38 Questions
Which of the following statements about the composition of faeces is true?
30 per cent of the solid matter is represented by dead bacteria
Which statement accurately represents the role of aldosterone?
Aldosterone enhances sodium transport capability
Which event of the cardiac cycle correlates with rapid inflow?
Diastasis
What causes the odour of faeces?
Skatole is an odoriferous product
Which statement is true about the absorption of chloride ions in the large intestine?
The mucosa of the large intestine absorbs chloride ions in an exchange transport process
What does the white colour of faeces indicate?
The white colour of faeces is caused by the presence of urobilin in the faeces
Which of the following statements about heart muscle energy metabolism is correct?
Approximately 70 to 90 percent of heart muscle energy is normally derived from oxidative metabolism of fatty acids.
Which statement accurately describes the effect of temperature on the heart's contractile strength?
Prolonged elevation of temperature exhausts the metabolic systems of the heart and eventually causes spastic contraction.
Which statement accurately describes the role of calcium ions in cardiac muscle contraction?
Without the calcium from the T tubules, the strength of cardiac muscle contraction would be reduced considerably.
Which statement accurately describes the effects of sympathetic stimulation on the heart and vessels?
Bronchodilation (β2 adrenergic receptors)
Which statement accurately describes events of the cardiac cycle for left ventricular function?
After opening of the aortic valve, the intraventricular volume rapidly increases
Which of the following correctly represents the events of the cardiac cycle for left ventricular function?
C: Aortic valve closes, Isovolumic relaxation, open A-V valves
Which curve on the volume-pressure diagram represents ventricular pressure?
B: Ventricular volume
Which statement about the heart's composition and function is correct?
C: Each atrium is a weak primer pump for the ventricle.
What occurs during phase 0 (depolarization) of the cardiac muscle action potential?
D: Fast sodium channels open.
Which event occurs during Period H on the volume-pressure diagram?
A: Isovolumetric relaxation
What represents the end diastolic volume on the volume-pressure diagram?
A: V3: stroke volume (120-50=70 mL)
Which statement correctly describes the ejection fraction?
The ejection fraction is usually equal to about 0.6 (or 60 percent).
What happens to the pressure in the aorta after opening the aortic valve?
Increasing after opening aortic valve
When does the pressure in the left ventricle increase slightly?
Increasing after closing the mitral valve
When does the aortic valve close?
Closes after atrial contraction
What happens to the aortic pressure at the end of systole?
After the left ventricle stops ejecting blood and the aortic valve closes, the aortic pressure suddenly drops to diastolic pressure.
Which statement is correct regarding the strength of contraction of cardiac muscle?
The strength of contraction depends to a great extent on the concentration of calcium ions in the extracellular fluids
Which statement is correct about the pressure curve in the atria?
The atrial contraction usually causes an additional 20 percent filling of the ventricles
Which statement accurately describes the ejection of blood from the ventricles?
The first third of ejection is called the period of isovolumetric contraction
Which statement accurately describes the function of A-V valves and semilunar valves?
The semilunar valves prevent backflow from the aorta and pulmonary arteries into the ventricles during diastole
Which statement accurately describes the electrocardiogram (ECG) waves?
The P wave is caused by spread of depolarization through the atria
Which statement correctly describes the phases of cardiac muscle action potential?
Phase 3 (rapid repolarization) sees calcium channels open and slow potassium channels close
During which phase does the intraventricular pressure rapidly increase?
After opening of the aortic valve
Which structure brings depolarization from the S-A node?
E: S-A node
What is the interval of time needed to pass from S-A node to atrial contractile myocardium?
$0.3$ seconds
What is the intrinsic discharge rate of the A-V nodal fibers?
40 to 60 times per minute
Where are the rhythmical impulses of the heart normally generated?
In the sinus node
What causes the self-excitation of sinus nodal fibers?
The inward-leaking Na+ and Ca2+ overbalance the K+ outflow
What is the effect of hyperpolarization on sinus nodal cells?
What could continue throughout a person’s life in sinus nodal fibers?
Rhythmical discharge
Where are Purkinje fibers located in relation to the heart?
$I: Ventricular septum$
What happens if the conductive system of the heart stops?
$0.16$’’ delay before ventricles contract
Test your knowledge of cardiac physiology with this quiz! Answer questions on topics such as ejection fraction, stroke volume, ventricular volumes, and electrical depolarization of the ventricles.
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