KNES 260 Study Guide - Midterm Guide: Pulmonary Circulation, Mitral Valve, Pulmonary Artery
26 Feb 2017
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Purpose: ensures that blood flow through the heart in one direction preventing backflow. Valve problems (heart murmurs): stenosis: narrowing of the heart valve. Will hear whistling when valve should be open: valve insufficiency: blood regurgitation (ie. into atria from ventricle) Decreased forward ejection due to faulty closing. Will hear whirring when valve should be closed. Purpose: auto-rhythmic (pacemaker cells): initiating and conducting action potentials, contractile (myocardial cells): form the majority of the heart; flexible fibres that are able to shorten or lengthen in order to contract. Parts of the conducting pathway: sinoatrial node (sa): mass of auto-rhythmic cells located on the superior wall of the right atrium. Known as the pacemaker (as it sets the pace for heart contractions) 100 ms) which allows ventricles to contract after the atria have: bundle of his: collection of cells that transmit the impulse from av node to the apex.
