GENERAL HISTOLOGY

Detailed explanation-1: -The chordates are named for the notochord, which is a flexible, rod-shaped mesodermal structure that is found in the embryonic stage of all chordates and in the adult stage of some chordate species.

Detailed explanation-2: -A notochord is present in the phylum Chordata (comprising three subphyla: amphioxus, tunicates, and vertebrates) and, more arguably, in some other animals.

Detailed explanation-3: -Animals in the phylum Chordata share four key features: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail.

Detailed explanation-4: -Location: The notochord is exclusively found in the tail.

Detailed explanation-5: -In higher vertebrates, however, the notochord becomes ossified in regions of forming vertebrae and contributes to the centre of the intervertebral discs in a structure called the nucleus pulposis (Linsenmayer et al., 1986; Smits and Lefebvre, 2003; Swiderski and Solursh, 1992).