How many chambers are there in a mammal's heart?

Correct option is C

​The correct answer is (c) 4

Explanation:

Mammals, including humans, lions, elephants, and whales, have a four-chambered heart. The heart is divided into four chambers to ensure the complete separation of oxygenated and deoxygenated blood, which is crucial for maintaining a high metabolic rate.

The four chambers are:

1. Right Atrium – Receives deoxygenated blood from the body.
2. Right Ventricle – Pumps deoxygenated blood to the lungs for oxygenation.
3. Left Atrium – Receives oxygenated blood from the lungs.
4. Left Ventricle – Pumps oxygenated blood to the entire body.

This double circulation system helps mammals maintain a constant body temperature (warm-blooded nature) and ensures efficient oxygen supply to organs.

Information Booster:

• The septum (wall of muscle) divides the left and right sides of the heart, preventing the mixing of oxygenated and deoxygenated blood.
• The heartbeats are regulated by the sinoatrial (SA) node, known as the natural pacemaker of the heart.
• The average resting heart rate of mammals varies:
• Humans: 60-100 beats per minute
• Elephants: 25-30 beats per minute
• Mice: 500-600 beats per minute

Additional Knowledge:

• Amphibians and most reptiles (except crocodiles) have a three-chambered heart with two atria and one ventricle, leading to some mixing of oxygenated and deoxygenated blood.

• Fish have a two-chambered heart consisting of one atrium and one ventricle, where blood is pumped in a single circulatory system.