Question

52) both the left and right atria receive blood from:

53) which vessels vasoconstrict in response to epinephrine and norepinephrine?

54) which of these periods represents greatest cardiac output?

55) contraction of the heart ventricles increases pressure in the chambers causing:

56) in the average person at rest how much blood moves through the heart each min?

57) which circuit has the greatest resistance?

Answer 1

52.Atria are the upper chambers of the heart.

Left atrium receives oxygenated blood from lungs through pulmonary veins. Where as, Right atrium receives deoxygenated from superior and inferior vena cavas which is collected from the body.

53.Systemic arterioles constricts in response to the epinephrine and norepinephrine. These two hormones called catecholamine. These hormones causes contraction of smooth muscles of blood vessels.

These are the flight/fight hormones that are released when body undergo extreme stress.

54. Ventricular systole is the period re-presents greatest cardiac output.

Ventricular systole is the period of cardiac cycle when the greatest amount of blood is pumped out of the heart by ventricular contraction.

55. As the rise in intraventricular pressure causes closure of AV valves ( Atrioventricular valves) such as mitral and tricuspid valves, as intraventricular pressure is greater than the atrial pressure. Simultaneously aortic and pulmonic valves will open. Continuous rise in intraventricular pressure pumps the blood for systemic and pulmonic circulation.