. They secrete surfactant.
8. Where (on the plasma membrane or in the cytoplasm) are the receptors for different types of hormones? Why?
• Water-soluble: on the plasma membrane, because hormone cannot cross the non-polar plasma membrane • Lipid-soluble: in the cytoplasm
10. What neural stimulation begins the ventilation process? What does the muscle response do to the volume and pressure inside the lungs?
• When activation of the phrenic nerves occur, the diaphragm contracts, moving downward into the abdomen, and enlarges the thorax for inhalation. • Increased volume = decreased pressure. The pressure of the alveolar spaces decreases to less than atmospheric (palv < patm) • Air flows from areas of higher pressure to lower pressure, into the lungs
6. What do the x-axis and y-axis represent on the oxygen-hemoglobin dissociation curve?
• X-axis: po2 (mmhg) • Y-axis: hemoglobin saturation (%)
1. Define "binding site", "ligand", "chemical specificity", "affinity", and "saturation".
•Binding site - region of the protein to which the ligand binds •Ligand - any molecule or ion that is bound to a protein •Chemical specificity - the ability of a protein binding site to bind specific ligands •Affinity - the strength of ligand and protein binding O High-affinity - tightly bound O Low-affinity - weakly bound o Intermediate-affinity - intermediate bond • Saturation - the fraction of binding sites occupied by ligands
1. Name the three ways that co2 is transported in the blood.
•Dissolved co2 -Side note: carbon dioxide is much more soluble in blood than oxygen -About 5 % of carbon dioxide is transported unchanged, simply dissolved in the plasma •Bound to hemoglobin and plasma proteins -Side note: carbon dioxide combines reversibly with hemoglobin to form carbaminohemoglobin. Carbon dioxide does not bind to iron, as oxygen does, but to amino groups on the polypeptide chains of hemoglobin. •Bicarbonate ions (hco3-) -Side note: the majority of carbon dioxide is transported in this way -Carbon dioxide enters red blood cells in the tissue capillaries where it combines with water to form carbonic acid (h2co3). This reaction is catalysed by the enzyme carbonic anhydrase (c.a.), which is found in the red blood cells. Carbonic acid then dissociates to form bicarbonate ions (hco3- ) and hydrogen ions (h+).
5. Apply labels to the figure below differentiating between a cell placed in a hypertonic, isotonic, and hypotonic solution. Try to label it yourself and then check it against figure 4-19 in the book. You should also indicate in words which way the water is moving and what is happening to the size of the cell.
•Isotonic solutions - non-penetrating solute concentration same as the ecf/icf O Do not cause a change in cell size • Hypotonic solutions - non-penetrating solute concentration lower than ecf/icf O Water moves into cells, cells swell • Hypertonic solutions - non-penetrating solute concentration higher than ecf/icf O Water moves out of the cells, cells shrink
4. How is pure water concentration changed by the addition of solute?
↑ osmolarity (more solute) = ↓ water concentration
4. Relate map, co, and tpr to the f, p and r of the "f = ∆p/r" formula.
∆p = map F = co R = tpr
