CARDIOVASCULAR PHYSIOLOGY

Question 1

With regard to resistance in the cardiovascular system, the parameter with the largest effect is

a) vessel length
b) radius
c) heart rate
d) viscosity
e) pressure

Answer 1

b) radius

Question 2

An increase in cardiac sympathetic activity would most likely and immediately:

a) increase stroke volume
b) decrease inotropy
c) decrease chronotropy
d) increase pulmonary pressure
e) increase angiotensin II levels

Answer 2

a) increase stroke volume

Question 3

The component of the conduction system providing the only electrical connection between the atria and the ventricles is the:

a) R wave
b) ECG
c) atrioventricular bundle
d) sinoatrial node
e) Purkinje fibres

Answer 3

c) atrioventricular bundle

Question 4

With regards to the Frank-Starling law of the heart, an increase in venous return to the heart will result in:

a) increased sympathetic activity
b) an increase in end diastolic volume
c) decreased cardiac output
d) a decrease in stroke volume
e) decreased angiotensin

Answer 4

b) an increase in end diastolic volume

Question 5

What is bradycardia?

Answer 5

Bradycardia means your heart rhythm is slow or irregular. It can cause dizziness or shortness of breath during normal activities or light exercise.

Question 6

what happens when you stimulate the vagus nerve?

Answer 6

Stimulation from the left mid-cervical vagus nerve most commonly causes voice alteration, cough, dyspnea, dysphagia, and neck pain or paresthesias. Left cervical VNS is believed to minimize potential cardiac effects such as bradycardia or asystole (primarily mediated by the right vagus nerve).

Question 7

A decrease in arterial blood pressure would most likely and immediately lead to:

a) increased afterload
b) decreased afterload
c) increased stroke volume
d) vasodilation
e) a decrease in sympathetic nerve activity

Answer 7

b) decreased afterload

Question 8

An increase in blood pressure results in:

a) decreased firing rate in the aortic baroreceptor nerve
b) increased heart rate
c) activation of chemoreceptors
d) an increase in sympathetic nerve activity
e) increased firing rate in the aortic baroreceptor nerve

Answer 8

e) increased firing rate in the aortic baroreceptor nerve

Question 9

In terms of the structural organisation of the cardiovascular system, the factor contributing most to blood pressure is:

a) angiotensin II
b) the parallel arrangement of the vascular beds
c) low resistance in the arterioles
d) the serial arrangement of the vascular beds
e) high resistance in the veins

Answer 9

b) the parallel arrangement of the vascular beds

Question 10

If acetylcholine is applied to the heart, but cardiac output is to remain constant, which of the following would have to happen?

a) Rate of conduction of impulses through the AV bundle must increase.
b) Venous return must decrease.
c) The oxygen content of blood in the coronary circulation must increase.
d) Stroke volume must increase.
e) Force of contraction must decrease.

Answer 10

d) Stroke volume must increase.

Question 11

The Frank-Starling Law of the Heart states that:

a) the absolute refractory period for the heart must be longer than the duration of contraction for efficient heart functioning.
b) cardiac output equals heart rate times stroke volume.
c) the heart is dependent upon the autonomic nervous system for a stimulus to contract.
d) a greater force of contraction can occur if the heart muscle is stretched first.
e) the heart contracts to the fullest extent possible for the conditions, or not at all.

Answer 11

d) a greater force of contraction can occur if the heart muscle is stretched first.

Question 12

On an ECG, depolarisation of the ventricles is represented by the:

a) T wave
b) QRS complex
c) P wave
d) S-T segment
e) P-Q interval

Answer 12

b) QRS complex

Question 13

On an ECG, depolarisation of the atria is represented by the:

a) P-Q interval
b) S-T segment
c) QRS complex
d) P wave
e) T wave

Answer 13

d) P wave

Question 14

If heart rate increases to very high levels, then:

a) the oxygen content of blood falls to levels insufficient to maintain cardiac activity.
b) the autonomic nervous system will release more epinephrine to the SA node to stabilise the heart rate.
c) stroke volume increases to keep cardiac output constant.
d) end-diastolic volume drops because ventricular filling time is so short.
e) end-systolic volume increases because the valves are open.

Answer 14

a) the oxygen content of blood falls to levels insufficient to maintain cardiac activity.

Question 15

The term afterload refers to:

a) end-diastolic volume.
b) the pressure in blood vessels necessary to cause the semilunar valves to close.
c) the maximum possible cardiac output above resting cardiac output.
d) end-systolic volume.
e) the pressure that must be overcome before semilunar valves can open.

Answer 15

e) the pressure that must be overcome before semilunar valves can open.

