Question

Describe the internal structure of human heart with the help of diagrams.

Answer 1

The heart is a roughly cone shaped hollow muscular organ that lies in the thoracic cavity. The heart wall is composed of three layers of tissue- pericardium, myocardium and endocardium.

The heart is divided into a right and left side by the septum. The heart has four chambers, two relatively small upper chambers called atria and two larger lower chambers called ventricles. The walls of the ventricles are relatively thicker than atrial walls.

The two atria are separated from each other by a thin, muscular wall called the inter-atrial septum and the right and left ventricles are by a thick-walled, inter-ventricular septum. The inter-atrial septum and inter-ventricular septum prevent mixing of deoxygenated blood in the right side of the heart with oxygenated blood in the left side of the heart.

The atria and ventricle of the same side are seperated by a thick fibrous tissue called the atrio-ventricular septum.

The opening between the right atrium and the right ventricle is guarded by a valve called as the tricuspid valve, whereas a bicuspid valve guards the opening between the left atrium and the left ventricle.

The largest artery is the aorta which arises from the left ventricle supplies blood to all the body parts except lungs.

Pulmonary artery that arises from the right ventricle carries deoxygenated blood to lungs.

The openings of the right and left ventricles into the pulmonary artery and the aorta respectively are provided with the semilunar valves.

The valves allow the blood to flow only in one direction, i.e. from the atria to the ventricles and from the ventricles to the pulmonary artery or aorta.