CBSE Class 10 Answered
Heart is a hollow, conical organ. It is a reddish brown, muscular organ, made up of cardiac muscles and enclosed in a double walled membranous sac called pericardium. Human heart is 4 chambered. The 2 upper, smaller chambers are the atria or auricles, whereas the lower, larger chambers are the ventricles. Atria are thin walled whereas the ventricles are thick walled. Auricles receive blood and are the receiving chambers and ventricles transport blood, hence they are the conducting chambers.Several blood vessels bring and carry blood to and from the heart.
The right auricle receives deoxygenated blood from the anterior and posterior parts of the body. This blood then flows into right ventricle, from where it is taken to the lungs for oxygenation. The oxygenated blood is then taken to the left auricle, from where it passes to the left ventricle. The left ventricle contracts and pumps the blood to all the parts of the body.