Question

How many chambers are there in the human heart?

Answer 1

The human heart is the major circulatory ‘pump’ of the circulatory system. It circulates the blood throughout the body, helps to supply nutrients and oxygen to the body and at the same time removes the metabolic wastes and carbon dioxide from the tissues.
In humans, there are two distinct circulatory pathways present, one for the lungs and another one for the rest of the body.

Complete answer:
The human heart has four distinct chambers- two auricles and two ventricles. The heart is actually divided into the left and right side by sheath of muscular tissue called auriculo-ventricular septum.
The left side is divided into the upper left auricle and lower left ventricle.
Likewise, the right side is divided into the upper right auricle and lower right ventricle.
The auricles are the receiving chambers and the ventricles are the pumping chambers.
The left auricle receives deoxygenated blood from all the tissues of the body. The blood then passes through the bicuspid or mitral valve into the left ventricle from where the blood goes into the pulmonary circulation, i.e., lungs for purification.
Then back from the lungs, the oxygenated blood is received into the right auricle. The blood then passes through the tricuspid valve into the right ventricle and finally the right ventricle pushes the blood into the aorta which then circulates the blood throughout the body.

Note:
The human heart is a result of evolution. In the initial days, when life forms were aquatic, the heart consisted of only two chambers, like in fishes. There was no mechanism to prevent mixing of oxygenated and deoxygenated blood.
As the life forms started to inhabit the terrestrial environments, an efficient circulation was required, so the heart evolved to form the present day 4 chambered structure.