Anatomy and Physiology Answer Key

3 heart patients need careful supervision because the

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Unformatted text preview: eads to blockage and obstruction of blood flow in the affected artery. The region of heart muscle normally supplied by the affected artery dies, causing severe pain and irregularity in the heart beat. Damage to the heart muscle may be so severe, it may lead to heart failure. 2. (a) Controllable risk factors for CVD are those that can be altered by changing diet or other lifestyle factors, or by controlling a physiological disease state (e.g. high blood pressure, or high blood cholesterol). Uncontrollable risk factors are those over which no control is possible i.e. genetic predisposition, sex, or age. Note that the impact of uncontrollable factors can be reduced by Exercise and Blood Flow (page 124) 1. (a) Atheroma increases the risk of aneurysm because it weakens the arterial walls and, combined with high blood pressure leads to increased risk of the arterial wall ballooning out (aneurysm) and rupturing. (b) Plaque material from an atheroma can detach from the artery wall and enter the circulation where it can bock small vessels and lead to blood clot formation (thrombosis) and consequently, stroke. 3. (a) LDL deposits cholesterol on the endothelial lining of blood vessels, whereas HDL transports cholesterol to the liver where it is processed. A high LDL:HDL ratio is more likely to result in CVD because more cholesterol will be deposited on blood vessels and contribute to atherosclerosis. (b) The LDL:HDL ratio is a more accurate predictor of heart disease risk than total cholesterol per se. Answers for missing values are listed from top to bottom under the appropriate heading: At rest Exercise (% of total)(% of total) Heart 4.0 4.2 Lung 2.0 1.1 Kidneys 22.0 3.4 Liver 27.0 3.4 Muscle 15.0 70.2 Bone 5.0 1.4 Skin 6.0 10.7 Thyroid 1.0 0.3 Adrenals 0.5 0.1 Other 3.5 1.0 2. The heart beats faster and harder to increase the volume of blood pumped per beat and the number of beats per minute (increased blood flow). 3. (a) Blood flow increases approximately 3.5 times. (b) Working tissues require more oxygen and nutrients than can be delivered by a resting rate Biozone International 2009 Photocopying Prohibit...
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This document was uploaded on 01/28/2014.

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