Question 16

Increased stimulation of the heart by the cardiac accelerator nerves causes:

a) stimulation by acetylcholine of muscarinic receptors on the SA node and cardiac muscle fibers of the ventricles.
b) stimulation by norepinephrine of the SA node, but no effect on the cardiac muscle fibers of the ventricles.
c) stimulation by norepinephrine of the SA node and of the alpha receptors on the cardiac muscle fibers of the ventricles.
d) stimulation by acetylcholine of nicotinic receptors on the SA node and cardiac muscle fibers of the ventricles.
e) stimulation by norepinephrine of the SA node and of the beta receptors on the cardiac muscle fibers of the ventricles.

Answer 16

e) stimulation by norepinephrine of the SA node and of the beta receptors on the cardiac muscle fibers of the ventricles.

Question 17

Stimulation of the heart by autonomic nerve fibers traveling with the vagus nerve causes:

a) decreased heart rate and no change in ventricular contractility.
b) increased heart rate and increased ventricular contractility.
c) decreased heart rate and decreased ventricular contractility.
d) decreased heart rate and increased ventricular contractility.
e) increased heart rate and no change in ventricular contractility.

Answer 17

a) decreased heart rate and no change in ventricular contractility.

Question 18

The vagus nerve

Answer 18

The Vagus Nerve is the brain’s method of controlling the parasympathetic nervous system – the rest and digest system.

Question 19

The difference between a person’s maximum cardiac output and resting cardiac output is called the:

a) stroke volume.
b) afterload.
c) cardiac reserve.
d) S-T segment.
e) preload.

Answer 19

c) cardiac reserve.

Question 20

Angina pectoris is:

a) the heart’s location within the mediastinum.
b) an embryonic structure that develops into the aorta.
c) part of the cardiac conduction system.
d) the covering of the heart.
e) pain accompanying myocardial ischemia.

Answer 20

e) pain accompanying myocardial ischemia.

Question 21

What is myocardial ischemia?

Answer 21

Myocardial ischemia occurs when blood flow to the heart muscle (myocardium) is obstructed by a partial or complete blockage of a coronary artery by a buildup of plaques (atherosclerosis). If the plaques rupture, you can have a heart attack (myocardial infarction)

Question 22

The function of baroreceptors is to monitor changes in:

a) heart rate.
b) peripheral resistance.
c) blood pressure.
d) blood viscosity.
e) stroke volume.

Answer 22

blood pressure.

Question 23

Baroreceptors are located in the:

a) walls of the capillaries.
b) wall of the right ventricle.
c) walls of the aorta and carotid arteries.
d) medulla oblongata.
e) SA node.

Answer 23

c) walls of the aorta and carotid arteries.

Question 24

The vasomotor region of the cardiovascular center directly controls:

a) stroke volume by regulating total blood volume.
b) peripheral resistance by altering blood viscosity.
c) total blood volume by regulating release of ADH from the posterior pituitary gland.
d) peripheral resistance by changing the diameter of blood vessels.
e) heart rate by stimulating the SA node.

Answer 24

d) peripheral resistance by changing the diameter of blood vessels.

Question 25

An increase in venous return most directly affects:

a) blood viscosity.
b) blood pressure.
c) systemic vascular resistance.
d) heart rate.
e) stroke volume.

Answer 25

d) heart rate

Question 26

The viscosity of blood most directly affects:

a) heart rate.
b) venous return.
c) net filtration pressure.
d) systemic vascular resistance.
e) stroke volume.

Answer 26

d) systemic vascular resistance.

Question 27

Starling’s Law of the Capillaries states that:

a) blood flows more slowly through capillaries than arteries or veins because of their smaller diameter.
b) if blood pressure is low, blood is diverted around large capillary beds.
c) the volume of fluid reabsorbed at the venous end of a capillary is nearly equal to the volume of fluid filtered out at the arterial end.
d) if oxygen levels are low, blood is diverted into large capillary beds.
e) blood pressure in capillaries equals cardiac output divided by resistance.

Answer 27

c) the volume of fluid reabsorbed at the venous end of a capillary is nearly equal to the volume of fluid filtered out at the arterial end.

Question 28

Of the pressure involved in determining net filtration pressure, the highest pressure at the venous end of a capillary is usually:

a) blood hydrostatic pressure.
b) blood colloid osmotic pressure.
c) blood hydrostatic pressure and blood colloid osmotic pressure are always equally high.
d) interstitial fluid osmotic pressure.
e) interstitial fluid hydrostatic pressure.

Answer 28

b) blood colloid osmotic pressure.

Question 29

If blood hydrostatic pressure equals 30 mm Hg, blood colloid osmotic pressure equals 26 mm Hg, interstitial fluid osmotic pressure equals 5 mm Hg, and interstitial fluid hydrostatic pressure equals 2 mm Hg, the net filtration pressure will be:

a) + 7 mm Hg.
b) - 7 mm Hg.
c) + 49 mm Hg.
d) - 1 mm Hg.
e) + 1 mm Hg.

