ANP 1105 Study Guide - Final Guide: Medulla Oblongata, Atrioventricular Node, Pacemaker Potential

• School: University of Ottawa
• Department: Anatomy and Physiology
• Course: ANP 1105
• Professor: Joanna Komorowski

Document Summary

Heartbeat is modified by the ans: cardiac centers are located in the medulla oblongata of the brain stem. Cardioacceleratory center innervates sa and av nodes, heart muscle, and coronary arteries through sympathetic neurons. Cardioinhibitory center inhibits sa and av nodes through parasympathetic fibers in the vagus. Depressor area - decreases bp by inhibi ng nervescausing vasoconstric on. Increaseshr(isac vated when the pressor area is s mulated) Cardioinhibitory center - depressesheart ac vity(is associated with vagusnerve) Heart rate at rest: a prepotential or pacemaker potential in a heart at rest. Heart rate under parasympathetic stimulation: decreased heart rate resulting when ach released by parasympathetic neurons opens chemically gated k+ channels, thereby slowing the rate of spontaneous depolarization. Increased heart rate resulting when ne released by sympathetic neurons leads to the opening of ion channels,increases the rate of depolarization and shortens the period of repolarization. Electrocardiograph = ecg = ekg = a graphic record of electrical activity of the heart.