EXAM 3 - BIO360

Blood flow through vessel A, 1 mm in diameter, occurs with a 10 kPa pressure gradient from one end to the other. Blood flow through vessel B, 2 mm in diameter, occurs with a 1 kPa pressure gradient from one end to the other. Other conditions are identical. Compared to vessel A, blood flow in vessel B is ____.

1.6 times faster

If the mean arterial pressure is 100 mm Hg and cardiac output is 5 liters per minute, calculate the total peripheral resistance. Mean Arterial Pressure = Cardiac Output x Total Peripheral Resistance

20 mm Hg min liter-1

If heart rate is 100 beats per minute and cardiac output is 5000 ml/min, then stroke volume is ______. Cardiac Output = HR x SV

50 ml

Calculate the partial pressure of oxygen at a barometric pressure of 500 mm Hg if oxygen is 20% of the air.

500 x .2 = 100 mmHg

Protein deficiency tends to cause edema because __________.

A decrease in plasma protein levels reduces the osmotic force driving fluid into the capillary.

4. What mechanisms are involved in capillary fluid exchange and what role does the lymphatic system play? What is osmotic pressure and which direction does water move?

By diffusion - Water flows from a solution of high water concentration to solution of low water concentration. - Blood pressure (hydrostatic pressure) pushes blood out of capillary, osmotic pressure pushes water in. At arteriole end Blood pressure is higher than osmotic pressure so fluid is forced out leaving solutes. Moving towards the capillary end, pressure inverts, then fluid comes back to capillaries, the exchange happens when both pressure are at eq. thats when stuff moves along it's conc. grad. - small portion of fluid goes to lymphatic system (~10%) brings it back to circulation, the lymph system helps you body by being another line of security for pathogens

How do each of these impact alveolar and arterial PO2, PCO2, and ventilation? How does exercise impact these variables? What mechanisms help us adapt to exercise? How does the body regulate ventilation in response to changes in blood gases or pH? Where are these changes sensed, and what are the physiological outcomes? Understand ventilation perfusion matching

If perfusion (blood flow) is greater than airflow, gases don't have time to exchange properly: CO2 is high: causes bronchodilation, increases airflow O2 is low: causes vasoconstriction of pulmonary capillaries, decreases blood flow If perfusion (blood flow) is slower than airflow, excess gas exchange may occur: CO2 is low = bronchoconstriction, decreased airflow O2 high: vasodilation of pulmonary capillaries, increases blood flow

What role can osmosis play in these conditions?

Osmotic flow of water in the intestinal lumen results in massive diarrhea that can be life threatening due to dehydration and decreased blood volume that leads to circulatory shock.

12. Understand how gas exchange occurs. How do gases get into and out of the body? What are the driving forces? How are they transported in the blood?

Oxygen-pp's transported by being bound to hemoglobin

7. Understand the mechanisms that regulate contraction of the heart. What role do pacemaker cells play?

Pacemaker cells are the intrinsic conduction system which is what makes the heartbeat. The SA node is the fastest and sets the pace of the heart (about 70-80 action potentials at rest). The AV node is the second fastest and only set s pace when the AV node is damaged (40-60 action potentials at rest) and has a 100ms delay. The Bundle of His is the slowest and not life staining (20-40 action potentials) and action spreads to the ventricles.

Select the statement that is TRUE during expiration?

Palv is greater than Patm, Palv − Patm is positive and airflow is outward

8. How do the sympathetic and parasympathetic nervous systems alter heart rate and contractility?

Parasympathetic nervous system decreases the heart via acetylcholine. It opens K+ channels, depress Ca+ and Na+ to get a slower threshold. Decrease in firing the SA node —> decrease in AV node —> increase in AV node delay —> shorter plateau = weaker contraction. Sympathetic nervous system increases the heart rate via epinephrine and increases contraction via more calcium. An increase in Na+ and Ca+ makes a faster threshold. Increase in Ca2+ influx —> opening of L-channels —> SA node fires more often —> AV more delay decreases = increased speed of atrial and ventricle contractions. More Ca+ to the muscle = stronger contraction force.

