HUMAN HEART
Location :- Centrally located but tilted towards left.
Weight :
In males = 270-310 gm
In females = 240-280 gm
Size : sized of a closed fist.
Shape : Cone shape.
Wall of heart :-
Has 3 layers -
1. Epicardium (outer layer)
2. Myocardium (middle layer)
3. Endocardium (inner layer)
STRUCTURE OF HUMAN HEART
• Human heart is four chambered and arteriovenous in nature.
• Divided into upper atria/auricles and lower ventricles by atrio-ventricular septum.
Atria :
• Divided into right and left atria by inter-atrial septum which prevents mixing of oxygenated and deoxygenated blood.
• Right atria opens into right ventricle through AV appreature guarded by Tricuspid valve.
• Right atria receive blood from - (i) superior vena ceva(from upper part of the body) (ii) Inferior vena cava (from lower part of the body.
• Right atria received deoxygenated blood only.
• Left atria opens into left ventricle through AV appreature guarded by bicuspid valve(mitral valve).
• Receive oxygenated blood from lungs by two pair of pulmonary vein.
Note :- Both auricles/atria are thin walled because they have to push the blood only upto ventricles.
Ventricles :
• Divided into right and left ventricle by inter-ventricular septum.
• Right ventricle pump deoxygenated blood to lungs by pulmonary artery.
• Left ventricle pump oxygenated blood to body part through arota.
• Opening of pulmonary artery and arota is guarded by semilunar valve.
Note :- Both the ventricles thick walled. Left ventricle is much thicker than right ventricle (about three times) because left ventricle has to push the blood to all the body parts while right ventricle has to push the blood to closely lying lungs only.
