Deck 12: Cardiovascular Physiology

Question 1

Which of the following is NOT primarily a function of blood plasma?

A)transport of hormones
B)being in osmotic balance with red blood cells
C)having plasma proteins that exert an osmotic pressure favoring fluid absorption into the capillaries
D)providing clotting factors that are ready to be activated
E)transport of oxygen

Answer 1

E

Question 2

Which of the following does NOT describe erythrocytes?

A)contain myoglobin
B)have a high surface-to-volume ratio
C)carry oxygen and carbon dioxide in blood
D)are red in color
E)when mature,have no nucleus

Answer 2

A

Question 3

Which of the following statements about membrane potentials in different types of cardiac cells is TRUE?

A)Myocardial cells have a resting membrane potential of about -90 mV; pacemaker cells do not have a true resting membrane potential.
B)Once threshold depolarization is reached in both myocardial and pacemaker cells,the rapid upswing of the action potential is caused by the opening of voltage-gated Na⁺ channels
C)Voltage-gated transient (T-type)Ca²⁺ channels are present in all of the different types of cells of the heart.
D)There are no L-type Ca²⁺ channels in cardiac muscle cells.
E)The upstroke of the action potential is steeper in SA node cells than it is in Purkinje cells.

Answer 3

A

Question 4

Which is TRUE about the condition anema?

A)It can be caused by too little iron in the diet.
B)It can be caused by kidney failure.
C)It can be caused by abnormal hemoglobin.
D)It results in reduced oxygen-carrying capacity of the blood.
E)All of the above are true.

Question 5

Which is correct about the contraction sequence of the heart?

A)The contraction and relaxation of of all four chambers happen at the same time.
B)The right atrium and ventricle contract at the same time,and as they are relaxing the left atrium and left ventricle begin to contract.
C)Contraction begins in this order: right atrium then right ventricle then left atrium then left ventricle.
D)The two atria contract at the same time,and as they are relaxing,the two ventricles contract together.
E)The atria and ventricles begin their contractions at the exact same time,but the atrial contraction only lasts half as long as the ventricle contraction.

Question 6

Where is most of the iron in a person's body located?

A)in the bone marrow
B)in the liver
C)in the cytochromes
D)in erythrocytes
E)in the kidneys

Question 7

Which of the following statements concerning the differences between action potentials in skeletal muscle cells and in ventricular cardiac muscle cells is TRUE?

A)Like skeletal-muscle cells,ventricular cardiac-muscle cells have a resting membrane potential closer to the sodium equilibrium potential than to the potassium equilibrium potential.
B)Unlike skeletal-muscle cells,the initial depolarization of ventricular cells is mainly due to calcium influx,not sodium influx.
C) After sodium influx through voltage-gated channels occurs in ventricular cells,a prolonged influx of calcium occurs.No such calcium influx occurs in skeletal muscle cells.
D) Action potentials in skeletal muscle cells are longer in duration than action potentials in cardiac muscle cells.
E)The efflux of K⁺ repolarizes skeletal muscle cells after an action potential,while repolarization in cardiac muscle cells is due to the efflux of Ca²⁺.

Question 8

Consider the equation F = $\Delta$ P/R. It describes the flow (F)of fluid in a tube in which there is a pressure difference ( $\Delta$ P)between the two ends and a resistance (R)to flow.Based on this equation,which is a correct conclustion?

A)The flow of fluid in a tube depends upon the absolute pressure at the beginning of the tube.
B)The rate of fluid flow in a tube will increase if the pressure at the beginning is increased while the pressure at the end of the tube stays the same.
C)The greater the resistance to flow in a tube,the greater the rate of flow for any given pressure difference.
D)If both the resistance and the pressure gradient in a tube increase,the flow must also increase.
E)The rate of flow in a tube will decrease if the resistance to flow is decreased.

Question 9

Deficiency of which of the following results in the condition,pernicious anemia?

A)iron
B)vitamin B12
C)erythropoietin
D)vitamin D
E)bilirubin

Question 10

Which of the following statements is true concerning the diastolic depolarization phase of a cell in the SA node?

