CVC MCQ Flashcards
The major mechanism controlling coronary artery diameter is:
accumulation of metabolic waste products.
a
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
a
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.
A
Which ONE of the following organs/tissues receives the greatest increase in systemic blood flow during exercise?
Muscle
a
During which phase of the cardiac cycle are all four heart valves open?
all four heart valves are normally never open simultaneously
a
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.
a
Which ONE of the following is true of the ventricular filling phase of the cardiac cycle?
**Ventricular pressure is less than aortic pressure.
a
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)
a
Unlike blood vessels, the lymphatic system:
reabsorbs protein and foreign particles from the interstitial fluid.
a
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.
a
Which ONE of the following statements regarding blood vessels is INCORRECT?
Capillaries contain smooth muscle in their walls.
a
The major mechanism controlling the diameter of arteries in the skin is:
sympathetic nerve activity
a
Which ONE of the following parameters, when increased, will cause an increase in cardiac stroke volume?
**end-diastolic volume (EDV)
a
Which ONE of the following statements regarding blood vessels is INCORRECT?
The pressure in venules would be less than the pressure in large veins.
a
**The repolarisation of pacemaker cells is due in part to:
**an increase in the permeability of potassium.
a
Myocardial contractility
is increased by adrenaline
a
**In cardiac muscle, the action potential in the ventricles:
**relies on an increase in calcium permeability.
Q
Myogenic mechanisms involved in autoregulation of blood flow are activated by:
altered intra-luminal blood pressure.
Q
The greatest proportion of blood volume is present within which ONE of the following vessel types?
Systemic veins and venules
A
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)
A
What is occurring during ventricular ejection?
**The AV valves are closed and the semilunar valves are open as blood is leaving the ventricles.
a
Compared to sinoatrial cells, ventricular contractile cells will have:
A more negative resting membrane potential
a
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.
a
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.
a
**Stimulation of the heart by sympathetic nerves
**causes tachycardia
a
**Stimulation of the heart by parasympathetic nerves
**causes bradycardia
a
Pre-load is equivalent to
**Ventricular end-diastolic volume (EDV)
a
According to Poiseuille’s equation, blood flow in a vessel would be reduced by half when:
vessel length is doubled.
a
According to Poiseuille’s equation, reducing a blood vessel’s diameter by 20% would reduce blood flow in the vessel by (approximately):
60%
a
Which ONE of the following is responsible for the rapid depolarization phase of an action potential within the pacemaker cells?
**An increase in PCa2+
a
Closure of the aortic valve is associated with all of the following except:
rapid filling of the left ventricle.
a
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
a
**Blood flow velocity is slowest in ______ because this is where ______ is greatest.
capillaries, cross-sectional area
a
During the rapid ejection phase of the cardiac cycle, which ONE of the following statements is INCORRECT?
The ventricular volume is at its lowest.
a
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.
a
**The decrease in blood pressure is greatest across ______ because this is where ______ is highest.
**arterioles, resistance
a
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.
a
The firing rate of aortic baroreceptors is increased by
increased blood pressure.
a
Starling’s Law of the Heart means that when ventricular pre-load is increased, stroke volume will
increase
a
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)
a
An increase in myocardial contractility will result in:
**decreased end-systolic volume and increased stroke volume.
a
Cardiac stroke volume may be defined as
**end-diastolic volume (EDV) minus end-systolic volume (ESV)
a
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.
a
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.
a
If systemic blood pressure falls, the carotid baroreceptors would cause heart rate to ______ and peripheral ________.
Increase, vasoconstriction
a
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.
a
The function of the papillary muscles and chordae tendinae is to:
Keep the AV valves from bulging into the atria during ventricular contraction.
a
