Review Exam 3 - Regulation of Mean Arterial Pressure...

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Regulation of Mean Arterial Pressure Introduction o MAP = CO x TPR o Two factors influence blood flow to an organ: MAP and organ’s resistance o Any decline in MAP tends to compromise blood flow to all systemic organs o Controlled by medulla oblongata Calculating MAP o Defined as the average arterial pressure during a single cardiac cycle o MAP is usually between 70-110 mmHg If MAP falls below this, organ will not get enough blood flow and will become ischemic o MAP = HR x SV x TPR o ^ in CO or TPR = ^ in MAP MAP regulation o Negative feedback systems incorporating pressure sensors called baroreceptors that sense the arterial pressure o Depolarization triggers increased action potentials o ^ BP = ^ baroreceptors ^ parasympathetic stimulation to decrease HR v sympathetic HR v stroke volume to bring BP back down to normal o v BP = opposite of above Hypertension o Chronic condition that develops slowly over long periods of time o Baroreceptors lose their sensitivity and set “normal” to a higher pressure over time Once this occurs, baroreceptors cannot correct the problem o Can lead to significant organ damage and must be controlled by drugs and exercise Blood Pressure o Eating habits, how much water and blood are in your body, and salt intake can effect BP. Also health of your kidneys and certain hormones o Atherosclerosis (hardening of arteries) – makes arteries prone to injuries and tears Cholesterol and fat are more likely to build up in these tears heart attack or stroke o Stroke 1 st : blood vessels can break, leaking blood into the brain 2 nd : blood clot, blocking blood flow o Heart attack: coronary artery that bring blood to the heart become blocked and the heart cannot get enough oxygen o Enlarged heart: ^ BP makes heart work harder and overtime the heart fails to pump as much blood as the body needs, and fluids back up into the lungs o Waste builds due to kidney damage
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Blood Introduction o Contains 10 pints of plasma, RBC (erythrocytes), and WBC (leukocytes and platelets) o RBC’s carry oxygen and nutrients, platelets stop bleeding and help heal our wounds and prevent infection, plasma carryies an array of proteins that regulate bleeding and clotting
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Review Exam 3 - Regulation of Mean Arterial Pressure...

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