A)The cell will not depolarize until it receives sympathetic stimulation.
B)The pacemaker potential is caused by Ca²⁺ entering the cell via L-type Ca²⁺ channels.
C)The pacemaker potential is slower in achieving threshold when acetylcholine is applied to the SA node cells.
D)During diastolic depolarization,there is a gradually increasing permeability to K⁺.
E)The slope of the diastolic depolarization is decreased when norepinephrine is applied to the SA node cells.

Question 11

Which of the following changes would most increase the resistance to blood flow in a blood vessel?

A)halving the diameter of the vessel
B)doubling the diameter of the vessel
C)halving the length of the vessel
D)doubling the length of the vessel
E)decreasing the hematocrit from 50% to 40%

Question 12

Action potentials in the heart spread from cell to cell through:

A)desmosomes.
B)gap junctions.
C)interneurons.
D)valves.
E)coronary vessels.

Question 13

What is the term that describes the production of red blood cells?

A)hemaglutination
B)erythrocytosis
C)erythropoiesis
D)erythroblastosis
E)hemostasis

Question 14

Which would NOT occur as a result of the blockage of action potential propagation through the bundle of His?

A)There would be a slowing of the frequency of contraction of the ventricles.
B)The atria would contract more frequently than the ventricles.
C)The SA node would no longer set the pace for atrial contraction.
D)The atria and ventricles would no longer beat in synchrony.
E) The Purkinje fibers would not receive their typical action potentials from the bundle branches.

Question 15

Which of the following would be most likely to be determined with a patient's ECG recording?

A)a heart murmur
B)stroke volume
C)cardiac output
D)blockage of conduction of electrical signals between the atria and the ventricles
E)a leaky atrioventricular valve

Question 16

What best represents the QRS complex in an electrocardiogram?

A)depolarization of the atria
B)repolarization of the atria
C)depolarization of the ventricles
D)repolarization of the ventricles
E)the delay at the AV node

Question 17

The pacemaker of the heart is normally what structure?

A)sinoatrial node
B)atrioventricular node
C)mitral valve
D)bundle of His
E)left ventricle

Question 18

A female patient has a blood test.One ml of her blood is drawn,spun in a centrifuge,and the plasma volume is measured and found to be 0.6 ml.Two months later the same patient returns to the doctor and,after doing another blood test,the doctor tells the patient that she has become anemic compared to her previous visit.Which of the following is most likely to be the woman's hematocrit on the second visit?

A)35%
B)50%
C)70%
D)100%
E)0.6 ml

Question 19

The plateau of the action potential in cardiac ventricular cells results from the opening of voltage-gated long-lasting ___________ channels in the plasma membrane of the cell.

A)Na⁺
B)K⁺
C)Ca²⁺
D)Cl^-
E) glucose

Question 20

A male patient complains of physical weakness and fatigue.A blood test shows his hematocrit to be 30%.Which of the following diagnoses is the least likely to explain his symptoms?

A)internal bleeding
B)dietary iron deficiency
C)dietary vitamin B12 deficiency
D)lung disease
E)kidney disease

Question 21

Which of the following statements about the cardiac cycle is true?

A)The duration of systole is greater than that of diastole.
B)During isovolumetric ventricular relaxation,blood flows from the atria into the ventricles.
C)Closure of the atrioventricular valves occurs at the onset of ventricular systole.
D)The QRS complex occurs at approximately the same time as the closure of the semilunar valves.
E)The first valves to go from closed to open after the atrial kick are the atrioventricular valves.

Question 22

What is indicated by a heart murmur detected between the first and second heart sounds?

A)insufficiency of a semilunar valve or stenosis of an AV valve
B)insufficiency of an AV valve or stenosis of a semilunar valve
C)heart failure
D)AV nodal conduction block
E)a myocardial infarction

Question 23

Which occurs during isovolumetric ventricular contraction?

A)Rapid filling of the ventricles occurs.
B)No blood enters or leaves the ventricles.
C)The maximum volume of blood is ejected.
D)Ventricular pressure reaches its maximum value of the cardiac cycle.
E)The pressure in the ventricles decreases while the pressure in the atria increases.

Question 24

Which of the following statements regarding the cardiac cycle is TRUE?

