Features of the structure of the systems of internal organs of the body of fish and their functional significance.

Features of the structure of the systems of internal organs of the body of fish:

the operculum covers the branchial chamber;
the lateral line is a set of sensory receptors that respond to mechanical vibrations of water;
the dorsal fin plays the role of a keel (maintaining balance);
the cerebral hemispheres are poorly developed in comparison with the optical lobes;
the swim or gas bladder is the dorsal diverticulum of the esophagus. Its volume can be varied and is used to adjust the hydrostatic level of the fish;
a pneumatic canal connects the swim bladder and the dorsal esophagus;
the length of the intestine is a function of the diet: in phytophages it is longer;
the kidneys have a very variable structure;
both gonads (ovaries or testes) are elongated organs that communicate with the genital pores through the gonad.