Question

What is the structure and function of the heart of a fish?

Answer 1

Fish consists of a simple closed circulatory system that comprises two heart chambers named as atrium and ventrium. The characteristics of both the chambers include thick and muscular walls.

Complete answer:
Fish consists of a closed circulatory system in which blood contained inside blood vessels flows throughout the body. The blood flows in one continuous loop that is from the tissues to the heart to the gills and then back to the tissues. The two chambers present in the fish heart are termed as the atrium and the ventricle, both composed of thick and muscular walls. Blood flowing in the veins from the body tissues to the heart initially enters a sac-like compartment termed as the sinus venosus from where it flows to the atrium. From atrium the collected blood gets passed into the ventricle, where it gets pumped into bulbus arteriosus which can be defined as a tube shaped region of the heart that connects the heart to the aorta. The aorta can be described as a large artery that brings the blood from the heart to the gills, where it becomes oxygenated and travels through blood vessels to the tissues of the organism.

Note:
The fish consists of single closed loop circulation. The circulatory system of fishes are termed as single cycle circulation as the system consists of only one circuit that is the blood gets pumped through the capillaries of the gills and on to the capillaries of the body tissues.Thus,the heart of fish have only a single pump that consists of two chambers that are atrium and ventrium.