BIO-0014 Lecture Notes - Lecture 23: Sinoatrial Node, Inferior Vena Cava, Mediastinum
25 Apr 2017
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Document Summary
Potential energy is the main type of energy in pushing blood around the circuitry. In order to overcome frictional resistance, potential energy is used up. Therefore the heart must be energized continuously: if blood stops bleeding no blood flow, death with follow. Allows us to divert the blood where we may not need as much to areas we need it more: happens during exercise, through the skeletal muscles. The blood goes down a vascular tree that is mostly a branching or parallel circuit and not a series circuit. During exercise blood vessels dilate in exercising tissues (i. e. skeletal muscles) and constrict in non-exercising tissues (e. g. The capillaries are quite small, but there are many many of them: total cross sectional area is quite high, due to branching circuitry. Velocity is distance per time (cm/sec: flow is volume per time, velocity = flow/area.
