KINE 1P90 Lecture Notes - Lecture 7: Vasospasm, Threshold Potential, Homeostasis

• School: Brock University
• Department: Physical Education and Kinesiology
• Course: KINE 1P90
• Professor: Klentrou Panagiota

Document Summary

One complete sequence of contraction and relaxation of the heart (all 4 chambers) During the cardiac cycle, the pressure within the chambers rises and falls. Atrial systole - contraction of the atria (we don"t call it contraction, its systole or depolarization - no difference between meanings) When the atria are relaxed, blood flows into (and through) them. When the atria contract, the pressure in the atria rises forcing blood into the ventricles. As the ventricles contract (systole), the bicuspid and tricuspid valves close, and blood flows out of the ventricles into the arteries. The bicuspid and tricuspid valves open, and blood flows from the atria to the ventricles. Ventricles fill with blood from the contracting atria. Ventricles start to contract and pressure builds in ventricles (isovolumetric contraction) bicuspid and tricuspid valves close. Semilunar valves are forced open and blood flow from ventricles into arteries. Ventricles relax with bicuspid and tricuspid valves still closed (isovolumetric relaxation)