Biology AS AQA Unit 1 The Heart and Heart Disease

Made these notes for my year 12 summer exam to revise and read over. There are spelling mistakes in most of my files but due to the busy exam schedule I had no time to correct them (sorry).

Most files have more information than what is needed but I feel it helps you feel more confident walking into the exam if you have a greater knowledge background and may help when having to apply knowledge to questions. Good luck :)

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  • Created by: Chelcie
  • Created on: 02-09-13 12:39

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Page 1

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The Heart and Heart Disease
Mammals need a double circulatory system for the heart to increase the blood pressure before it is
distributed to the rest of the body.

ATRIUM
It is a thin walled and elastic and stretches as it collects blood.
Pumps blood to the ventricles and therefore…

Page 2

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DIASTOLE (Relaxation)
Blood returns to the atria of the heart through the pulmonary vein and the vena cava.
The atria fill; pressure rises pushing open the atrioventricular valves and allowing blood to
pass through to the ventricles.
The muscular walls of atria and ventricles are both relaxed.
This causes the…

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HOW IS THE CARDIAC CYCLE CONTROLLED?

Muscle is MYOGENIC (contraction is initiated within the muscle itself) rather than neurogenic
(nervous impulse from the outside causing the contraction)

1. A wave of electrical activity is INITIATED from the sinoatrial node (SAN) (the pacemaker)
across both Atria causing them to contract.
2.…

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CHD
CHD affects the coronary arteries which supply the heart muscle with glucose and oxygen that is
required for respiration.

ATHEROMA
Atheroma is a fatty deposit that forms WITHIN THE WALL of an artery.
It begins as fatty streaks of accumulated white blood cells that have taken up low-density
lipoproteins…

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Aneurysms frequently burst forming a haemorrhage and therefore loss of blood to the region
served by that artery.
A brain aneurysm is known as a cerebrovascular accident (CVA) or a stroke.

MYOCARDIAL INFARCTION
Heart attack
Blockage in the coronary artery causing the heart to stop beating as the blood supply…

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