A)The AV valves are open during mid-to-late diastole.
B)The aortic valve is open during isovolumetric ventricular contraction.
C)The first heart sound is caused by the closing of the semilunar valves.
D)The dicrotic notch is a result of closure of the AV valves.
E)Closure of the AV valves occurs when the ventricles reach end-systolic volume.

Question 25

Which is TRUE regarding the regulation of heart rate?

A)Stimulation of parasympathetic nerves to the heart causes a slowing of heart rate.
B)Stimulation of sympathetic nerves to the heart causes an increase in heart rate.
C)A person whose heart lacks autonomic innervation has a faster heart rate at rest than a person with a normally innervated heart.
D)The slope of diastolic depolarization in SA node cell action potentials determines the heart rate.
E) All of the choices are true.

Question 26

Which of the following statements about the refractory period of neuronal or muscle membranes is TRUE?

A)In nerve cells,the absolute refractory period coincides with the period of increased K⁺ permeability.
B)In skeletal-muscle cells,the absolute refractory period lasts about as long as the twitch.
C)In ventricular cells,the absolute refractory period coincides with the period of increased Na⁺ and Ca²⁺ permeability.
D)The relative refractory period in neuronal membranes lasts about the same length of time as the absolute refractory period in cardiac muscle cell membranes.
E)The refractory period in an alpha-motor neuron membrane is much briefer than the refractory period in a skeletal muscle cell membrane.

Question 27

Which of the following statements about the absolute refractory period of cardiac muscle cells is TRUE?

A)It lasts for the same length of time in cardiac muscle cells as it does in skeletal muscle cells.
B)It is much longer than the refractory period of skeletal muscle cells.
C)It allows for tetanic contractions of the heart to occur to assure smooth,coordinated ejection of blood from the ventricles.
D) Ventricular muscle cells are in the absolute refractory period from the beginning of contraction until the beginning of their next contraction.
E)During the absolute refractory period,a larger-than-normal stimulus will result in a premature ventricular contraction.

Question 28

Which is TRUE about the comparison of excitation-contraction coupling in cardiac muscle with that in skeletal muscle?

A)Extracellular Ca²⁺ plays a major role in cardiac but not skeletal muscle.
B)The mechanism for Ca²⁺ release from the sarcoplasmic reticulum is the same in both types of muscle.
C)Troponin sites are completely saturated immediately after Ca²⁺ release in both types of muscle.
D)There is no net change in total intracellular Ca²⁺ concentration in either muscle.
E)Intracellular Ca²⁺ stores are necessary for contraction in skeletal muscle,but not in cardiac muscle.

Question 29

According to the Frank-Starling mechanism of the heart:

A)the left ventricle ejects a larger volume of blood with each systole than the right ventricle.
B)the intrinsic rate of the heart's pacemaker is 100 beats/min.
C)cardiac output increases with increased heart rate.
D)stroke volume increases with increased venous return.
E)both ventricles contract simultaneously.

Question 30

The frequency of action potentials generated by the SA node is:

A)increased by parasympathetic stimulation.
B)decreased by sympathetic stimulation.
C)increased by acetylcholine.
D)increased by epinephrine.
E)increased by an increase in blood pressure.

Question 31

What causes the opening and closing of the heart valves?

A)stimulation by the sympathetic and parasympathetic nerves
B)a pressure difference on the two sides of the valve
C)Na⁺ and K⁺ fluxes during ventricular depolarization
D)turbulent flow in the atria and ventricles
E)the action of the papillary muscles and chordae tendineae

Question 32

During the cardiac cycle:

A)the volume of blood leaving the left side of the heart is greater than that leaving the right side.
B)the pressure of blood leaving the right ventricle is greater than that leaving the left ventricle.
C)the duration of systole is greater than that of diastole.
D)the duration of diastole is greater than that of systole.
E)the contraction of the atria overlaps in time with with ventricular systole.

Question 33

Which of the following statements about blood vessel structure and function is FALSE?

A)Veins are more compliant than arteries.
B)The aorta and other large arteries serve as a pressure reservoir for the circulatory system.
C)Arterioles are small vessels whose resistance to blood flow can be varied.
D)Arterioles,capillaries,and veins all have valves that allow only one-way flow of blood.
E)If your blood pressure is 100/70 your mean arterial blood pressure is ~80 mm Hg

Question 34

Which of these best describes active hyperemia?

