Physiology Quiz
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Which of the following is true?
A. a vector that is perpendicular to the axis of the electrode causes no deflection (baseline)
B. an upward deflection on an ECG means the current flow vector is toward the negative electrode
C. a downward deflection means the current flow vector is toward the positive electrode
D. All of the answers
The hydrostatic pressure in a capillary in skeletal muscle is 37 mmHg at the arteriolar end and 14 mmHg at the venular end. The interstitial fluid hydrostatic pressure is 0 mmHg. The colloid osmotic pressure is 25 mmHg in the capillary and 1 mmHg in the interstitium. The net force producing fluid movement across the capillary wall at its arteriolar end is:
A. 13 mmHg out of the capillary
B. 13 mmHg into the capillary
C. 3 mmHg out of the capillary
D. 11 mmHg out of the capillary
E. 3 mmHg into the capillary
The rising phase of the action potential in the pacemaker cells occurs in response to:
A. activation of long-lasting, voltage-gated Ca2+ channels
B. activation of voltage-gated Na+ channels
C. activation of voltage-gated Cl channels
D. activation of transient Ca2+ channels
E. activation of voltage-gated K+ channels
Which of the following statements about coronary blood flow is the most accurate?
A. Coronary blood flow can increase 2-5 times more when compared to its resting flow
B. the heart, under resting conditions, removes up tp 25%-45% of the O2 available in the coronary
C. the myocardium receives most of its blood supply during systole, especially in the left ventricle
D. the intramyocardial pressure is the lowest in the inner layers of the ventricular wall and incresed
Which vascular bed shows almost no myogenic autoregulation:
A. none of the answers
B. cerebral circulation
C. skeletal muscle circulation
D. kidney circulation
Which statement regarding the sinoatrial node is TRUE?
A. it is innervated by the vagal nerve
B. SA node reaches threshold faster than other heart structures
C. is located in the right atrial wall near the opening of the superior vena cava
D. it does not have a stable resting potential
E. all of the answers
The heart Frank-Starling’s law depicts the relation between
A. preload and stroke volume
B. stroke volume and cardiac output
C. afterload and coronary blood flow
D. afterload and stroke volume
E. heart rate and cardiac output
The highest resting difference in arteriovenous oxygen content is a characteristic of:
A. heart
B. liver
C. lungs
D. skeletal muscles
Which of the following sets of differences best describes the hemodynamics of the pulmonary circulation when compared to the systemic circulation? (1) Flow, (2) Resistance, (3) Arterial pressure
A. (1) The same, (2) Lower, (3) Lower
B. (1) The same, (2) Higher, (3) Lower
C. (1) Lower, (2) Lower, (3) Lower
D. (1) Higher, (2) Higher, (3) Higher
An average heartbeat, or cardiac cycle, lasts approximately:
A. 0,80 seconds
B. 0,008 seconds
C. 8,0 seconds
D. 60 seconds
E. 80 seconds
Which of the following correctly describes the reactive hypermia?
A. None of the answers
B. is the process in which blood flow is increased during changes in neuronal activity in the brain
C. is the process in which blood flow is drastically increased after a blockage (obstruction)
D. is the process in which blood flow is increased during muscle contraction
E. is the process in which blood flow is constant after a blockage (obstruction)
The physiological function of the relatively slow conduction through the AV node is to allow sufficient time for:
A. filling of the ventricles
B. runoff of blood from the aorta to the arteries
C. repolarization of ventricles
D. venous return to the atria
E. contraction of ventricles
A patient got: Blood pressure = 120/80 [mmHg]; Heart rate 50 [bpm], Ejection Fraction = 60 [%], End Diastolic Volume = 150 [mL]. What is his cardiac output in [mL/min]?
A. 5500
B. 6000
C. 6500
D. 5000
E. 4500
Myogenic vascular regulation is a cellular response initiated by:
A. Stretch or tension on vascular muscle cells
B. changes in the activity of the sympathetic nervous system
C. nitric oxide release by vascular muscle cells
D. lack of oxygen in the tissue
E. an accumulation of metabolites in the tissue
In what phase of the heart contraction is the volume of blood in ventricles the GREATEST?
A. right after atrial contraction
B. right before atrial contractio
C. in the middle of ventricular ejection
D. in the middle of ventricular filling
(1) is the volume of blood contained by the ventricles at the end of an atrial contraction. And the volume of blood remaining in the ventricle when the aortic and pulmonary trunk valves close at the end of ventricular systole is known as the (2)
A. (1) end diastolic volume; (2) end systolic volume
B. (1) end diastolic volume; (2) stroke volume
C. (1) end systolic volume; (2) end diastolic volume
D. (1) stroke volume; (2) end diastolic volume
When the positive terminal is placed on the left arm and the negative terminal is placed on the right arm, the lead is known as a
A. I limb lead
B. II limb lead
C. aVR lead
D. aVF lead
E. aVL lead
Which of the following has the lowest total cross-sectional area in the body?
A. aorta
B. venules
C. capillaries
D. arterioles
E. veins
The number of action potentials per minute each type of autorhythmic cell can generate under resting conditions is as follows:
A. the rate for the SA node is 70-80, for the AV node is 40-60 and for the Bundle of His and Purkinje fiber is 20-40
B. the rate for the SA node is 70-80, for the AV node is 70-80 and for the Bundle of His and Purkinje fiber is 40-60
C. the rate for the SA node is 70-80, for the AV node is 20-40 and for the Bundle of His and Purkinje fiber is 40-60
D. the rate for the SA node is 40-60, for the AV node is 70-80 and for the Bundle of His and Purkinje fiber is 40-60
E. the rate for the SA node is 40-60, for the AV node is 70-80 and for the Bundle of His and Purkinje fiber is 20-40
The discharge of type B baroreceptors in the atria:
A. leads to an increase in heart rate
B. none of the answers
C. is increased when venous return is decreased
D. occurs primarily during atrial systole
E. all of the answers
Which of the following statements about pulmonary blood flow is most accurate?
A. During systole, the pressure in the pulmonary artery is essentially equal to the pressure in the right ventricle.
B. Blood flow through the lungs is significantly lower compared to cardiac output
C. the value of the mean pulmonary arterial pressure is about 25 mmHg
D. when the concentration of oxygen in the alveoli decreases below normal the adjacent blood vessels dilate
E. none of the answers
Consider the Einthoven’s law. The voltage measured at right arm is -0.4 mV, the left arm is +0.4 mV and the left leg is +1.0 mV. What is the value of the potential measured by the lead I:
A. positive potential of + 0.8 mV
B. positive potential of + 1.4 mV
C. positive potential of + 1.3 mV
D. negative potential of – 1.3 mV
E. negative potential of – 0.4 mV
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