Choose the TRUE statement about dialysis.

Potassium levels in the dialysis tubing should be similar to the normal regulated blood potassium level.

Why does vomiting often cause a reduction in breathing rate?

Reduced breathing causes an increase in PCO2 which lowers pH toward the setpoint after vomiting causes a loss in acid and rise in blood pH.

Select the correct sequence of structures that inulin (a filtered, non-absorbed compound) will travel through in the urinary system.

Renal artery, afferent arteriole, proximal tubule, loop of Henle, distal tubule, collecting duct, ureter, bladder, urethra

Compared to the arteries, speed of blood flow in the capillaries is __________.

Slower

Select the TRUE statement.

The P wave occurs during ventricular diastole.

What level and duration of hypoxia are required to see a change in the partial pressures of oxygen?

The PO2 of arterial blood is determined primarily by the oxygen-diffusion capacity of the lung, whereas the total amount of oxygen in the blood is also dependent on the amount of hemoglobin there to carry oxygen.

What ions are involved?

The SA node cells: Na+ channels open at -60mV, Na+ enters the cell, briefly depolarize, low depolarization at -50mV, Ca+ enters the cell, open threshold at -40mV, more Ca+ enters and is at full depolarization, the voltage gated K+ channels open at +10mV and K+ leaves the cell, cell repolarizes and repeats.

What factors cause edema?

An accumulation of fluid in interstitial spaces. Can be caused by heart failure, injury, high blood pressure, or an abnormal decrease in plasma proteins.

Select the correct order of blood flow through the heart.

Vena cava Right atria Right ventricle Pulmonary artery Pulmonary vein Left atria Left ventricle Aorta

What role does venous return play?

Venous return depends on length tension and contractility which effects stroke Volume. Depending on the amount of blood produced and the optimal number for the heart when It stretches

What does it mean to be anemic?

You have less hemoglobin in your blood.

Which of the following will tend to increase arterial blood pressure? (Select all that apply.)

a. Increase in cardiac output b. Increase in plasma volume

Which of the following usually occur during exercise? (Select all that apply.)

a. Increase in sympathetic nervous system output b. Increase in stroke volume

Choose the statement that is TRUE.

a. Most digestion occurs in the stomach. b. Most of the fluid absorbed by the gut is absorbed by the large intestine. --> c. Cells in the stomach wall include muscle cells, neurons, endocrine cells, acid-secreting cells, and mucous-secreting cells. d. The liver secretes acidic bile.

Select the likely consequences of a gallstone that blocks the bile but not the pancreatic duct. (Select all that apply.)

a. Poor fat digestion b. Jaundice (yellow tint to skin)

Select the TRUE statement(s) about respiratory diseases. (Select all that apply.)

a. Severe mountain sickness can cause pulmonary edema. b. Smoking often damages alveolar walls, making oxygen delivery difficult or impossible. c. Severe mountain sickness causes pulmonary edema due to high pressures in the pulmonary artery, induced by hypoxia and the sympathetic nervous system.

Which of the following statements are TRUE about the structure of hemoglobin? (Select all that apply.)

a. The hemoglobin molecule is a protein made up of four subunits bound together. b. Each of the four heme groups in a hemoglobin molecule contains one atom of iron (Fe2+), to which molecular oxygen binds.

Select the TRUE statements about pulmonary surfactants? (Select all that apply.)

a. They are secreted by alveolar cells b. They lower the surface tension at the alveolar surface c. They are made of lipids and proteins

What intestinal processes would be inhibited by a toxin that blocked the basolateral Na+/K+ ATPases on the intestinal epithelium? (Select all that apply.)

a. Transport of glucose into the epithelium across the apical membrane b. Transport of potassium into the epithelium across the basolateral membrane

Choose the TRUE statement(s) about a drug that blocks the ability of vasopressin to bind to its receptors on the collecting duct. (Select all that apply.)

a. Urinary water output will increase. b. This drug could be very dangerous for a person deprived of water in the desert.

