Question

to increase cardiac output, the sympathetic branch of the autonomic nervous system _____ in cells of the atrioventricular node.

a. decreases the rate of rise of the HCN-induced ramp potential

b. increases cyclic AMP

c. increases ca2+released from the sarcoplasmic reticulum

d.increases activity of the CA2+ pumps in the sarcoplasmic reticulum

e.all except a is correct

Answer 1

In the cardiac output, there are 3 activities taking place in the cardiac cells as a result of the sympathetic system as per the latest research works. They are

• Elevation with respect to cyclic AMP levels along with the activation of PKA
• Increased release of calcium ions from the sarcoplasmic reticulum
• Sarcoplasmic reticulum ATPase pump or SERCA also has an enhanced activity.

These are clearly stated as option b, c and d. Therefore, the correct answer is option "E" which is a combination of all these.