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HEART AND HEART DISEASE
Heart is a muscular organ that lies in the thoracic cavity behind the sternum
(breast bone).

STRUCTURE
There are four cavities called chambers. The two upper chambers are called
the right and left atria. The two lower chambers are the right and left
ventricles. The pump…

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the papillary muscles in the ventricle walls. They PREVENT BACKFLOW of
blood into the atria when ventricles contract. There are two kinds of valves:

THE ATRIOVENTRICULAR (bicuspid) VALVES- They are located
between atria and ventricle. The valve on the left is called BICUSPID and
right is called TRICUSPID VALVE.
SEMILUNAR…

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THE CARDIAC CYCLE
The heart undergoes a sequence of events that is repeated 70 times each minute.
This is known as cardiac cycle

There are two phases to the beating of the heart: contraction (systole)
and relaxation (diastole).
Contraction occurs separately in the ventricles and
the atria.



RELAXATION OF THE…

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CONTRACTION OF ATRIA (ATRIAL SYSTOLE)




CONTRACTION OF THE VENTRICLE
(VENTRICULAR SYSTOLE)

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Blood
always move from a region of high pressure to low pressure




VALVES IN CONTROL OF BLOOD FLOW
ATRIOVENTRICULAR VALVES- these prevent back flow of the blood
when contraction of the ventricle means that VENTRICULAR PRESSURE
EXCEEDS ATRIAL PRESSURE. Closure of these valves ensure, when ventricles

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contract blood within them moves to the aorta and pulmonary artery rather than
back to the atria

SEMI LUNAR VALVES- these prevent backflow of the blood into
ventricles when recoil action of the elastic walls of aorta and pulmonary artery
creates a greater pressure in the vessels than ventricles

POCKET…

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Initial stimulus for contraction originates from here. It has a basic rhythm of
stimulation that determines the beat of the heart. The sequence of the cardiac
cycle that controls the cardiac cycle is as follows:




PRESSURE AND VOLUME CHANGES OF THE
HEART

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HEART DISEASE
CORONARY HEART DISEASES affects the pair of blood vessels, the coronary
arteries, which supply the heart muscle with glucose and oxygen for respiration.

ATHEROMA
They're fatty deposits that form within the wall of an artery.

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THROMBOSIS
If an atheroma breaks through the lining (endothelium) of the blood vessel, it
forms a surface that interrupts the smooth flow of blood. This may result in the
formation of a blood clot or thrombus, this condition is an
THROMBOSIS.
This thrombus may block the blood vessel, reducing or…

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because its blood supply will be completely cut off. The symptoms include: milder,
because a smaller area of muscle will suffer oxygen deprivation.

RISK FACTORS ASSOCIATED WITH CORONARY HEART
DISEASE
SMOKING- carbon monoxide and nicotine reduces oxygen carrying capacity of
the blood
HIGH BLOOD PRESSURE
BLOOD CHOLESTEROL-
DIET- high levels…

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