Choose the TRUE statement(s) about animal respiratory systems. (Select all that apply.)

a. Water breathers have to work harder to get oxygen because there is less oxygen in water than air and water is heavy. b. Unlike air-breathers, water-breathers tend to be the same temperature as their medium, because water has a higher thermal conductivity than air.

Excessive consumption of calcium, and high calcium levels in the blood will likely cause ____________.

lowering levels of parathyroid hormone

20. How are vertebrate (mammals, reptiles, birds, amphibians) and invertebrate hearts similar? Different?

mammals and birds all have 4 chambered heart. Invertebrates have open circulatory systems. Vertebrates have closed circulatory systems

6. What role do plasma proteins play in capillary fluid exchange? How can liver disease impact capillary fluid exchange? Be familiar with ECGs and the information they provide.

the plasma is very similar to interstitial fluid, helps O2 diffuse to tissue and decrease hydrostatic (blood) pressure, liver disease decreases fluid exchange b/c of increased pressure on portal vein (cirrhosis), and also protein manufacturing is altered and reduced making it hard for fluid to remain in the capillary blood vessels. - ECG's- p-wave: atria are depolarizing (little positive bump), q/r/s wave: ventricular depolarization (big up down wave), atrial repol is hidden, t wave: ventricular repolarization

1. Be sure to know the five core principles of physiology and be able to identify examples of each.

A. Energy needs and usage explain many structures and functions/Animals need and use energy from the environment. Ex. our bodies use food for energy, energy is in the bonds, specifically, a cell can ATP B. Structure determines function. Ex. molecules that are polar on one end and non-polar on the other, fatty acid tail, polar reacts with water (cell membrane proteins) C. Control systems integrate and regulate homeostasis is often a primary goal. Ex. regulating temp. D. Function depends on proteins encoded by genes. variation in these explains much plasticity, diversity and disease. Ex. DNA->RNA->Proteins, proteins form structure of body, and are enzymes that control processes D.1 Cells sense environment and react using electrochemical cascades that affect proteins. Ex. hormones, signaled by binding to receptor, then a transcription factor activates and effects transcription factor that binds to nuclear DNA, increasing/decreasing/stopping E. All animals share much of their physiology due to their common ancestry, but also have unique physiological adaptations.Ex. our arm bones are different than our dogs but we both have arm bones.

10. Be able to calculate partial pressures. Partial pressure = total pressure x fractional gas concentration. Understand common pulmonary pathologies including pneumothorax, asthma, hypoxia, hyperventilation, pulmonary edema and breath holding

Asthma is an obstructive disease In which expiration is impaired by decreased FVC, decreased FEV. Hypoxia is decreased oxygen delivery to the tissues and can be caused by decreased cardiac output, decreased O2 binding to hemoglobin, or decreased arterial PO2. Hyperventilation is increased breathing which can result in respiratory alkalosis (increased pH) which inhibits breathing. Edema is when the volume of interstitial fluid exceeds the capacity of lymphatics to return to the circulation and can be caused by excess filtration or blocked lymphatics. Breath holding results in an increase I PCO2 and decrease in PO2.

13. Be familiar with the anatomy of the kidneys and the pathway involved in forming filtrate (from the renal artery to the renal vein) and how it is modified along the way by secretion and reabsorption

Blood enters the kidney via the renal artery which branches into afferent arterioles which supply the glomeruli. Pressure pushes fluid between podocytes that surround the capillaries within Bowman's capsule. The filtered fluid enters the nephron

16. How can GFR be altered by hypertension, hypotension, edema, hormones, blood loss, liver disease?

Blood pressure in the glomerular capillaries - Increases filtration rate. Osmotic pressure from Bowman's capsule - Decreases filtration rate. Hydrostatic pressure from Bowman's capsule - Decreases filtration rate

Which structures are restricted, causing an asthma attack?

