descibe the internal structure oh human heart?
Answers
The two auricles or atria are thin-walled and are separated from each other by a thin inter-atrial septum. The right atrium receives venous (deoxygenated blood having very little 02) from the entire body through a superior and inferior vena cava. The left smaller atrium receives oxygenated blood from the lungs through four pulmonary veins.
The two auricles (atria) are separated from the ventricles by two apertures guarded by membranous valves. The valve separating right atrium from right ventricle is called right atrio-ventricular valve or tricuspid valve made up of three flaps. The valve separating left atrium from left ventricle is called left atrio-ventricular valve or mitral valve, formed of two flaps. These valves are attached with fine cords with the papillary muscles of the ventricular wall. These valves only allow blood flow from auricles into ventricles and not in opposite direction.
Both the ventricles are separated from each other by a thick inter-ventricular septum. The wall of left ventricle is much thicker than that of right ventricle. The left ventricle pushes blood into aorta which supplies blood to entire body. The opening of aorta is also guarded by a valve formed of 3 semilunar flaps. The right ventricle pumps venous blood into lungs by a pulmonary aorta. Its opening is also guarded by a valve, having 3 semilunar flaps. These valves allow the flow of blood from ventricles into the aorta and not back. Heart is formed of cardiac muscle fibres, which rhythmically contract the heart without feeling fatigue.
→ Heart is a hollow, muscular organ present in between two lungs in tye thoraric cavity. It's size is about one's fist. It is 12 cm long and 6 cm wide.
→ It's weight in male is 300 gm and 250 gm in female. It's is reddish brown in colour.
→ It's upper broad part is known as base and lower part is known as Apex.
→ It's is protected by a double members called pericardium, comprising inner visceral pericardium and outer parietal pericardium.
→ Between these layers there is a fluid called pericardium fluid. This fluid provides moisture to the heart and reduce the friction between heart wall and surrounding tissue.
→ A human heart is four chambered. Two upper; smaller chambers called atria and the lower; longer chambers called ventricle.
→ The atrium and ventricle of the same side are separated by atrio-ventricular septum.
→ Atrial septum separates the left and right atria. Inter ventricular septum separates the left and right ventricles.
→ The opening between right atrium and ventricle is guarded by a valve called Tricuspid valve.
→ And the opening between left atrium and ventricle is guarded by a Bicuspid valve.
→ Valves prevent the backward flow of blood and allow the blood to flow in one direction only.
