Heart and its structure

8/11/2019 Heart and its structure

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HEARTAND

ITS STRUCTURE

SUBMITTED BY SUBMITTED TODIVYA SIVADASAN DIVYA.S

NATURAL SCIENCE (LECTURER)13375010


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In human being heart is situated in thoracic cavityunder the breast bone and between the lungs.

A persons heart generally as large as his/her fist .

It is 12cm long and 9cm wide and weigh 300gm.

It is surrounded by a double layered membranecalled pericardium. In between these layer is afluid called pericardial fluid.


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BLOOD VESSELS ARISING FROM

HEART

Blood vessels that carry blood to theheart are Veins

Blood vessels that bring blood to heartfrom different parts of the body are Arteries

Pulmonary vein, Superior Vena Cava,Inferior Vena Cava, Pulmonary artery


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CHAMBERS IN THE HEART

Heart has four chambers.The upper two chambers are right

atrium and left atrium .The lower chambers are right ventricle

and left ventricle.

The atria and ventricles are separatedby muscular wall.


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VALVES PRESENT IN THE HEART

Valve in between right atrium and rightventricle is Tricuspid valve.

Valve in between left atrium and rightventricle is Bicuspid valve.The opening of the aorta from the left

ventricle are guarded by valves calledSemilunar valves.


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The right half of the heart contains onlydeoxygenated blood or impure blood .The left half of the heart containsoxygenated blood or pure blood .

The wall of the ventricles are thickerthan atria.Left ventricles are thick because it

supplies oxygenated blood to wholebody.


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WORKING OF THE HEART

From different parts of the body blood reaches toright atrium through superior and inferior venacava.

From lungs oxygenated blood reaches to left atrium through Pulmonary vein .When blood reaches the atrium, it contractsblood enters the ventricle.When ventricle contracts, deoxygenated blood inthe right ventricle enters the lungs through

pulmonary artery


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When ventricle contracts, deoxygenated bloodin the right ventricle enters the lungs through

pulmonary artery. Blood gets oxygenated in the lungs.

Oxygenated blood in left ventricle reachesdifferent parts of the body through Aorta. This blood release oxygen and receive carbon

dioxide . Then it reaches right atrium through vena

cava and the process continues.


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HEART BEAT

Contraction of heart is known as Systole . Relaxation of heart is known as diastole . A Systole and Diastole constitute Heart

Beat . The normal beat rate is 72 per minute . The time taken for one contraction and

relaxation of the heart is 0.8 seconds .


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BLOOD PRESSURE

As the heart contracts and pushes the blood, thepressure causes the arteries to distend toaccommodate the incoming blood. This pressure is

called Systolic pressure (120mm/hg). When the ventricle relaxes, the pumping of blood

into the arteries stops. This pressure is calledDiastolic pressure (80mm/hg).

It can be measured by an instrument calledSphygmanometer.


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Heart and its structure

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