Bronchioles

20. What enzymes are involved, where are they produced and what is their function?

Enzymes include lipase, amylase, protease. The enzymes are released in the lumen of the GI tract through secretion (from exocrine cells by exocytosis)

9. Be familiar with cardiac output, heart rate, stroke volume and blood pressure and how they are calculated

Cardiac output = Stroke Volume x Heart Rate. Average cardiac output is between 5 and 5.5L but can be increased during exercise. Heart rate can be changed by the parasympathetic nerve system to the SA node and AV node as well as the sympathetic nerve system. See question 5. Stroke Volume = End diastolic Volume - End Systolic Volume. Stroke Volume can be changed by venous return varied by length tension ( intrinsic control) and contractility (sympathetic nerve system)

19. Be familiar with where and how mechanical and chemical digestion occurs and where nutrients and water are absorbed

Chemical digestion is a process that reduces food into its chemical building blocks which are then absorbed to nourish the cells of the body. Food molecules include proteins, lipids, nucleus acids and starches. Polymers to monomers. Mechanical digestion includes chewing and swallowing, peristaltic mixing and propulsion. Absorption and secretion occurs throughout the digestive tract, but most occurs in the small intestine. Fluid absorbed from the digestive tract goes via the hepatic portal vein to the liver first, reducing exposure to toxins or excess nutrients

The glomerular filtration rate (GFR) is one liter per min, and compound X has a plasma concentration of 2 mmol/liter. Urine production rate is 0.1 liter per min, and the concentration of compound X 30 mmol/liter. What do these data indicate?

Compound X is not reabsorbed and is also secreted.

A drug that blocks the NaCl cotransporter on the cortical collecting duct apical membrane will have what effect on urinary sodium and water loss?

Urinary sodium and water output will increase.

21. How are nutrients absorbed? Nutrients are absorbed by moving from the GI tract through epithelial cells into the interstitial fluid. Fats are absorbed by lymphatic vessels that empty into large veins near the heart. All others enter directly into capillaries that drain into veins to merge to form the hepatic portal veins which drain into the liver. What mechanisms are involved? Be familiar with pathologies such as constipation and diarrhea

Constipation is caused by distension in the rectum. The longer fecal matter remains in the large intestine, the more water is absorbed and the harder and drier the feces becomes making it difficult to dedicate and sometimes painful. A decrease in motility of the large intestine is the primary factor causing constipation. Diarrheas is a result of decreased fluid absorption, Increased fluid secretion, or both. Increased motility does not cause diarrhea but results from distinction produced by increased luminal fluid.

17. How do diuretics affect urine formation?

Diuretics reduce Na+ reabsorbtion causing more Na and water to be lost in the urine, increasing urine output. Loop diuretics block Na reabsorbtion in the ascending loop by blocking the NaCl channel. Potassium-sparing diuretics act on the cortical collecting duct , blocking aldosterone or Na+ channels on the apical membrane. Osmotic diuretics such as mannitol are filtered but not reabsorbed. As these increase osmotic pressure in the lumen, water is retained in the linen, increasing urine output.

18. What role(s) do vasopressin, atrial natriuretic peptide, and antidiuretic hormone play in regulating blood pressure? What are their mechanisms?

Each of them respond to changes the blood volume Vasopressin is an antidiuretic hormone that responds to hemorrhage or dehydration. It Increases TPR by activating V1 receptors on the arterioles and It also Increases water reabsorption by activating v2 receptors. ANP causes relaxation of vascular smooth muscles which dilate arterioles, causes increased excretion of Na+ and water by the kidney, and inhibits renin secretion. To increase BP: increase vaso, increase renin, constrict afferent/dilate efferent, decrease ANP.

