Physiology 1021 Lecture Notes - Lecture 6: Circulatory System, Blood Vessel, Closed System
19 Apr 2017
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General function, organization, and anatomy of circulation: the principle functions of the cardio system: Systemic circulation: total blood volume (tbv) = 5 liters. Ivc/svc ra rav valve rv. Lungs la lav valve lv aortic valve aorta. Cardiac function: there are 2 types of myocardial cells, contractile cells (do the contracting, specialized nodal and conducting cells (signaling contractile cells to contract, similarities between skeletal and cardiac muscle. Contain similar contractile proteins (actin & myosin) 1/3 of volume is occupied by mitochondria (to produce atp) Extracts 80% of the oxygen from the blood. Joined by intercalated discs that contain gap junctions and desmosomes: gap junctions allow movement of ionic currents (aps) between cells, nodal and conducting cells. It is the site of fastest spontaneous generation of the ap: sa node is the (cid:862)pa(cid:272)e(cid:373)aker(cid:863) of the heart. ** both of these characteristics cause the sa nodal cells to spontaneously depolarize to threshold*: sa nodal action potential, pacemaker potential a slow depolarization caused by:
