Question

The pumping action of the heart is due to the
A. Bones of the heart
B. Muscles of the heart
C. Spaces in the heart
D. Both B and C

Answer 1

Hint: Heart is a highly vascularized, hollow conical organ situated in the center of the thoracic chamber within a space called the mediastinum. The heart is enclosed within the double-layered peritoneum and pericardium. It is well known as the pumping organ of the body since it is responsible for the transport of blood throughout the body via an extensive network of veins, arteries, and capillaries.

Complete answer:
A heart is roughly about the size of one’s fist having a broad base and a narrow apex. It is situated a bit towards the left side of the thoracic cavity. The heart is mesodermal in origin measuring about 12cm in length and 9cm in breadth. It weighs around 250-300 grams. The heart is myogenic and self-regulatory or autoregulatory. The rhythm of the heart is not under the regulation of the central nervous system (CNS). However, the rate of it can be altered by the nervous system’s action by working in close association with the hormonal system of the body.
The wall of the heart is made up of three layers namely:
1. Epicardium (outer)
2. Myocardium (middle)
3. Endocardium (inner)
Internally the human heart is divided into four chambers or cavities named atria and ventricles, each two in number. These chambers serve the primary purpose of storing the oxygenated or deoxygenated blood before it is pumped out of the heart to different parts of the body. These chambers of the heart also provide enough space for muscles to contract in order to generate substantial pressure to pump blood throughout the body.
Hence, the correct answer for the given question is option is (D)-Both B and C.

Note: In the human heart the heartbeat originates from modified cardiac muscles called the sinoatrial node (SA node) which lies in the right atrium and possesses the power of generating the wave of contraction. The left chambers of the heart are filled with oxygenated blood whereas the right with deoxygenated blood.