Deck 12: Cardiovascular Physiology

Question 1

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

A)Sodium
B)Potassium
C)Calcium
D)Chloride
E)Glucose

Answer 1

C

Question 2

If action potential propagation through the bundle of His were blocked,which of the following events would you expect to occur?

A)There would be a slowing of the rate 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)Both there would be a slowing of the rate of contraction of the ventricles and the atria would contract more frequently than the ventricles would occur
E)All of these things would occur

Answer 2

E

Question 3

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

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 sodium channels
C)Voltage-gated calcium channels are opened at some time during the action potential in both myocardial and pacemaker cells
D)Both myocardial cells have a resting membrane potential of about -90 mV; pacemaker cells do not have a true resting membrane potential and 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 sodium channels are correct
E)Both myocardial cells have a resting membrane potential of about -90 mV; pacemaker cells do not have a true resting membrane potential and voltage-gated calcium channels are opened at some time during the action potential in both myocardial and pacemaker cells are correct

Answer 3

D

Question 4

The pacemaker of the heart is normally the

A)Sinoatrial node
B)Atrioventricular node
C)Mitral valve
D)Bundle of His
E)Left ventricle

Question 5

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 fast channels occurs in ventricular cells, an influx of calcium occurs.No such calcium influx occurs after sodium influx in the skeletal-muscle cells
D)Action potentials in skeletal-muscle cells are longer in duration than action potentials in cardiac cells
E)All of the choices are true

Question 6

Consider the equation F = DP/R. It describes the flow (F)of fluid in a tube in which there is a pressure difference (DP)between the two ends and a resistance (R)to flow.The equation indicates that

A)The flow of fluid in a tube depends upon the absolute pressure at the beginning of the tube
B)The flow of fluid from point A to point B in a tube depends upon the difference in pressure between A and B
C)The greater the resistance to flow in a tube, the greater the flow for any given pressure difference
D)Both the flow of fluid in a tube depends upon the absolute pressure at the beginning of the tube and the greater the resistance to flow in a tube, the greater the flow for any given pressure difference are correct
E)Both the flow of fluid from point A to point B in a tube depends upon the difference in pressure between A and B and the greater the resistance to flow in a tube, the greater the flow for any given pressure difference are correct

Question 7

The process of erythrocyte production is called

A)Hemaglutination
B)Erythrocytosis
C)Erythropoiesis
D)Erythroblastosis
E)Hemostasis

Question 8

An ECG would be useful for determining a patient's

A)Heart murmur
B)Stroke volume
C)Cardiac output
D)Blockage of conduction of electrical signals between the atria and the ventricles
E)None of the choices are correct

Question 9

Dietary requirements for optimal erythrocyte production and function include

A)Iron
B)Vitamin B12
C)Erythropoietin
D)Iron and vitamin B12
E)All of these things

Question 10

Cardiac and smooth muscle share some characteristics,including

A)Desmosomes
B)Gap junctions
C)Pacemaker capability in some cells
D)Gap junctions and pacemaker capability in some cells
E)All of these things

Question 11

Which of the following does not describe erythrocytes? They

A)Contain myoglobin
B)Have a high surface-to-volume ratio
C)Carry oxygen and carbon dioxide in blood
D)Are red
E)Have no nucleus

Question 12

Which of the following criteria must be met for the heart to function efficiently?

A)Excitation and the consequent contraction of the cardiac muscle fibers of each heart chamber should be coordinated to assure efficient pumping
B)The atria should be excited and contract before the onset of ventricular contraction to assure that ventricular filling is complete
C)The right side of the heart should contract first to assure that oxygenated blood is delivered to the heart before the left side contracts
D)Both excitation and the consequent contraction of the cardiac muscle fibers of each heart chamber should be coordinated to assure efficient pumping and the atria should be excited and contract before the onset of ventricular contraction to assure that ventricular filling is complete are correct
E)All of the choices are correct

Question 13

In an electrocardiogram,the QRS complex represents the

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 14

Most of the iron in a person's body is

A)Stored in the bone marrow
B)Stored in the liver
C)Found in the cytochromes
D)Found in erythrocytes
E)Excreted daily

Question 15

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 16

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 17

Anemia

A)Can be caused by too little iron in the diet
B)Can be caused by kidney failure
C)Can be caused by abnormal hemoglobin
D)Refers to reduced oxygen-carrying capacity of the blood
E)Is described by all of these choices