Answer 29

a) + 7 mm Hg.

Question 30

Net filtration pressure (NFP)

Answer 30

(BHP + IFOP) - (BCOP + IFHP)

Question 31

BHP (Blood Hydrostatic pressure) + IFOP (Interstitial fluid osmotic pressure)

Answer 31

Arterial end - pressures promoting filtration - driving out oxygen glucose

Question 32

BCOP (Blood colloid osmotic pressure) + IFHP (Interstitial fluid osmotic pressure)

Answer 32

Venous end - pressures promoting reabsorption - reabsorbed waste products - pressure sucking fluid back into capillaries

Question 33

If blood hydrostatic pressure equals 30 mm Hg, blood colloid osmotic pressure equals 26 mm Hg, interstitial fluid osmotic pressure equals 5 mm Hg, and interstitial fluid hydrostatic pressure equals 2 mm Hg, the net filtration pressure will:

a) tend to filter fluids and solutes.
b) not be useful because interstitial fluid hydrostatic pressure can’t be greater than 1 mm Hg.
c) indicate no net movement of fluids or solutes.
d) tend to reabsorb fluids and solutes.
e) be impossible to calculate.

Answer 33

a) tend to filter fluids and solutes.

Question 34

If plasma proteins are lost due to kidney disease, then which of the following pressure changes occur as a direct result?

a) Interstitial fluid hydrostatic pressure decreases.
b) Blood colloid osmotic pressure decreases.
c) Blood hydrostatic pressure increases.
d) Interstitial fluid osmotic pressure decreases.
e) Blood colloid osmotic pressure increases.

Answer 34

b) Blood colloid osmotic pressure decreases.

Question 35

Blood flows most slowly through:

a) capillaries because their total cross-sectional area is the largest.
b) superior and inferior venae cavae because of their large diameters and thin walls.
c) elastic arteries because of the elastic tissue in the walls.
d) capillaries because of their small diameters.
e) superior and inferior venae cavae because of their low pressure.

Answer 35

d) capillaries because of their small diameters.

Question 36

Blood pressure would be highest in which of the following vessels?

a) inferior vena cava.
b) right subclavian vein.
c) brachiocephalic trunk.
d) blood pressure is the same in all vessels.
e) superior sagittal sinus.

Answer 36

c) brachiocephalic trunk.

Question 37

What is the brachiocephalic trunk?

Answer 37

The brachiocephalic trunk (or brachiocephalic artery or innominate artery) is an artery of the mediastinum that supplies blood to the right arm and the head and neck.

Question 38

The diameter of blood vessels most directly affects:

a) stroke volume.
b) heart rate.
c) venous return.
d) resistance.
e) blood viscosity.

Answer 38

d) resistance

Question 39

Standing still for long periods may decrease cardiac output because:

a) parasympathetic activity causes vasodilation.
b) too much lactic acid is produced, so blood vessels dilate and blood pressure drops.
c) increased blood colloid osmotic pressure allows plasma to leak into the interstitial fluid.
d) heart rate falls too low to maintain cardiac output without proprioceptive input to the cardiovascular center.
e) venous return decreases due to lack of skeletal muscle pumping of veins, so stroke volume drops.

Answer 39

e) venous return decreases due to lack of skeletal muscle pumping of veins, so stroke volume drops.

Question 40

Cardiac output refers to the

a) volume of blood ejected from the left ventricle per minute
b) heart rate multiplied by the total peripheral resistance
c) volume of blood returning to the heart
d) Starlings law of the heart
e) strength of the contraction by the left ventricle

Answer 40

a) volume of blood ejected from the left ventricle per minute

Question 41

The QRS complex of the ECG appears as the

a) atria repolarise
b) ventricles repolarise
c) atria depolarise
d) sinoatrial node depolarises
e) ventricles depolarise

Answer 41

e) ventricles depolarise

Question 42

During diastole, a chamber of the heart

a) relaxes and fills with blood
b) contracts and pushes blood into an adjacent chamber
c) reaches a pressure of approximately 120 mmHg
d) experiences a sharp increase in pressure
e) depolarises

Answer 42

a) relaxes and fills with blood

Question 43

During the cardiac cycle, the amount of blood remaining in the ventricle when the semilunar valve closes is the:

a) end-systolic volume
b) stroke volume
c) end-diastolic volume
d) cardiac output
e) ejection fraction

Answer 43

a) end-systolic volume

Question 44

Blood flow to the muscles increases if:

a) net filtration pressure increases.
b) parasympathetic stimulation to the heart increases.
c) sympathetic stimulation to venules with alpha adrenergic receptors increases.
d) vasodilation in the arterioles supplying the muscles increases.
e) blood viscosity increases.

Answer 44

d) vasodilation in the arterioles supplying the muscles increases.