User:Jeeva/Assignment on STOMACH OF VERTEBRATES
Comparative anatomy of stomach.
- Agnatha and amphioxus.
Living agnathans have no definite stomach .The digestive tract one long tube from mouth to vest exhibiting no gross differentiation of esophagus stomach, or intestine .The epithelium of agnathan tract is a single layer of cells including goblet cells that secete mucus and flask shaped cells that synthsise proteolytic (protein splitting)enzymes.The base of each cell is in contact with the underlying vascularised layer of mucosa ,from which they recieve nourishment.
The stomach of fishes display a wide variety of shapes, and the epithelium is almost stiaght ,sharks exhibit the more common j shaped . The gar stomach is almost straight ,sharks exhibit the more common j shaped.Th entire stomach of some teleosts is one large ceacum .Chimeras and lung