Question 18

Which of the following statements is true concerning the depolarization 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 calcium entering the cell via slow channels
C)The pacemaker potential is slower in achieving threshold when acetylcholine is applied to the SA cells
D)Both the pacemaker potential is caused by calcium entering the cell via slow channels and the pacemaker potential is slower in achieving threshold when acetylcholine is applied to the SA cells are correct
E)None of the choices are true

Question 19

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

A)Transport of hormones
B)Maintaining the size of red blood cells
C)Providing protein osmotic pressure favoring fluid absorption in the capillaries
D)Providing clotting factors that are ready to be activated
E)Transport of oxygen

Question 20

A male patient complains of physical weakness and fatigue.A blood test shows his hematocrit to be 35%.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

The discharge rate of the SA node is

A)Increased by parasympathetic stimulation
B)Decreased by sympathetic stimulation
C)Increased by acetylcholine
D)Increased by epinephrine
E)None of the choices are correct

Question 22

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 23

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

A)It increases heart rate
B)It decreases the duration of systole
C)It decreases the slope of the pacemaker potential
D)It increases the amount of calcium ion entering cardiac cells
E)It increases the rate of cross-bridge cycling in ventricular cells

Question 24

Sinoatrial node cells

A)Are normally the pacemakers of the heart
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)Both are normally the pacemakers of the heart and exhibit spontaneous depolarization that is speeded by activation of their cholinergic receptors are correct
E)Both are normally the pacemakers of the heart and exhibit spontaneous depolarization that is speeded by activation of their beta-adrenergic receptors are correct

Question 25

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 systole
D)Both the duration of systole is greater than that of diastole and during isovolumetric ventricular relaxation, blood flows from the atria into the ventricles are true
E)Both during isovolumetric ventricular relaxation, blood flows from the atria into the ventricles and closure of the atrioventricular valves occurs at the onset of systole are true

Question 26

A heart murmur that is detected between the first and second heart sounds is indicative of

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)Heart block
E)A myocardial infarction

Question 27

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

A)It lasts almost as long as the resultant period of contraction of the 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)Both it lasts almost as long as the resultant period of contraction of the cells and it is much longer than the refractory period of skeletal muscle cells are true
E)All of the choices are true

Question 28

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 29

The heart valves open and close due to

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)None of the choices are correct

Question 30

Comparing excitation-contraction coupling in cardiac muscle with that in skeletal muscle:

A)Extracellular calcium plays a major role in cardiac but not skeletal muscle
B)The stimulus for calcium release from the sarcoplasmic reticulum is the same in both muscles
C)Troponin sites are always saturated immediately after calcium release in both muscles
D)There is no net change in total intracellular calcium concentration in either muscle
E)Both extracellular calcium plays a major role in cardiac but not skeletal muscle and the stimulus for calcium release from the sarcoplasmic reticulum is the same in both muscles are correct

Question 31

Cardiac output is the

A)Volume of blood pumped per minute by both ventricles
B)Volume of blood flowing through the systemic circulation each minute
C)Product of the number of heartbeats per minute and the volume pumped per beat
D)Both volume of blood pumped per minute by both ventricles and product of the number of heartbeats per minute and the volume pumped per beat are correct
E)Both volume of blood flowing through the systemic circulation each minute and product of the number of heartbeats per minute and the volume pumped per beat are correct

Question 32

With regard to 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)Both stimulation of parasympathetic nerves to the heart causes a slowing of heart rate and stimulation of sympathetic nerves to the heart causes an increase in heart rate are true
E)All of the choices are true

Question 33

The Frank-Starling mechanism of the heart describes

A)The relationship between end-diastolic volume and heart rate
B)The relationship between end-diastolic volume and stroke volume
C)The relationship between length and tension in cardiac muscle
D)The relationship between end-diastolic volume and heart rate and the relationship between length and tension in cardiac muscle
E)The relationship between end-diastolic volume and stroke volume and the relationship between length and tension in cardiac muscle

Question 34

The aortic valve

A)Prevents the backflow of blood into the aorta during ventricular diastole
B)Prevents the backflow of blood into the left ventricle during ventricular diastole
C)Prevents the backflow of blood into the left ventricle during ventricular ejection
D)Prevents the backflow of blood into the aorta during ventricular ejection
E)Closes when the first heart sound is heard

Question 35

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 is at a maximum
E)None of these things would occur

Question 36

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)Both increased levels of metabolic waste products and decreased oxygen concentration in tissues promote hyperemia through the tissues and 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 are true
E)Both increased levels of metabolic waste products and decreased oxygen concentration in tissues promote hyperemia through the tissues and 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 are true

Question 37

Active hyperemia refers to

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)None of the choices are correct

Question 38

Which of the following statements about the refractory period of nerve or muscle membranes is correct?

