Cardiovascular System
Heart is the center of cardiovascular system by the end of the long life a person heart may have beat more than 3.5 billion time.
Each day average heart beats about 1 lakh times and pumping about 7, 571 liters blood in days.
Size of the Heart
Heart is cone shaped, hollow muscular organ.
12 cm long, about 9 cm wide at its broadest end and 6 cm thick.
Weight of Heart
Adult male; 250-300gm
Adult female; 200- 275gm
Location of the Heart
Heart is located in thoracic cavity in middle mediastinum and located between lungs and in middle of the chest and behind slightly to left of the sternum.
It rest on the diaphragm near middle of thoracic cavity about 2/3rd mass of the heart lies in left of the body.
It is pointed as the apex and broadest at the base.
Organ Associated with Heart
Inferiorly; Apex, rest on diaphragm
Superiorly; Aorta, superior venacava, pulmonary artery and pulmonary vein
Posteriorly; Esophagus,trachea, left and right bronchus, thoracic vertebrae
Anteriorly; Sternum, ribs and intercostal muscle
Laterally; the lungs, left lung overlaps the left side of the heart
Structure of Heart
Covering of Heart
Heart enclosed in double walled sac (fibrous and serous) called pericardium.
Pericardium have triple layered.
Pericardium surrounds and protect heart.
Pericardium consist of -
1. Fibrous pericardium
2. Serous pericardium
a. Outer parietal layer
b. Inner visceral layer
Function of Pericardium
1. It prevent over stretching of heart
2. It provide protection of heart
3. It encloses the heart and protect heart against sudden overfilling
4. It anchors heart in mediastinum
5. It reduces friction between membrane as the heart movement
6. Allow the Heart to move in limited way and rapid contraction
Walls of Heart/ Layers of Heart
Wall of Heart made upto 3 layers -
1. Outer epicardium (pericardium)
2. Mycardium
3. Endocardium
1.Outer Epicardium (Visceral pericardium)
External layer; Visceral layer of serous pericardium
Smooth, slippery texture to the in out most surface of Heart
Inside epicardium are main coronary blood vessel that supply blood to and drain from heart.
2. Myocardium; Middle layer
Cardiac muscle
Thickest layer of heart which consist of cardiac muscle and coronary artery.
It is responsible for the contraction and relaxation of heart.
3. Endocardium
Innermost endocardium continuous with is thin layer of endothelium.
Provide smooth lining for inside of the heart and cover the valves and muscle of heart.
Permit smooth flow of blood inside heart.
Chambers of the Heart
Heart contains four chamber-
Atrium
1. Right atria
2. Left atria
Ventricles
3. Right ventricles
4. Left ventricles
Heart divided into right and left side by septum.
Atria; Recieving chamber
Ventricle; Discharging chamber
Thickness of Wall
The atria are thin walled and ventricle are comparatively thick to atrium.
Left ventricle is largest and strongest chamber of the Heart.
The left ventricle chamber wall have to push blood through aortic valve into the systemic circulation of body.
Atria
(Opening present in right atrium)
1. Right atrium
Right upper chamber of Heart receives deoxygenated blood from superior and inferior venacava and coronary sinus, anterior cardiac veins and small cardiac vein, send down to right Ventricle (through tricuspid opening).
2. Left atrium
Left upper chamber of heart, receives oxygenated blood from left and right pulmonary vein (4), pump it to the left ventricle (through mitral valve or bicuspid valve).
Ventricles
3. Right ventricles
Receives deoxtgenated blood from right atrium and pump it to the lungs through pulmonary artery.
4. Left ventricle
It receives oxygenated blood from left atrium and pump it into aorta.
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