Cardiovascular System Essay

370 WordsOct 6, 20112 Pages
A physiological control system is defined as a device which monitors and adjusts key function of regulated variable to maintain homeostasis (Silverthorne Pg. 7). Any control system has three parts: an input signal, a controller and an output signal. In physiological control system, changes in range of the regulated variable works as input signal, controller act as integrating center and output signal will be normal desirable range of regulated variables to maintain the homeostasis. In cardiovascular system, heart works as pump to maintain blood flow and blood pressure in human body. The main physiological control system for this action of heart is cardiovascular physiological control system. The input signal for this function of heart is blood flow to the heart. The heart’s cardiac muscle fiber will react as controller by contracting forcefully or minimal to the significance blood flow which enters in the system. The output signal will be the blood pressure generated by the contraction. The blood flow in cardiovascular system requires a pressure gradient, because blood flow from region of higher pressure to region of lower pressure (Silverthorne pg. 471). Arteries are considered as pressure reservoir and veins are considered as volume reservoir. As blood flow through the closed circulatory system, it will lose the pressure as it goes far away from the heart because of friction between fluid and the vessel wall. The pressure in the veins is really lower especially in vena cava before they empty the blood in the right atrium. The myocardial cells get the input signal for contraction from the autorhythmic cells, which set the rate of the heart beat. One of the factors that affect the force of contraction at the beginning of cardiac muscle contraction is the length of the sacromere. Which means longer the muscle fiber and sacromere when contraction begins, the

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