Page 58 - Biology Form Two

Biology for Secondary Schools

Duodenum Omasum
Oesophagus

FOR ONLINE READING ONLY
Rumen

Pyloric sphincter
Reticulum
Abomasum

Figure 2.8: Internal structure of the ruminant’s digestive system

When the ruminant animal is resting, that contain hydrochloric acid and
the food stored in the rumen is brought digestive enzymes. The hydrochloric
back to the mouth (regurgitated) acid kills harmful bacteria and other
periodically for further chewing. germs that entered the body with
The regurgitated food is thoroughly the food. The gastric juices contain

chewed, rolled and swallowed again. enzymes that digest carbohydrates,
Instead of the food passing again into cellulose, proteins, and fats. From this
the rumen, it passes to the reticulum point, the digestion process continues
which is the second chamber of the as in human beings.
stomach. In the reticulum, the food
is mixed thoroughly with water and Differences between the digestive
becomes soft, watery, and less greenish system of human beings and that of
compared to food in the rumen. From ruminants
the reticulum, the food passes to the
third chamber of the stomach called the The digestive system of a ruminant is
omasum, which is the smallest among different from that of a human being.
the four chambers of the stomach. In Ruminants have a more elaborate system
the omasum, the food is further mixed to enable cellulose digestion. Like other
and some water is absorbed from it. In mammals, including human beings, the

this chamber, the food is in the form of digestive system of ruminants has different
fine particles and less watery. Then, the parts including the mouth, pharynx,
food proceeds to the fourth chamber of oesophagus, stomach, duodenum, ileum,
the stomach, the abomasum. This is the colon, caecum, appendix, rectum, and
true stomach similar to that of other
mammals, including human beings. anus. However, the structure of the
The abomasum secretes gastric juices digestive system of ruminants differs from

52 Student’s Book - Form Two

05/10/2024 15:36:23
BIOLOGY FORM 2 NEW.indd 52 05/10/2024 15:36:23
BIOLOGY FORM 2 NEW.indd 52