2. Understand how the body adapts to high altitude. How does the body compensate for the reduced environmental oxygen?

Erythropoietin is normally secreted (by thee kidney's) in small amounts that stimulate the bone marrow to produce erythrocytes at a rate adequate to replace the usual loss. hypoxemia- peripheral chemoreceptors sense low O2, ventilation goes up, the increase Erythropoietin, travels to the bloodstream, then travels to the red bone marrow, which stimulates stem cells and developing RBC's low arterial PCO2.. gas exchange bt. alveoli and blood. hyperventilation also causes respiratory alkalosis, so your kidneys need to get rid of more HCO3 (b/c decrease arterial pCO2) The peripheral chemoreceptors stimulate ventilation. Erythropoietin, a hormone secreted primarily by the kidneys, stimulates erythrocyte synthesis—resulting in increased erythrocyte and hemoglobin concentration in blood—and the oxygen-carrying capacity of blood. DPG increases and shifts the oxygen-hemoglobin dissociation curve to the right, facilitating oxygen unloading in the tissues. However, this DPG change is not always adaptive and may be maladaptive. For example, at very high altitudes, a right shift in the curve impairs oxygen loading in the lungs, an effect that may outweigh the benefit from facilitation of unloading in the tissues. Increases in skeletal muscle capillary density (due to hypoxia-induced expression of the genes that code for angiogenic factors), number of mitochondria, and muscle myoglobin occur, all of which increase oxygen transfer. Plasma volume can be decreased, resulting in an increased concentration of erythrocytes and hemoglobin in the blood.

21. How are saltwater fish and freshwater fish similar or different with respect to salt regulation and water balance?

Freshwater fish face the problem that water tends to diffuse into them and ions tend to diffuse out. To overcome that problem, freshwater fish excrete lots of very dilute urine which eliminates excess water they gain. To overcome ion loss, they are actively absorbing ions across their gills. Saltwater fish face the opposite problem. Water tends to diffuse out and ions in. To overcome the water loss, they drink a lot of saltwater. Although they gain water, they must deal with the ions gained, most are excreted across the gills.

15. What hormones are involved in urine formation and what effect(s) do they have? How is glomerular filtration rate calculated?

GFR = Kf x net filtration pressure. Usually 115-125mL/min. GFR can be altered by plasma protein concentration, hydration level, urinalysis tract obstruction, and MAP. MAP will cause the biggest change. Increase in arterial blood pressure = increase in globular capillary blood pressure = increase in net filtration pressure = increase in GFR. Same goes for decreasing arterial blood pressure, everything will decrease. If GFR is too high, afferent arteriole vasoconstricts. If GFR is too low, afferent arteriole vasodialates.

. What mechanisms are involved in capillary gas exchange?

Gas Transport & Exchang: It occurs in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli. Steps: -ventilation by bulk flow (O2 into lungs, CO2 out) -Diffusion across res. surface -circulation of bulk flow (O2+CO2 transport via circ. system to/fro cells) -Diffusion between blood and cells (O2 diffused from blood into cells CO2 vice versa)

14. How is filtrate modified along the nephron (proximal convoluted tubules, descending limb, ascending limb, distal convoluted tubule, collecting duct)? What ion channels are involved and where are they found? What nutrients are secreted, reabsorbed, and excreted?

Glucose is reabsorbed, Na is reabsorbed, water, urea is a waste product

Understand common cardiac pathologies like hypertension and how it can be treated

Hypertension, arteriosclerosis, cardiomyopathy, and myocardial infarction are the major pathologies discussed.

17. What role does osmosis play in urine formation and what ions are involved?

In the descending limb of the loop of henle the membrane is only permeable to water, as a result, water will leave the tubule via osmosis because the concentration gradient is higher on the outside of the tubule than on the inside. As a result of water leaving, the fluid becomes more and more concentrated towards the bottom of the loop. The ascending limb is only permeable to NaCl. At the bottom of the loop, the highly concentrated fluid creates a gradient by which NaCl will passively exit the loop of henle via diffusion. As the fluid ascends up the ascending limb, then, the fluid is becoming less and less concentrated and active transport of NaCl occurs in order to resorb more salt. Where salt goes, water follows via osmosis, and in the ascending limb a lot of salt is placed outside the tubule to generate a gradient by which water will follow from the collecting ducts which are only permeable to water and its permeability is dependent upon the number of aquaporins. Water will ultimately be retained and resorbed to the blood via osmosis. The final product is relatively concentrated urine that was formed while still retaining necessary salts, ions and water needed by the body at any given time.

18. How are blood pressure and GFR related?

Increased blood volume will increase blood pressure throughout the body. The increased blood volume with its higher blood pressure will go into the afferent arteriole and into the glomerulus, resulting in increased GFR.

