HUMAN HEART (MAMMALIAN HEART) -

Position - Situated in thoracic cavity in pericardial cavity close to its front wall. Its broad base faces upward and backward. Its narrow apex faces downward, forward & slightly to the left side and rests on diaphragm.

Shape - Some conical.

Colour - Dark red.

Chamber - 4 (2 auricles & 2 ventricles)

Size - Roughy 12 x 9 cms.

Weight - Average wt. is about 300 gm. in male, 250 gm in female.

Covering - Covered by 2 pericardium. Inner serous pericardium consists of outer parital layer and inner visceral layer.

Outer fibrous pericardium is made up of white fibres.Between these two pericardial fluid (secreted by serous pericardium) present keeps the heart moist, allows it free movement, reduces friction & protect from external shocks.

Protective Cage - Sternum and ribs form protective cage.

Wall of Heart - In it three layers present. Epicardium, myocardium and endocardium. Epicardium is outer layer made up of squamous epithelium. (Mesothelium). Myocardium is made up of cardiac muscles. Endocardium consists of endothelial layer resting as a thin layer of loose connective tissue.