Phystut12 - Cardiovascular III(cont Andrew MacDonald Click...

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Click to edit Master subtitle style 2/28/10 Cardiovascular III (con’t) Andrew MacDonald [email protected]
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2/28/10 Neural Mechanisms – ANS control Parasympathetic Nervous System Small indirect effect on the blood vessels, it will cause slight vasodilation. Sympathetic Nervous System Releases norepinephrine (epinephrine from adrenal gland) which causes a general vasoconstriction. Acetylcholine released onto Fight or flight! Relaxatio n
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2/28/10 Neural Mechanisms – Baroreceptor Reflex The Barorecptor Reflex is a negative feedback system. The Barorecptor Reflex regulates the mean arterial pressure (MAP) . MAP = Diastolic Pressure + 1/3 (systolic – diastolic) It is an indication of the blood pressure in the body. How does the baroreceptor reflex attenuate the mean arterial pressure? Regulating the 1) Cardiac Output. Regulation the 2) Total Peripheral Resistance. (mostly the resistance encountered in the arterioles)
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2/28/10 Baroreceptor Reflex (2) Remember the equation. Blood Flow = (Pressure Change) / (Resistance) Throughout the entire body the C.O. also is equal too… Cardiac Output = (MAP) / TPR) Therefore, MAP ( mean arterial pressure) = (C.O.) X (TPR) This provides further evidence to the fact that both the cardiac output (stroke volume x heart rate) and the total peripherial resistance (TPR, vasodilation and vasoconstriction) are the
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2/28/10 Baroreceptor Reflex (3) MAP = (C.O.) X (TPR) The cardiovascular control centre is located in the brainstem (Medulla). Neural projections from the baroreceptors synapse at the medulla, providing constant information about blood pressure. The baroreceptors are located in the aortic arch and carotid sinus . They are stretch sensitive, measure arterial pressure (close to the left ventricle!)
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2/28/10 Baroreceptor Reflex (4) Increases in MAP will cause and increase in arterial stretch, while a decrease will cause the opposite.
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2/28/10 The Respiratory The respiratory system serves as a means of providing larger animals (where diffusion is no
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This note was uploaded on 02/27/2010 for the course PHYSIOL 2210 taught by Professor Betts during the Spring '10 term at UWO.

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Phystut12 - Cardiovascular III(cont Andrew MacDonald Click...

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