Lab 4 - Human Cardiovascular

Increase sympathetic nerve activity decrease diameter

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Unformatted text preview: enous pressure and increase venous return as more blood is returned to the heart. Increase Increase venous volume increase venous pressure Increase venous capacitance decrease venous pressure Sympathetic Nervous System & Bl Blood Pressure Mean Mean Arterial Pressure (MAP) MAP is the average pressure that drives blood through the the systemic organs. MAP = 1/3 (SP) + 2/3 (DP) Not simply an average of the two pressures because the heart heart spends more time in diastole than it does in systole (at rest). Blood Blood Pressure Measurement Sphygmomanometer – inflatable cuff and measuring unit to restrict blood flow and measure pressure Compression of Brachial Artery Sympathetic Nervous System (SNS) – can change arteriolar resistance and venous capacitance Greatly influence blood pressure Norepinephrine released from these nerves binds to 1 th bi adrenergic receptors on the smooth muscle cells and on causes vasoconstriction In the arterioles, this results in an increase in resistance, which decreases blood flow to the venous si d e id On the venous side, vasoconstriction leads to a decrease in capacitance which decreases venous decrease in capacitance, which decreases venous volume volume Venous constriction plays a major role in increasing blood blood return to the heart Total Peripheral Resistance (TPR) TPR the overall resistance to flow TPR – the overall resistance to flow through through the systemic cardiovascular system system Can be calculated if MAP and CO ar...
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This document was uploaded on 01/13/2014.

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