Question

Heart is two-chambered in
a. Fishes
b. Amphibians
c. Reptiles
d. Birds
e. Mammals

Answer 1

Hint: The heart is a muscular organ present on the left side of the human body. It consists of ventricles and auricles. It pumps blood from the heart to other tissues. It carries oxygen and nutrients to the body. It is the major constituent in the human circulatory system. It helps in thermoregulation.

Complete answer:
> Fishes have a two-chambered heart. It comprises one auricle for blood and one ventricle. So that means fishes have a two-chambered heart. Thus, the correct option is Fishes.

> Amphibians have a three-chambered heart. It comprises two auricles and one ventricle. So, option B- Amphibians is incorrect.

> Reptiles have an incompletely four-chambered heart. It comprises two auricles and partly divided ventricles. So, option C is incorrect

> Birds have a four-chambered heart. It comprises two auricles and two ventricles. So, option D- Birds is incorrect.

- Mammals have a four-chambered heart. It is composed of two auricles and two ventricles.
- The foundational heart of fishes comprises four chambers in the arrangement, the sinus venosus, chamber, ventricle, and conus or bulbous. Valves between the chambers and compression of all chambers aside from the bulbous keep up a unidirectional blood move through the hearts
- The heart is made out of commonplace vertebrate cardiovascular muscle, even though there might be minor contrasts in the conveyance of suddenly dynamic cells, the rate and nature of the spread of excitatory waves, and the qualities of resting and activity possibilities between various fish and different vertebrates.

Hence, the correct answer is option (A).

Note: Fish hearts need thoughtful innervation. The degree of vagal tone fluctuates impressively and is influenced by numerous components. In some fish, the heart is aneural (without vagal tone) during exercise and may look like a segregated mammalian ventricle with expanded venous return causing expanded cardiovascular yield. Numerous components could increment venous return in practicing fish.