The heart lies in the thoracic cavity in the media - sternum (the space between the lungs ).It lies oblique, a little more to the left then the right and present a base above and apex below .The apex is about 9cm to the left of the midline at the level of the 5th intercostal space, the base extend to the level of the 2nd ribs .
* Structure of heart *
The heart is composed of three layer of tissue -----------
1. Pericardium
2. Myocardium
3. Endocardium
The pericardium is the outer layer and is made of to sac . The outer sac ( the fibrous pericardium ) consist of fibrous tissue. The inner layer of pericardium is cold serous pericardium . The outer layer of parietal pericardium. Tha inner layer of serious pericardium is cold visceral pericardium . The serous membrane consist of ephythelium cells .It secretion serous fluid in to the space bitween the visceral peirital layer which allow smooth movement bitween the heart beats .
The mayocardium composed of specialised cardiac muscle found only in the heart . It is not under voluntary control .
This form the chamber and valve of the heart . It is a thin smooth membrane to insure smooth flow if the blood through the heart .It is the inner most layer of heart
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Tricuspid valve -- the valve present between the right atrium and right ventricle . which allow the blood to flow from right atrium to right ventricle . the tricuspid valve has three flap .
Bicuspid valve -- it is also called mitral valve .It is situated between the left atrium and left ventricle .It has a two flaps .
Pulmonary valve -- this valve present between the right ventricle and pulmonary artery .
Aortic valve -- this valve present between the left ventricle and aorta .
1. Arterial supply-- the heart is supply with arterial blood by the right and left coronary artery .Which branch from aorta emediatly distol to the aortic valve . the coronary arteries recive about 5℅ of the blood pump from the heart .
3.Venous drainage -- most of the venous blood is connected in to a number of cardiac vein that join to the from the coronary sinus ,which open in to the right atrium .
Very nice sir
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