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2012 Biology AS level EMPA




Contents

The Heart & Heart Disease

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Structure
The Cardiac Cycle
Diastole
Atrial Systole
Ventricular Systole
Cardiac Cycle Graph
Controlling the Cardiac Cycle
Cardiac Output
Heart Disease
Atheroma
Thrombosis
Aneurysm
Risk Factors Associated With CHD
Drugs & Disease
Drug Testing
Tests
Ethical Issues
Vaccination
Vaccination Programme
Problems With Vaccination


Refer to the EMPA Revision Booklet for all…

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Structure
The heart consists of a double pump mechanism that is
powerful enough to pump oxygenated blood all around out
body. It is made from cardiac muscle that creates enough
pressure to do this. It transports oxygen, glucose and carbon
dioxide amongst other things, oxygen & glucose are needed for…

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thickest walls so it can create a very high pressure due to the
fact it has to send blood all across the whole body.




The Cardiac Cycle

One complete sequence of contraction and relaxation is
known as the cardiac cycle. Blood flows from a region of high
pressure to a…

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Blood Flow Atria >
Ventricl
es

Atrioventricular Ope
Valves n
Semi Lunar Clos
Valves ed
Ventricular Systole
The ventricles now contract, increasing the pressure and blood
is pushed through the semi lunar valves, as pressure in the
ventricles is higher than that of the aorta and pulmonary
artery. The atrioventricular…

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Cardiac Cycle Graph

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Ventricular
Valve Diastole Atrial Systole
Systole
Atrioventricula Open Open Closed
r
Semi Lunar Closed Closed Open




Controlling the Cardiac Cycle

The heart is myogenic, meaning, contractions arise from
within the cardiac muscle itself. Two nodes, the sinoatrial
node and the atrioventricular node, control it as follows.

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The SAN acts as a pacemaker and provides and electrical impulse that
initiates a heart beat.

The AVN allows the ventricles to fill with blood before they contract.

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Cardiac Output

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Cardiac output is a measure of the total amount of blood that
is pumped out from the heart in one minute; to calculate it
you use this equation:

Cardiac Output = Stroke Volume x Heart Rate

Stroke volume is the volume of blood pumped put from each
ventricle during each…

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