| There are four types of valves through
which the blood flows on its journey through the heart. The
opening and closing of the heart valves produces sounds which are termed
as the heart beats. The opening produces the first heart sound called
'Lubb' and the closure is called 'Dubb'. The valves open and close in
sequence to allow the blood to pass in of the heart are the Tricuspid
and Pulmonary valves.
On the left side are the Mitral and Aortic valves. The
sounds that you hear when you listen to a heart beat are the sharp
opening and closing of these valves.
The Circulatory System
The circulatory system provides the means of delivering
oxygen and nutrient rich blood to each cell and transporting waste products
to be removed from the body. The heart is the main pump and the engine
of the circulatory system. The system includes:
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The Heart
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The Lungs
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The Arteries
and Arterioles
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The Capillaries
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The Veins
and Venules
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The Electrical System
Unlike other muscles in your body, the heart has its
own way of controlling itself. It does not rely on signals from the brain
in order to beat. It has its own electrical system (also called the conduction
system) which controls the rate and rhythm of your heartbeat.
Sodium and potassium play an extremely important role
in the conduction system of your heart. The electrical impulses in the
heart are created when the charged ions of sodium and potassium pass through
the walls of the cells in the heart. This movement creates a change in
the charge of the cells which results in an electrical impulse. Specialized
cells in the heart have the important job of transmitting this impulse
throughout the heart in an organized manner. These specialized cells create
an invisible electrical pathway in the heart. As the impulse
moves along this pathway the muscle responds by contracting and pumping
the blood.
There can be problems that arise with the heart's electrical
system. These problems change either the place from which the impulse
originates and/or the pathway through which the impulse travels. This
results in conduction disturbances called Arrhythmias.
The electrical conduction of the heart is observed with
an electrocardiogram (ECG/EKG).
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