Question

true or false?

When parasympathetic activity increases, there is reduced repolarization in the pacemaker cells, which decreases heart rate.

fill in

An EKG measures the electrical activity produced by__________ in the ___________.

Systolic pressure is

a. the highest pressure in the pulmonary arteries during the ventricular systolic period

b. the highest pressure in the atria during the ventricular systolic period

c. the highest pressure in the ventricles during the ventricular systolic period

d. the highest pressure in the aorta during the ventricular systolic period

Answer 1

False.

Parasympathetic activity reduces the depolarization not the repolarization. Thus heart rate is reduced as the nodal firing decreases. Nodal firing is responsible for the increase in heart rate. This is done by the release of acetylcholine.

The filing word are SA node;heart. The electrical activity is produced by the SA node which is the pacemaker cells of the heart. This makes the heart walls to contract.

Systolic pressure is the highest pressure in the aorta during the ventricular systolic period. It is the pressure experienced in the arteries mainly the aorta due to the ejection of blood from the heart by the systolic contraction