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 almost as long as the twitch
C)In ventricular cells, the absolute refractory period coincides with the period of increased Na⁺ and Ca2⁺ permeability
D)Both in nerve cells, the absolute refractory period coincides with the period of increased K⁺ permeability and in skeletal-muscle cells, the absolute refractory period lasts almost as long as the twitch are correct
E)Both in skeletal-muscle cells, the absolute refractory period lasts almost as long as the twitch and in ventricular cells, the absolute refractory period coincides with the period of increased Na⁺and Ca2⁺ permeability are correct

Question 39

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

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 the closing of the semilunar valves
D)Both the AV valves are open during mid-to-late diastole and the aortic valve is open during isovolumetric ventricular contraction are correct
E)Both the AV valves are open during mid-to-late diastole and the first heart sound is the closing of the semilunar valves are correct

Question 40

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 side of the heart is greater than that leaving the left side
C)The duration of systole is greater than that of diastole
D)The duration of diastole is greater than that of systole
E)Both the volume of blood leaving the left side of the heart is greater than that leaving the right side and the duration of diastole is greater than that of systole occur

Question 41

Movement of blood in veins is determined by

A)The blood pressure difference between veins and atria
B)The skeletal pump
C)The decrease of thoracic pressure and increase of abdominal pressure due to diaphragm movement
D)Valves in the veins
E)All of the choices are correct

Question 42

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 43

If the arterial blood pressure in the brain is suddenly decreased,the flow through arterioles in the brain will immediately fall and then return to near their original levels due to flow autoregulation.

A)This statement is false.The arterioles of the brain do not exhibit flow autoregulation to any significant extent
B)This statement is false.The flow of blood will only rise
C)This statement is false.The flow of blood will only fall
D)This statement is false.The flow of blood will not change
E)This statement is true

Question 44

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 at its arterial end and absorb at its venous end
D)Discontinuous endothelium is more likely to be found in liver capillaries than in brain capillaries
E)Large proteins that enter the interstitial fluid are returned to the circulation via the lymphatic system

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)Both all veins carry deoxygenated blood and all veins carry blood toward the heart are correct
E)Both all veins carry blood toward the heart and all veins have thick, elastic walls are correct

Question 46

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 47

During exercise,there is an increased flow of blood to

A)The brain
B)The kidneys
C)The skin
D)The kidneys and the skin
E)All of the choices are correct

Question 48

Jane donates a pint of blood to a blood bank.A few minutes later,which of the following would be increased compared to its/their 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 49

Hypotension

A)Refers to blood loss
B)Can be caused by sweating, vomiting, or emotional responses
C)Stimulates increased firing of the arterial baroreceptors
D)Both refers to blood loss and stimulates increased firing of the arterial baroreceptors are correct
E)Both can be caused by sweating, vomiting, or emotional responses and stimulates increased firing of the arterial baroreceptors are correct

Question 50

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

A)The baroreceptors would decrease their rate of firing.This would cause vasodilation and a decrease in cardiac output, which together would decrease blood pressure
B)The baroreceptors would increase their rate of firing.This would cause vasoconstriction and an increase in cardiac output, which together would increase blood pressure
C)The baroreceptors would decrease their rate of firing.This would cause vasoconstriction and an increase in cardiac output, which together would increase blood pressure
D)The baroreceptors would increase their rate of firing.This would cause vasodilation and a decrease in cardiac output, which together would decrease blood pressure
E)The baroreceptors would decrease their rate of firing.This would cause vasodilation and an increase in cardiac output, which together would decrease blood pressure

Question 51

Which of the following would a soldier standing very still,at attention,likely experience?

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)All of the choices are correct

Question 52

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)All of the choices are true

Question 53

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

A)Filtration in capillaries increases
B)Total arteriolar diameter increases
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 54

Normally,the hydrostatic pressure difference between capillary fluid and interstitial fluid favors movement of fluid (into/out of)the capillary.The osmotic pressure difference between capillary fluid and interstitial fluid favors movement of fluid (into/out of)the capillary.

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

Question 55

Jane donates a pint of blood to a blood bank.A few minutes later,which of the following would be decreased compared to its/their 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 56

Which of the following factors would not tend to increase blood pressure directly?

