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)
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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- Winter '13