LARGE INTESTINE -
More wider. Arranged around small intestine in the form of ?. It is 1.5 m long. Villi & microvilli absent.
It shows 3 parts Ceacum, colon & rectum.
(i) Ceacum -
6 cm. wide. At Ileo ceacal junction, Ileoceacal valve is present.
Ceacum bears 8 cm. long vermiform appendix. (vestigeal organ), made up of lymphoid tissue.
Infection of appendix is appendicitis its removal is must i.e. appendictomy.
Ceacum is large in herbivorous for digestion & absorption of cellulose. So symbiotic bacteria and symbiotic protozoa are present.
(ii) Colon -
It is sacculated in appearance due to a series of constriction. It shows ascending colon, transverse colon, de- scending colon & sigmoid or pelvic colon.
In it 3 long bends Taeniae present, around these sac like haustra present having decomposer type of bacteria.
Ammonia is formed in it.
Here undigested food is converted into faeces. In children bacteria develop after 10 days of birth.
(iii) Rectum -
15-20 cm. long. It has longest folds and large blood vessels.
It leads to 2.5 cm. anal canal which open out side by anus.
Some time due to enlargement of rectal veins piles are caused.
Anus is guarded by two sphinctors, inner of involuntary muscles and external of voluntary muscles.
In Aves Bursa febrichi is cloacal thymus.