A tube the width of a drinking straw
330 words over 29 numbered lines, then 7 parts worth 13 marks (Modular Unit 2 (4WBI2) style, 12–13 marks). Read the article, answer each part, then open its mark scheme and set your mark.
Illustrative article written for Scholar Lab, not a Pearson text. The biology is real; the studies, people and figures are invented or rounded for practice.
A tube the width of a drinking straw
The heart is made of muscle that never rests. Like every other tissue,
heart muscle needs a constant supply of oxygen and glucose. These are
delivered by the coronary arteries, which branch over the outside of
the heart. Each one is only about as wide as a drinking straw. The
heart beats about seventy times a minute at rest, pumping blood from
the right ventricle to the lungs and from the left ventricle to the
rest of the body.
In coronary heart disease, fatty material builds up in the walls of
the coronary arteries. The lumen becomes narrower, and less blood can
flow through. A patient may feel chest pain during exercise, when the
heart beats faster and needs more oxygen. If a blood clot forms on the
fatty material, the artery can be blocked completely. The heart muscle
beyond the blockage starts to die within minutes. This is a heart
attack.
Arteries carry blood away from the heart at high pressure. They have
thick walls containing muscle and elastic tissue, which stretch and
recoil as each surge of blood passes. Damage to the inner lining of an
artery makes it easier for fatty material to build up.
Some risk factors for coronary heart disease cannot be changed, such
as age and a family history of the disease. Others can, including
smoking, high blood pressure, a diet high in saturated fat and a lack
of exercise. Figure 1 shows illustrative data from a study that
followed a large group of middle-aged adults for ten years.
A narrowed coronary artery can be widened by a stent. A doctor passes
a thin tube into an artery in the wrist or groin and guides it to the
heart. A tiny balloon is inflated inside the narrow section, and a
mesh tube is left in place to hold the artery open. Most patients go
home the next day. They are then advised to stop smoking, to eat less
saturated fat and to exercise regularly.
Figure 1 Heart attacks in adults with different risk factors
Read the article and study the figure. Use the information in the article and your own knowledge to answer the questions. The lines in brackets show where to look; select them to highlight the text.
Use the information in the article and your own knowledge to answer the questions. The lines in brackets show you where to look; select them to highlight the text.
State what is meant by the term risk factor.
(1)Name the blood vessels that supply the heart muscle with oxygen and glucose.
(1)Describe what Figure 1 shows about the effect of having more than one risk factor.
(2)Use Figure 1 to calculate how many times more heart attacks there were in smokers with high blood pressure than in people with neither risk factor.
(2)Explain how the structure of an artery suits it to carrying blood at high pressure.
(2)Explain why heart rate increases during exercise.
(3)Suggest why patients who have had a stent fitted are still advised to stop smoking and eat less saturated fat.
(2)Total for this question: 13 marks
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