Increased BP

Increases in TPR, Cardiac Output, blood volume, stroke volume

Understand factors that can alter these variables. What factors regulate blood pressure?

Increases in peripheral resistance, blood volume, and cardiac output result in higher blood pressure. Conversely decreases in any of these factors lead to lower blood pressure. Three main sources of peripheral resistance: Blood vessel diameter, blood viscosity, and total vessel length.

What is the baroreceptor reflex?

The baroreceptor reflex is a negative feedback system that is responsible for the regulation of arterial blood pressure

Insects have a heart.

True

Which of the following drugs are likely to reduce blood pressure: (Select all that apply.)

a. A drug that increases sodium excretion b.A drug that blocks calcium channels on myocardial cells

Which of the following factors influence the rise in ventilation during exercise? (Select all that apply.)

a. A rise in K+ in the blood during heavy exercise b. Feedback from sensory neurons in the skeletal muscles c. Input from centers of the brain driving locomotion

Which of the following effects will occur in case of a severe pulmonary edema? (Select all that apply.)

a. Alveolar PO2 will rise b. Arterial PO2 will fall c. Alveolar PCO2 will fall d. Arterial PCO2 will rise

Which of the following are normal corrective responses of the body to hypoxia? (Select all that apply.)

a. An increase in erythropoietin increases the production of red blood cells b. A rise in ventilation c. An increase in heart rate d. An increased production of lactic acid

Choose the TRUE statement(s) about neural control of breathing. (Select all that apply.)

a. Breathing rate is modified by peripheral receptors that sense levels of oxygen in the carotid artery. b. An elevation in blood PCO2 will increase breathing rate.

Which of the following statements are likely to occur when a drug blocks beta-adrenergic receptors on the heart? (Select all that apply.)

a. Decrease heart rate b. Decrease heart contractility

Which of the following are consequences of hyperventilation?

a. Decreasing arterial PCO2 b. Higher blood pH

Select the TRUE statement(s) about saltwater fish when compared to freshwater fish. (Select all that apply.)

a. Drink more water b. Excrete more NaCl at the gill c. Urinate less

Choose the TRUE statement(s) about micturition. (Select all that apply.)

a. During the filling phase, smooth muscles in the wall of the bladder are inhibited and relaxed, but smooth muscles of the urinary sphincters are stimulated and contracting. b. During the micturition phase, the detrusor muscle is stimulated to contract by a spinal reflex via parasympathetic neurons.

What effects would a tumor that caused chronic secretion of renin expected to have? (Select all that apply.)

a. Elevated blood pressure b. Increased water and salt reabsorption by the nephron

Choose the statement that is TRUE.

a. Fat absorption from lumen to blood occurs completely by diffusion. b. Peristalsis of the stomach requires coordination of multiple motor neurons from the spinal cord. c. Histamine inhibits acid secretion by the stomach. --> d. Most digestive enzymes are produced by the pancreas.

Select the statement(s) associated with heavy exercise in high heat, with lots of sweating and no eating or drinking. (Select all that apply.)

a. High plasma levels of aldosterone b. High plasma levels of vasopressin

Which of the following will tend to increase blood flow to skeletal muscle? (Select all that apply.)

b. A rise in muscle CO2 level c. A rise in plasma epinephrine

3. Understand blood flow and how it is regulated. What factors are involved? Be familiar with the anatomy of the heart and how blood flows through the heart. What role do the valves play?

body (systemic portion) Vena cava-Right atrium-right ventricle-pulmonary artery (left and right)-pulmonary arterioles-capillary exchange -pulmonary venules - pulmonary vein-left atrium-left ventricle-(systemic now again) aorta-the body. The left side has higher oxygen content, Valves- prevent the backward flow of blood since blood goes where there is less resistance. When the AV valve closes, that corresponds to the first heart sound. Semilunar valve corresponds to the second heart sound. Flow = change pressure/rate or change pressure= rate x flow -->Also vasoconstriction and vasodilation are the major determinants that dictate blood flow, in addition to heart rate.