A)increased metabolic activity that results in vasoconstriction
B)increased metabolic activity that results in vasodilation
C)decreased blood flow to tissues that results in vasoconstriction
D)decreased blood flow to tissues that results in vasodilation
E)increased blood pressure that drives blood more rapidly through tissues

Question 35

Which of the following statements concerning regulation of blood flow is TRUE?

A)Increased levels of metabolic waste products and decreased oxygen concentration in tissues promote hyperemia through the tissues.
B)If blood flow to a tissue is blocked for a period of time and then the block is removed,the result is a reactive hyperemia in which blood flow through the affected tissue remains low.
C)According to flow autoregulation,if blood pressure to an arteriole is decreased,blood flow will not return toward its original level until the original blood pressure is restored.
D)High levels of CO2 and metabolites tend to cause contraction in the smooth muscle of arteriole walls.
E)The resistance to blood flow in brain and heart vascular beds does not vary in response to changes in local gas or metabolite concentrations.

Question 36

Which is TRUE about the function of the aortic valve?

A)It prevents the backflow of blood into the aorta during ventricular diastole.
B)It prevents the backflow of blood into the left ventricle during ventricular diastole.
C)It prevents the backflow of blood into the left ventricle during ventricular ejection.
D)It prevents the backflow of blood into the aorta during ventricular ejection.
E)Its closure causes the first heart sound.

Question 37

Which best defines the cardiac output?

A)the end-diastolic volume minus the end-systolic volume
B)the output of the aortic arch baroreceptors
C)the volume of blood in the arterial tree at any moment in time
D)the stroke volume divided by the heart rate
E)the product of the heart rate and the volume ejected from the ventricle during a cardiac cycle

Question 38

Sinoatrial node cells:

A)reach threshold only when action potentials generated by the AV node arrive through gap junctions.
B)exhibit spontaneous depolarization that is speeded by activation of their cholinergic receptors.
C)exhibit spontaneous depolarization that is speeded by activation of their beta-adrenergic receptors.
D)exhibit a steep upstroke due to the presence of the same type of Na⁺ channels found in neuronal membranes.
E)are in-between atrial muscle cells and cells of the bundle of His.

Question 39

Which of the following is NOT an effect of sympathetic stimulation of the heart?

A)an increase in heart rate
B)a decrease in the duration of systole
C)a decrease in the slope of the pacemaker potential
D)an increase in the amount of Ca²⁺ entering cardiac muscle cells
E)an increase in the rate of cross-bridge cycling in ventricular muscle cells

Question 40

What is described by the Frank-Starling mechanism of the heart?

A) the relationship between end-diastolic volume and heart rate
B)the relationship between end-systolic volume and stroke volume
C)the relationship between length and tension in cardiac muscle cells
D)the relationship between sympathetic stimulation and stroke volume
E)the relationship between arterial blood pressure and stroke volume

Question 41

Which of the following is most likely to be a cause of hypotension?

A)an increase in blood volume
B)sweating,vomiting,or emotional responses
C)decreased firing of the arterial baroreceptors
D)increased release of epinephrine by the adrenal medulla
E)a sudden decrease in firing of the parasympathetic nervous system

Question 42

Which of the following does NOT contribute to increased stroke volume during exercise?

A)increased contractility of cardiac muscle
B)increased venous return
C)increased length of filling time during diastole
D)increased sympathetic stimulation of ventricular muscle
E)increased end-diastolic volume

Question 43

Which of the following statements concerning control of blood flow through arterioles is TRUE?

A)Beta-adrenergic receptors are more abundant on most arteriolar smooth muscle than are alpha-adrenergic receptors.
B)Binding of epinephrine to alpha-adrenergic receptors causes vasodilation.
C)Increased stimulation of vascular smooth muscle by the parasympathetic nervous system causes increased vasoconstriction.
D)If the arterial blood pressure to an organ suddenly decreases,arterioles in the organ will dilate in response.
E)Body-wide constriction of arterioles results in a decrease in the total peripheral resistance (TPR).

