Question

Four chambered heart occurs in
a. Amphibia
b. Chelonia
c. Birds and Crocodile
d. Ophidia

Answer 1

Hint: The heart is the central organ of the circulatory system of man and animals. It forces the blood into the arteries and maintains the circulation of blood throughout the body. The heart that is present in the vertebrate is a well-developed organ. There is a muscular sac present with valves and a thick layer of muscle which is called myocardium.

Complete answer:
> Option C: The four chambered heart is divided into four chambers consisting of two atria and two ventricles. The crocodilian heart holds one of the complex circulatory systems. It has a four-chambered heart and two ventricles and both left and right aorta are also present. Like the crocodile, birds also bear a four-chambered heart. The mechanism involving the two chambers ensures the difference in the circulation to the lungs and blood that is pumped to different parts of the body, and both crocodilians and birds have heart valves.

> Option A: The heart found in the amphibians generally has a structure of tripartite. The amphibians' heart is divided into two atria but a single ventricle. The lungless salamanders do not possess any atrial septum. Another group, the caecilians, show signs of a septum in the ventricle. The amphibians may or may not have septa in both atrium and ventricle. So, the heart of amphibians is three-chambered.

> Option B: Chelonia belongs to the class of reptiles. They breathe with their mouth closed. Like the other animals, the heart of Chelonia consists of four chambers i.e. two atria and two ventricles and they are arranged in a linear sequence.

> Option D: The species belong to the class Ophidia which possesses a heart with three chambers; right and left atria and one ventricle. In this class, the walls of the heart chambers are lined with the endocardium.

Hence, the correct answer is option (C).

Note: The heart is the main organ of the circulatory system which can be found in almost each and every animal. The heart present in vertebrates is comparatively developed than the hearts of invertebrates. Different species belong to a different class, have a different structure. Like amphibia and Ophidia hold a heart that has three chambers, while the heart found in the birds and crocodile, and reptile possesses a four-chambered heart.