Question

Under normal conditions the sympathetic division is usually active in the body resting heart rates are influenced by nor epinephrine the parasympathetic system keeps heart rate lower than the heart would beat on its own. all of the above are true

Answer 1

the parasympathetic system keeps heart rate lower than the heart would beat on its own.

Step-by-step explanation:

The parasympathetic nervous system (PNS) is one division of the autonomic nervous system. The vagus (parasympathetic) nerves that innervate the heart release acetylcholine in order to slow the heart rate by decreasing the slope of the pacemaker potential. Acetylcholine activates a type of G-coupled protein receptor known as muscarinic receptors, allowing for a parasympathetic reaction in the cardiovascular system (where these receptors are expressed), and thereby decreasing cardiac output by inhibiting heart rate. During rest, PNS predominates and controls the heart rate at a resting rate of 65-80 beats/minute (bpm), if parasympathetic nerves to the heart are cut, then the heart beats at its own rate of about 100 bpm.