External features of human heart
- Human heart is a muscular, hollow organ situated slightly towards left side of the thorasic cavity.
- It is made up of special muscles called cardiac muscles.
- It is conical in shape with apex facing downwards and the broad base directed upwards.
- It is the size of the fist of the person.
- It is protected on all sides by rib cage and by vertebral column on the backside.
- Heart is enclosed in a double layered transparent membrane called pericardium.
- Pericardium is filled with a fluid called pericardial fluid, Which protects the heart from physical shocks, blows and frictions.
- External grooves indicate the internal division of the heart into four chambers. The anterior (upper) two chambers are auricles and the posterior (lower) two chambers are ventricles. These auricles and ventricles are separated by horizontal and vertical grooves (lines) and formed as four chambers.
- Venacavae bring deoxygenated blood to the heart. Aortae carry oxygenated blood from the heart.