During the isovolumetric contraction phase of ventricular sy

During the isovolumetric contraction phase of ventricular systole, the A) atria are contracting and the ventricles are relaxing B) atrioventricular valves and semilunar valves are closed. C) blood ois ejected into the great vessels. D) All of the answers are correct. E) None of the answers is correct. Pacemaker cells isolated from the SA node generate action potentials at___ beats per minute A) 20-40 B) 40-60 C) 90-100 D) 100-140 E) 140-110 The long plateau phase of the cardiac muscle action potential la due to a) movement of fewer sodium ions across the cell membrane into the cell. B) calcium channels remaining open. C) increased membrane permeability to potassium ion. D) decrease in the amount of calcium diffusing across the membrane E) increased membrane permeability to sodium ions As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit A) tonus B) treppe C) tetany D) recruitment E) fatigue.

Solution

Hi,

Answer of 15 is

(b)atrioventricular valves and semiluner valves are closed.

Answer of 16 is

(B)pacemaker cells isolated from SA node generate action potential at 80-100 beats per minute.

Answer of 17 is

(B)calcium cannel remaining open.

Answer of 18 is

(C)As a results of long refractory period in cardiac action potential cardiac muscle cannot exhibit tetany.

I hope my answers are satisfactory.

Thanks!!