Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

The heart and heart disease
The heart as a pump
4 chambers to the heart, lower chambers are ventricles and the top chambers are atria
...
The atrium muscles contract
decreasing the volume of the atrium and increasing the pressure which forces the blood through the
atrioventricular valve into the right ventricle
...

Then, ventricular muscles contract, decreasing the volume and increasing the pressure, forcing the
atrioventricular valves to close and forces blood out into the pulmonary artery through the semilunar valve
...
The blood then flows into the left
ventricle and is forced out of the aorta to the rest of the body
...

The cardiac cycle
Atrial systole – atria contract, blood is forced through AV valve into ventricles
Ventricular systole – ventricles contract, blood is forced into the arteries from the bottom up
Diastole – all muscles relax
Left and right side contract at the same time
...

Coordinating the heartbeat
The heart is myogenic meaning it can work on its own without messages from the brain
...
A wave of
electrical activity is produced, the rate at which these wave are produced determines the rate of the
heartbeat – they start off atrial systole
...
The waves of electrical
activity spread over the walls of both atria and this makes the atrial walls contract
...
The
atrioventricular node conducts electricity at a slight delay, the bundle of his sends an electrical
impulse down the walls of the ventricles to the bottom; they stimulate the contraction of ventricular
walls from the base up – ventricular systole
...
Nerves in the brain
help to regulate the heartrate
...
Two separate nerves, one to speed it up and one to slow it down
...
Battery-operated pacemaker inserted under skin below collarbone and two thin wires
are passed along the major vein into the right ventricle of the heart
...

\Atheroma
Fatty deposits build up in arterial walls when the endothelium becomes damaged and inflamed
...
White
blood cells squeeze between the endothelium cells in the muscular wall which absorb fatty materials
from the blood
...
When the plaques cell die it becomes rougher, if the endothelium breaks blood

platelets will stick to the damaged site and form a clot – thrombosis
...
Part of the clot could break away and get stuck in smaller arteriole
walls where they cut of blood supply to muscle which may damage the heart
...

Myocardial infarction
It’s possible to survive with atheroma for many years without being incapacitated or aware of its
existence
...
This is due to atheroma
preventing heart muscle from getting increased blood supply during exercise
...
Most myocardial infarctions occur when a blood clot
blocks a coronary artery at the site of atheroma
...
When both
sides of the heart do not contract at the same time it causes fibrillation which means the left
ventricle will no longer produce enough force to pump blood out of the aorta
...

Genetic factors CHD tends to run in families, especially when heart attacks occur in middle age or
earlier
...

High blood pressure linked to genetic, high salt content, lack of exercise and alcohol
...
This can damage inner
surface and cause an atheroma
...

High concentration of low-density lipoproteins in the blood



---