Question 44

Normally,the hydrostatic pressure difference between capillary fluid and interstitial fluid favors movement of fluid ________ a tissue capillary.The protein osmotic pressure difference between capillary fluid and interstitial fluid normally favors movement of fluid __________ a tissue capillary.

A)into; into
B)into; out of
C)out of; out of
D)out of; into

Question 45

Distinguishing characteristics of veins include which of the following?

A)All veins carry deoxygenated blood.
B)All veins carry blood toward the heart.
C)All veins have thick,elastic walls.
D)Veins have walls consisting only of endothelial cells.
E)All veins have valves to ensure one-way movement of blood.

Question 46

Which of the following factors would NOT tend to increase systemic arterial blood pressure?

A)increased sympathetic stimulation of the blood vessels
B)increased blood volume
C)increased venous return
D)increased parasympathetic stimulation of the heart
E)increased activity of the skeletal muscle pump

Question 47

Which of the following is a result of increased sympathetic stimulation of vascular smooth muscle?

A)Filtration of fluid from capillaries to interstitial fluid increases.
B)Total peripheral resistance (TPR)decreases.
C)The percentage of blood volume in the veins increases.
D)Blood flow to the brain decreases.
E)Venous return of blood to the heart increases.

Question 48

Which of the following correctly compares the factors involved in bulk flow of fluid in systemic and pulmonary capillaries?

A)The protein oncotic pressure inside pulmonary capillaries is significantly greater.
B)There are no lymphatic vessels to remove fluid from lung interstitial fluid.
C)The hydrostatic pressure inside pulmonary capillaries is significantly lower.
D)The protein oncotic pressure is lower in pulmonary interstitial fluid than in typical systemic interstitial fluid.
E)The Starling's forces overwhelmingly favor reabsorption all along the length of pulmonary capillaries.

Question 49

Which is the most likely effect of physical endurance training on a person's cardiac performance?

A)a decrease in cardiac output
B)an increase in maximal stroke volume
C)an increase in maximal heart rate
D)an increase in resting heart rate
E)an increase in cardiac output when the person is at rest

Question 50

Blood flow through most organs is regulated primarily by increasing or decreasing the ________ activity to arteriolar smooth muscles in the organ.Another form of regulation,called ________,depends upon the metabolic activity of the organ.Increased activity leads to increased interstitial-fluid metabolites,which cause ________ of the arterioles.The former is a type of ________ regulation of blood flow; the latter is an example of ________ regulation.

A)sympathetic; active hyperemia; dilation; extrinsic; intrinsic
B)sympathetic; reactive hyperemia; dilation; intrinsic; extrinsic
C)parasympathetic; active hyperemia; constriction; extrinsic; intrinsic
D)sympathetic; flow autoregulation; constriction; intrinsic; extrinsic
E)parasympathetic; reactive hyperemia; dilation; extrinsic; intrinsic

Question 51

What determines the movement of blood in systemic veins?

A)The blood pressure difference between systemic capillaries and the right atrium.
B)The contraction and relaxation of skeletal muscles.
C)The decrease of thoracic pressure and increase of abdominal pressure due to diaphragm movement.
D)Valves in the veins.
E)All of the above.

Question 52

Jane donates a pint of blood to a blood bank.A few minutes later,which of the following would be decreased compared to pre-donation values?

A)her stroke volume and total peripheral resistance
B)her heart rate and total peripheral resistance
C)her heart rate and mean arterial pressure
D)the percentage of her cardiac output flowing to her kidneys
E)blood flow to her brain

Question 53

Jane donates a pint of blood to a blood bank.A few minutes later,which of the following would be increased compared to pre-donation values?

A)her stroke volume and total peripheral resistance
B)her heart rate and total peripheral resistance
C)her heart rate and mean arterial pressure
D)the percentage of her cardiac output flowing to her kidneys
E)the blood flow to her brain

Question 54

Which is a typical response of the body to hemorrhage?

A)decreasing the heart rate below normal
B)decreasing total peripheral resistance to below normal levels
C)raising mean arterial pressure to above normal
D)increasing cardiac output to above normal levels
E)increasing bulk flow reabsorption of fluid into capillaries

Question 55

Which of the following statements concerning the capillaries is FALSE?

