PNB 2265 Lecture Notes - Lecture 4: Atrioventricular Node, Stroke Volume, Isotonic Contraction
16 Aug 2018
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Document Summary
The heart is a cyclic pump, repeating the same process over and over again 2. 2 billion times during a 70 year life. This process is trigger by the cap and is designed to push blood through arteries. This cycle is examined electrically, mechanically, in terms of fluid flow and in the sounds that it makes. Changes in mechanical and electrical heart properties. Phases: 1) filling, 2) isovolumetric contraction, 3) emptying and 4) relaxation. Muscle tension applied to liquid in a closed chamber a opposite force of equal magnitude (p for pressure) Squeeze a water-filled balloon between your fingers. Water moves from an area of high to low pressure. When pressure are equal no fluid flow. Pressure is given in units of mm hg (force required to push mercury up a glass tube a certain distance) Changes in flow and pressure within the heart. Myocardial contraction increases in pressure: within both heart chambers, affects pressure within arteries.
