PHYL2001 Study Guide - Final Guide: Pericardium, Heart Valve, Qrs Complex
Document Summary
Atrial systole adds more blood to ventricles. When pressure rises, there is no change in volume. Heart relaxes, volume doesn"t change for awhile. Isovolumic contraction of ventricles occur when all heart valves closed at start of systole. During relaxation, isovolumic phase also occur when all heart valves close. In ecg: when p wave happens, triggers atrial contraction. R wave: pressure in v rises rapidly = rst heart sound. Starts lling blood because of change in pressure. Ejection doesn"t start until pressure in ventricles higher than arteries. Apex: pointy bit of ventricle (upside down pyramid) Spreads from apex, up (starts squeezing at apex, then up the ventricles) -> so that can push blood to the greater vessels. Av delay to allow atrial contraction to nish before ventricular systole begins. Most myocardial cells will contract without any form of input by hormones.
