(a) Describe with the aid of a diagram the stomach of a named ruminant. (b) compartment of the stomach of a ruminant.

(a) Stomach of a ruminant: Cattle (cow)

The stomach of a cow is compound and consists of four compartments:

1. Rumen (paunch): This is the first and largest compartment. Its inner lining bears numerous tongue-like projections called papillae, giving it a soft towel-like appearance. It temporarily stores feed and is the main site of microbial fermentation of cellulose.
2. Reticulum (honeycomb): This is the second compartment, lying close to the rumen. Its mucosal lining forms hexagonal chambers, giving it a honeycomb appearance. It helps in the formation and regurgitation of cud for re-chewing.
3. Omasum (manyplies): This is the third and smallest compartment. It contains many leaf-like folds or laminae, which help to grind food and absorb water.
4. Abomasum: This is the fourth and last compartment. It is the glandular or true stomach, comparable with the simple stomach of monogastric animals. It secretes gastric juice for chemical digestion and leads into the small intestine.

(b) Functions of the rumen, the first compartment of the ruminant stomach

1. It is the main site of fermentation of feed by micro-organisms.
2. It temporarily stores feed before regurgitation for proper re-chewing.
3. Cellulose and other fibrous materials are broken down by micro-organisms.
4. Volatile fatty acids and gases are produced during fermentation.
5. Volatile fatty acids are absorbed through the wall of the rumen.
6. Some vitamins, especially vitamin B complex, are synthesised by micro-organisms in the rumen.