A)Increasing capillary hydrostatic pressure decreases the likelihood that filtration will occur.
B)Velocity of blood flow is slower in the capillaries than in the arteries.
C)It is possible for a capillary to filter fluid at its arterial end and absorb fluid at its venous end.
D)Large capillary pores are more likely to be found in liver capillaries than in brain capillaries.
E)Large proteins that escape capillaries and enter the interstitial fluid are returned to the circulation via the lymphatic system.

Question 56

If the arterial blood pressure in the brain is suddenly decreased,the flow through arterioles in the brain will immediately fall and then which of these will occur next?

A)Brain arterioles will constrict to accelerate blood flow through the brain capillaries.
B)Brain arterioles will dilate due to a decrease in levels of CO2.
C)Blood flow will remain at the new,lower level due to reactive hyperemia.
D)Blood flow will rise to levels above normal due to excess O2 levels.
E)Blood flow will return toward its original level due to flow autoregulation.

Question 57

Following hemorrhage,reflexes are triggered that attempt to compensate for the blood loss.As a result of the blood loss and the reflex mechanisms,which of the following will be true,compared to prehemorrhage values?

A)Both cardiac output and total peripheral resistance will be increased.
B)Both cardiac output and total peripheral resistance will be decreased.
C)Cardiac output will be increased and total peripheral resistance will be decreased.
D)Cardiac output will be decreased and total peripheral resistance will be increased.
E)Hematocrit will be increased.

Question 58

During exercise,there is a decreased flow of blood to:

A)the brain.
B)the skin.
C)the abdominal organs.
D)the skeletal muscles
E)the heart.

Question 59

How would a hemorrhage immediately affect the activity of the baroreceptors?

A)The baroreceptors would increase their rate of firing to all medullary cardiovascular center cell types.
B)The baroreceptors would increase their rate of firing to cells in the medulla oblongata that activate sympathetic pathways and decrease their rate of firing to cells in the medulla oblongata that activate parasympathetic pathways.
C)The baroreceptors would decrease their rate of firing to all medullary cardiovascular center cell types.
D)The baroreceptors would decrease their rate of firing to cells in the medulla oblongata that activate sympathetic pathways and increase their rate of firing to cells in the medulla oblongata that activate parasympathetic pathways.
E)A hemorrhage would not affect the activity of the baroreceptors.

Question 60

Which of the following is most likely to occur when a soldier stands at attention--very still,with legs and spine straight?

A)decreased pressure in the capillaries of the feet
B)increased absorption of interstitial fluid by the capillaries of the feet
C)increased storage of blood in the veins of the feet and legs
D)increased venous return
E)increased blood flow to the brain

Question 61

Which of the following is NOT an anticoagulant or stimulator of blood clot dissolution?

A)vitamin K
B)aspirin
C)thrombin
D)heparin
E)tissue plasminogen activator (t-PA)

Question 62

At rest,more blood flows per minute to the kidneys and abdominal organs than to the muscles and skin.

Question 63

Arterial systolic pressure occurs ____________________ while arterial diastolic pressure occurs_____________________.

A)at the same time as closure of the semilunar valves; at the same time as closure of the atrioventricular valves
B)during the isovolumetric contraction phase of the cardiac cycle; during the isovolumetric relaxation phase of the cardiac cycle
C)at the same time as the P-wave of the electrocardiogram; at the same time as the T-wave of the electrocardiogram
D)when the the ventricle reaches end-systolic volume; when the ventricle reaches end-diastolic volume
E)during the middle of the phase of ventricular ejection; just before the semilunar valve opens

Question 64

Atherosclerosis is:

A)the major cause of heart attacks.
B)a thinning in the walls of arteries.
C)associated with low blood levels of cholesterol and heavy exercise.
D)a disease in which the walls of arteries become more compliant.
E)more common in younger people than in older people.

Question 65

Which of the following is NOT likely to result in edema?

A)blockage of lymph vessels
B)prolonged standing
C)liver disease
D)heart failure
E)elevated plasma protein concentrations

Question 66

Which of the following statements regarding blood clotting is TRUE?

