Heart Structure

The heart is principally composed of cardiac muscle and connective tissue. Cardiac muscle is a hard involuntary muscle wich is responsible for the blood pump and it is suplyed with blood by the coronary arteries

The heart is a muscular organ located in the centre of the chest. It pumps blood containing oxygen from the lungs to the body and passes blood back to the lungs to absorbe more oxygen

The Heart

Arteries have a thick layer of muscle and elastic fibers with a small lumen wich helps to carry blood fast. The size of the lumen variates in vasoconstriction and vasolidation.Veins have a thin layer of muscles and elastic fibers and a large lumen wich does not allow a fast flow of blood.Capilaries have single celled walls that allows them to reach every part of the body.......................................................................................................................................................................................................................................................................................................................................................................

Describe the handout on this blackboard...

The heart is

Blood enters from the vena cava/P.vein and goes to the artrium.Atrium contracts pushing blood through the Tricuspid/Bicuspid valve to the ventricle.Then, the ventricle contracts pushing blood through the Pulmonary/Aortic valve to the lungs/body and head.

Both the Sinoatrial and Atrioventricular node stimulate the Myocardium (cardiac muscle) wich is responsible for systoles and dyastoles.

All four chambers in the heart work properly because of ELECTRICAL IMPULSES

Nerves supplying the heart change the rate in wich impulses are sent to meet the needs of the body.

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