Cardiac Physiology Quiz

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Which of the following statements about the composition of faeces is true?

The white colour of the faces is caused by the presence of urobilin in the faeces

30 per cent of the solid matter is represented by dead bacteria (correct)

10 to 20 per cent of the solid matter is represented by fat

The odour of faeces is caused by derivatives of bilirubin

Which statement accurately represents the role of aldosterone?

The mucosa of the large intestine absorbs chloride ions in an exchange transport process

More than 10 mEq of sodium ions are lost in the faeces

Aldosterone enhances sodium transport capability (correct)

The storage colon is represented by the distal half of the colon

Which event of the cardiac cycle correlates with rapid inflow?

Ejection

Diastasis (correct)

Isovolumic relaxation

Isovolumic contraction

What causes the odour of faeces?

Skatole is an odoriferous product Signup and view all the answers

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 Signup and view all the answers

What does the white colour of faeces indicate?

The white colour of faeces is caused by the presence of urobilin in the faeces Signup and view all the answers

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. Signup and view all the answers

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. Signup and view all the answers

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. Signup and view all the answers

Which statement accurately describes the effects of sympathetic stimulation on the heart and vessels?

Bronchodilation (β2 adrenergic receptors) Signup and view all the answers

Which statement accurately describes events of the cardiac cycle for left ventricular function?

After opening of the aortic valve, the intraventricular volume rapidly increases Signup and view all the answers

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 Signup and view all the answers

Which curve on the volume-pressure diagram represents ventricular pressure?

B: Ventricular volume Signup and view all the answers

Which statement about the heart's composition and function is correct?

C: Each atrium is a weak primer pump for the ventricle. Signup and view all the answers

What occurs during phase 0 (depolarization) of the cardiac muscle action potential?

D: Fast sodium channels open. Signup and view all the answers

Which event occurs during Period H on the volume-pressure diagram?

A: Isovolumetric relaxation Signup and view all the answers

What represents the end diastolic volume on the volume-pressure diagram?

A: V3: stroke volume (120-50=70 mL) Signup and view all the answers

Which statement correctly describes the ejection fraction?

The ejection fraction is usually equal to about 0.6 (or 60 percent). Signup and view all the answers

What happens to the pressure in the aorta after opening the aortic valve?

Increasing after opening aortic valve Signup and view all the answers

When does the pressure in the left ventricle increase slightly?

Increasing after closing the mitral valve Signup and view all the answers

When does the aortic valve close?

Closes after atrial contraction Signup and view all the answers

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. Signup and view all the answers

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 Signup and view all the answers

Which statement is correct about the pressure curve in the atria?

The atrial contraction usually causes an additional 20 percent filling of the ventricles Signup and view all the answers

Which statement accurately describes the ejection of blood from the ventricles?

The first third of ejection is called the period of isovolumetric contraction Signup and view all the answers

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 Signup and view all the answers

Which statement accurately describes the electrocardiogram (ECG) waves?

The P wave is caused by spread of depolarization through the atria Signup and view all the answers

Which statement correctly describes the phases of cardiac muscle action potential?

Phase 3 (rapid repolarization) sees calcium channels open and slow potassium channels close Signup and view all the answers

During which phase does the intraventricular pressure rapidly increase?

After opening of the aortic valve Signup and view all the answers

Which structure brings depolarization from the S-A node?

E: S-A node Signup and view all the answers

What is the interval of time needed to pass from S-A node to atrial contractile myocardium?

$0.3$ seconds Signup and view all the answers

What is the intrinsic discharge rate of the A-V nodal fibers?

40 to 60 times per minute Signup and view all the answers

Where are the rhythmical impulses of the heart normally generated?

In the sinus node Signup and view all the answers

What causes the self-excitation of sinus nodal fibers?

The inward-leaking Na+ and Ca2+ overbalance the K+ outflow Signup and view all the answers

What is the effect of hyperpolarization on sinus nodal cells?

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What could continue throughout a person’s life in sinus nodal fibers?

Rhythmical discharge Signup and view all the answers

Where are Purkinje fibers located in relation to the heart?

$I: Ventricular septum$ Signup and view all the answers

What happens if the conductive system of the heart stops?

$0.16$’’ delay before ventricles contract Signup and view all the answers