A)Blood clotting requires activation of thrombin.
B)Blood clotting is enhanced by prostaglandin I₂ (PGI₂)and nitric oxide.
C)A blood clot is a network of interlacing strands of fibrinogen.
D)Blood clotting occurs too rapidly in indivduals with the disease hemophilia.
E)Injecting tissue plasminogen activator (t-PA)into a patient who is bleeding will aid blood clotting.

Question 67

Blood loss is likely to stimulate the secretion of higher than normal plasma levels of erythropoietin.

Question 68

At rest,more blood flows to the skin and abdominal organs than to the lungs.

Question 69

All blood vessels that carry well-oxygenated blood are called arteries.

Question 70

Platelets participate in hemostasis by:

A)aggregating to form a plug and manufacturing fibrinogen.
B)secreting nitric oxide and releasing chemicals that promote vasoconstriction.
C)secreting prostacyclin,which prevents platelet aggregation on blood vessel endothelium.
D)aggregating to form a plug and releasing chemicals that promote vasoconstriction.
E)secreting tissue plasminogen activator (t-PA)whenever they come into contact with collagen.

Question 71

The primary stimulus for erythropoietin secretion is decreased iron concentrations in the liver.

Question 72

Which is an intermediary protein that enables platelets to adhere to collagen?

A)tissue plasminogen activator (t-PA)
B)ATP
C)von Willebrand factor (vWF)
D)arachidonic acid
E)activated protein C

Question 73

Which of these correctly states differences between a trained athlete and a sedentary individual at rest?

A) The athlete would have a lower heart rate and larger stroke volume.
B) The athlete would have a higher heart rate and larger stroke volume.
C) The athlete would have a lower heart rate and smaller stroke volume.
D) The athlete would have a higher heart rate and smaller stroke volume.
E) There would be no differences when the individuals were at rest.

Question 74

What is hemostasis?

A)the maintenance of relatively stable conditions in the internal environment
B)the prevention or stoppage of blood loss
C)a disease in which blood clot formation is impaired
D)a protein inside red blood cells that binds oxygen with high affinity
E)the set point for normal arterial blood pressure

Question 75

Which of the following occurs first in hemostasis?

A)activation of the fibrinolytic system
B)platelet aggregation
C)a clotting cascade that leads to the conversion of fibrinogen to stable fibrin
D)conversion of prothrombin to thrombin
E)conversion of plasminogen to plasmin

Question 76

Which of the following does not describe hypertension? Hypertension

A) refers to a chronic state of elevated blood pressure.
B) is usually defined as a systolic pressure greater than 140 mm Hg and a diastolic pressure greater than 90 mm Hg.
C) is usually a result of chronically elevated cardiac output.
D) may be caused by kidney disease.
E) can sometimes be treated with drugs that increase excretion of water in the urine.

Question 77

Which of the following drugs might be prescribed to alleviate hypertension?

A)an alpha-adrenergic receptor agonist
B)a beta-adrenergic receptor antagonist
C)a cholinergic antagonist
D)a drug that increases L-type Ca²⁺ channel currents
E)a drug that increases T-type Ca²⁺ channel currents

Question 78

Which of the following statements about blood clotting is NOT true?

A)It is the formation of a thrombus.
B)It occurs after formation of a platelet plug in a damaged vessel.
C)It requires the presence of erythrocytes.
D)It is a result of a cascade of enzyme activation.
E)It involves positive feedback by thrombin.

Question 79

Which correctly describes functions of Protein C?

A)It activates platelets and converts prothrombin to thrombin.
B)It activates clotting factor XII and platelets.
C) It binds to tissue factor and activates clotting factor VII.
D)It inactivates thrombin and converts fibrinogen to fibrin.
E)It inhibits clot formation and inactivates factors Va and VIIIa.

Question 80

Which of the following statements regarding the dissolving of blood clots is FALSE?

A)Activation of the reactions that lead to blood clotting ultimately lead to blood clot dissolution.
B)Tissue plasminogen activator (t-PA)is secreted by endothelial cells.
C)Blood clots are digested by plasmin.
D)Plasminogen is an inactive precursor of the enzyme plasmin.
E)It involves aggregation of soluble fibrin fragments into fibrin.