GENERAL HISTOLOGY

Detailed explanation-1: -Many people refer to octopus limbs as tentacles, but technically, octopuses don’t have any tentacles at all! Instead, they have arms.

Detailed explanation-2: -An octopus has eight appendages, each of which has rows of suckers running its length. But these are not tentacles-in strict anatomical terms, they are arms. A tentacle has suckers only on its pad-shaped ending. Squid and cuttlefish have arms, but also tentacles.

Detailed explanation-3: -The seven-arm octopus (Haliphron atlanticus) is one of the two largest known species of octopus; based on scientific records, it has a maximum estimated total length of 3.5 m (11 ft) and mass of 75 kg (165 lb). The only other similarly large extant species is the giant Pacific octopus, Enteroctopus dofleini.

Detailed explanation-4: -The giant Pacific octopus has three hearts, nine brains and blue blood, making reality stranger than fiction. A central brain controls the nervous system. In addition, there is a small brain in each of their eight arms-a cluster of nerve cells that biologists say controls movement.