Discuss the chronotropic effects of the sympathetic and parasympathetic nervous systems on the heart
What will be an ideal response?
The sympathetic nervous system releases a neurotransmitter, norepinephrine, which has a positive chronotropic effect on the heart. Due to the influence of the sympathetic nervous system, the sinoatrial (SA) node fires more quickly and the calcium ion concentration in the cardiac muscle cells increases. Both effects increase stroke volume, heart rate, and cardiac output. The parasympathetic nervous system releases a neurotransmitter, acetylcholine, from the vagus nerves (CN X). Acetylcholine has a negative chronotropic effect on the heart by slowing the rate of the sinoatrial (SA) node. Thus, heart rate and cardiac output decreases.
You might also like to view...
All parts of herbs have equal potency and effectiveness
a. true b. false
Dissection of human bodies became part of formal medical school coursework in
the ______ century. Fill in the blank(s) with correct word
Which of the following is NOT true of the resting membrane potential?
A. The membrane is freely permeable to sodium ions. B. Large, negatively charged proteins are inside the cell. C. Potassium ions are concentrated inside the cell. D. Sodium ions are concentrated outside the cell.
Which skull canal does the internal carotid artery pass through?
A. Carotid canal B. Nasolacrimal canal C. External auditory canal D. Foramen ovale E. Jugular foramen