#zoology # Biology
A true blood vascular system is absent. In star fish, this system circulates digested food to all body parts. It can be studied under two parts.
1. Haemal system: It is reduced. It has spaces which do not show epithelial lining. These spaces inter-communicate with each other. The haemal channels are enclosed in the coelomic spaces of the perehaemal system. They contain coebmic fluids.
a)The mouth is surrounded by a oral haemal ring.
b) From the oral haemal sinus arises radial haemal sinuses. Each one enters into one arm.
c)The oral haemal ring is connected with the aboral haemal ring through the axial gland. A pair of gastric haemal tufts arise from the sinus in the region of cardiac stomach wall. They open into the haemal plexus of the axial gland.
These haemal channels are in fact not true blood vessels. They contain fluid which helps in the circulation and distribution of digested food materials.
Негізгі бет Hemal system of echinoderms (star fish)
Пікірлер: 2