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 57

Physical endurance training enhances a person's

A)Maximal cardiac output
B)Maximal stroke volume
C)Maximal heart rate
D)Both maximal cardiac output and maximal stroke volume are correct
E)All of the choices are correct

Question 58

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 59

Capillary exchange is somewhat different in the pulmonary capillaries and produces interstitial fluids which have a higher accumulation of proteins than in other areas of the body because

A)Pulmonary circulation is low resistance
B)The pulmonary circuit is a low pressure circuit
C)The pulmonary capillary hydrostatic pressures in this area is lower than at other locations
D)The Starling forces present in the lungs, favor filtration
E)All of the choices are true

Question 60

The body responds to hemorrhage by

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)Keeping mean arterial pressure to levels approaching but below normal

Question 61

Traditionally,a "normal" blood pressure is considered to be 120 systolic/80 diastolic,but presently new guidelines suggest that medical interventions should be initiated for treating hypertension at systolic pressures of ____ and diastolic pressures of _____.

A)130-139, 85-89
B)140-154, 90-95
C)155-160, 96-101
D)110-119, 70-79
E)Actually this is determined by individual physicians without regard to accepted norms

Question 62

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

Question 63

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

A)Activation of the reactions that lead to blood clotting ultimately lead to blood clot dissolution
B)Blood clot dissolution requires activation of thrombin
C)Blood clots are digested by plasmin
D)Both activation of the reactions that lead to blood clotting ultimately lead to blood clot dissolution and blood clot dissolution requires activation of thrombin are true
E)All of the choices are true

Question 64

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 65

An anemic person is likely to have higher than normal plasma levels of erythropoietin.

Question 66

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

Question 67

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)Both an alpha-adrenergic receptor agonist and a cholinergic antagonist are correct
E)Both a beta-adrenergic receptor antagonist and a cholinergic antagonist are correct

Question 68

Platelet aggregation is

A)The first step in the formation of a platelet plug
B)Stimulated by ATP
C)Stimulated by von Willebrand factor
D)Stimulated by the conversion of arachidonic acid in platelet plasma membranes to prostacyclin
E)Described by none of these choices

Question 69

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

Question 70

Which of the following statements regarding blood clotting is true?

A)Blood clotting requires activation of thrombin
B)Blood clotting is the result of a cascade of enzyme activation
C)A blood clot is a network of interlacing strands of fibrinogen
D)Both blood clotting requires activation of thrombin and blood clotting is the result of a cascade of enzyme activation are true
E)All of the choices are true

Question 71

Deep Check
Which of the drug treatments listed below is mismatched to its mode of action in treating hypertension?

A)Alpha-adrenergic receptor blockers - reduce TPR by decreased stimulation
B)of arteriolar smooth muscle
C)Antagonists of parasympathetic receptors - reduce TPR by decreased
D)stimulation of arteriolar smooth muscle
E)Diuretics - increase excretion of sodium and water in urine

Question 72

Platelets participate in hemostasis by

A)Aggregating to form a plug
B)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)All of the choices are correct

Question 73

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 74

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 75

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

Question 76

Hemostasis

A)Is the maintenance of relatively stable conditions in the internal environment
B)Refers to the prevention or stoppage of blood loss
C)Is dependent upon platelet aggregation
D)Both is the maintenance of relatively stable conditions in the internal environment and refers to the prevention or stoppage of blood loss are correct
E)Both refers to the prevention or stoppage of blood loss and is dependent upon platelet aggregation are correct

Question 77

Protein C

A)Is present in active form at all times in the blood plasma
B)Inhibits clot formation
C)Inactivates factors Va and VIIIa
D)Inactivates thrombin
E)Both inhibits clot formation and inactivates factors Va and VIIIa are correct

Question 78

A trained athlete differs from a "couch potato" in that the athlete has

A)A lower heart rate at rest
B)A higher heart rate at rest
C)Greater stroke volume at maximal effort
D)A lower heart rate at rest and greater stroke volume at maximal effort
E)A higher heart rate at rest and greater stroke volume at maximal effort

Question 79

Which of the following statements about blood clotting is not true? Blood clotting

A)Is the formation of a thrombus
B)Occurs after formation of a platelet plug in a damaged vessel
C)Requires the presence of erythrocytes
D)Is a result of a cascade of enzyme activation
E)Is an example of positive feedback

Question 80

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)The major cause of heart attacks and is associated with low blood levels of cholesterol and heavy exercise
E)All of the choices are correct