CVC MCQ

Question 1

The major mechanism controlling coronary artery diameter is:

accumulation of metabolic waste products.

Answer 1

a

Question 2

According to Fick’s law, which ONE of the following would NOT be a factor in diffusion of a substance across the capillary wall?

Hydrostatic (blood) pressure in the capillary

Answer 2

a

Question 3

A patient absorbs 300ml/min of oxygen. The oxygen content of blood taken from the femoral artery = 18ml/100ml and blood taken from the pulmonary artery has an oxygen content of 13ml/100ml. If the patient has a heart rate of 60 beats/min, the patient’s stroke volume is:

100ml.

Answer 3

A

Question 4

Which ONE of the following organs/tissues receives the greatest increase in systemic blood flow during exercise?

Muscle

Answer 4

a

Question 5

During which phase of the cardiac cycle are all four heart valves open?

all four heart valves are normally never open simultaneously

Answer 5

a

Question 6

Which ONE choice indicates three events that occur at about the same time during the cardiac cycle?

**A-V valve closure, first heart sound, ventricular systole.

Answer 6

a

Question 7

Which ONE of the following is true of the ventricular filling phase of the cardiac cycle?

**Ventricular pressure is less than aortic pressure.

Answer 7

a

Question 8

Key mechanisms in combating orthostatic or postural hypotension include:

all of the above.
(reduced distensibility of leg veins compared to thoracic veins, the baroreceptor reflex, muscle pumps)

Answer 8

a

Question 9

Unlike blood vessels, the lymphatic system:

reabsorbs protein and foreign particles from the interstitial fluid.

Answer 9

a

Question 10

Blood that leaves the right ventricle and later enters the left ventricle must have passed through which of the following valves?

Pulmonary and bicuspid/mitral valves.

Answer 10

a

Question 11

Which ONE of the following statements regarding blood vessels is INCORRECT?

Capillaries contain smooth muscle in their walls.

Answer 11

a

Question 12

The major mechanism controlling the diameter of arteries in the skin is:

sympathetic nerve activity

Answer 12

a

Question 13

Which ONE of the following parameters, when increased, will cause an increase in cardiac stroke volume?

**end-diastolic volume (EDV)

Answer 13

a

Question 14

Which ONE of the following statements regarding blood vessels is INCORRECT?

The pressure in venules would be less than the pressure in large veins.

Answer 14

a

Question 15

**The repolarisation of pacemaker cells is due in part to:

**an increase in the permeability of potassium.

Answer 15

a

Question 16

Myocardial contractility

is increased by adrenaline

Answer 16

a

Question 17

**In cardiac muscle, the action potential in the ventricles:

**relies on an increase in calcium permeability.

Answer 17

Q

Question 18

Myogenic mechanisms involved in autoregulation of blood flow are activated by:

altered intra-luminal blood pressure.

Answer 18

Q

Question 19

The greatest proportion of blood volume is present within which ONE of the following vessel types?

Systemic veins and venules

Answer 19

A

Question 20

The major mechanism(s) controlling the diameter of arteries in the skeletal muscle is

all of the above

(extracellular CO2 concentration, extracellular K+ concentration, accumulation of metabolic waste products, myogenic mechanisms)

Answer 20

A

Question 21

What is occurring during ventricular ejection?

**The AV valves are closed and the semilunar valves are open as blood is leaving the ventricles.

Answer 21

a

Question 22

Compared to sinoatrial cells, ventricular contractile cells will have:

A more negative resting membrane potential

Answer 22

a

Question 23

Which ONE of the following would NOT result in an increase in the movement of fluid out of capillaries?

A decrease in the osmotic pressure of the interstitial fluid.

Answer 23

a

Question 24

Which ONE of the following statements is INCORRECT? Increased sympathetic nervous system activity to the sinoatrial node:

decreases the slope of the spontaneous depolarisation of these action potentials.

Answer 24

a

Question 25

**Stimulation of the heart by sympathetic nerves **causes tachycardia

Answer 25

a

Question 26

**Stimulation of the heart by parasympathetic nerves **causes bradycardia

Answer 26

a

Question 27

Pre-load is equivalent to **Ventricular end-diastolic volume (EDV)

Answer 27

a

Question 28

According to Poiseuille’s equation, blood flow in a vessel would be reduced by half when: vessel length is doubled.

Answer 28

a

Question 29

According to Poiseuille’s equation, reducing a blood vessel’s diameter by 20% would reduce blood flow in the vessel by (approximately): 60%

Answer 29

a

Question 30

Which ONE of the following is responsible for the rapid depolarization phase of an action potential within the pacemaker cells? **An increase in PCa2+

Answer 30

a

Question 31

Closure of the aortic valve is associated with all of the following except: rapid filling of the left ventricle.

Answer 31

a

Question 32

The volume reflex, in which heart rate and renal blood flow are increased following an increase in blood volume, is mediated primarily by: atrial and vena cava baroreceptors

Answer 32

a

Question 33

**Blood flow velocity is slowest in ______ because this is where ______ is greatest. capillaries, cross-sectional area

Answer 33

a

Question 34

During the rapid ejection phase of the cardiac cycle, which ONE of the following statements is INCORRECT? The ventricular volume is at its lowest.

Answer 34

a

Question 35

Which ONE of the following is INCORRECT regarding the mechanism by which the substance moves across the wall of a capillary? Glucose is carried across the wall by plasma filtration.

Answer 35

a

Question 36

**The decrease in blood pressure is greatest across ______ because this is where ______ is highest. **arterioles, resistance

Answer 36

a

Question 37

Which ONE of the following statements about the conduction system of the heart is INCORRECT? Electrical events can spread directly between atria and ventricles through gap junctions.

Answer 37

a

Question 38

The firing rate of aortic baroreceptors is increased by increased blood pressure.

Answer 38

a

Question 39

Starling’s Law of the Heart means that when ventricular pre-load is increased, stroke volume will increase

Answer 39

a

Question 40

A reflex increase in heart rate may be caused by: all of the above. (a decrease in peripheral resistance, an increase in venous return, a decrease in arterial blood pressure, an increase in right atrial pressure)

Answer 40

a

Question 41

An increase in myocardial contractility will result in: **decreased end-systolic volume and increased stroke volume.

Answer 41

a

Question 42

Cardiac stroke volume may be defined as **end-diastolic volume (EDV) minus end-systolic volume (ESV)

Answer 42

a

Question 43

Which ONE of the following statements about an action potential generated from a sinus nodal fibre is INCORRECT? *The unstable baseline can be partly attributable to a progressive decrease in Ca2+ permeability.

Answer 43

a

Question 44

Which ONE of the following statements about an action potential generated from a non-pacemaker cardiac cell is INCORRECT? Repolarisation occurs as a result of inactivation of K+ channels.

Answer 44

a

Question 45

If systemic blood pressure falls, the carotid baroreceptors would cause heart rate to ______ and peripheral ________. Increase, vasoconstriction

Answer 45

a

Question 46

According to the Starling Equation, which ONE of the following would NOT be a factor in the net filtration pressure controlling the movement of water across the capillary wall? The number and size of the pores in the capillary wall.

Answer 46

a

Question 47

The function of the papillary muscles and chordae tendinae is to: Keep the AV valves from bulging into the atria during ventricular contraction.

Answer 47

a