Question

Please Answer all parts thank you!

1) Explain how the following structural features are linked to the primary digestive function of each region of the small intestine:

a. duodenal gland in the duodenum

b. prominent intestinal villi in the jejunum

c. aggregated lymphoid nodules in the ileum

2) The intestinal villi and brush border(microvilli),common in the small intestine, are absent in the large intestine. What does this absence tell you about the digestive function of the large intestine.

Answer 1

Answer 1(a) - duodenum glands is also called as Brunner's glands. It is found in the duodenum above the hepatopancreatic sphinctor. It secretes mucus rich alkaline scretions that is bicarbonates in order to ;

• protect duodenum from acidic content of chyme ,which is introduced into the duodenum from the stomach.
• provides an alkaline condition for intestinal enzymes to become active, as intestinal enzymes works in alkaline medium thus enabling absorption to take place.
• It also lubricate the intestinal walls.

Anawer 1(b) - villi are specialised structures found in the small intestine .they are very thin and so help in absorption of food as they have large surface area which helps in absorption of big molecules like fats.

Answer 1 (c)- intestinal lumen is exposed to certain kind of pathogenic microorganisms that is foreign bodies like bacterias viruses,which can cause gastrointestinal problems. So these lymphoid nodules often called as Peyer's patches found in the ilium which activates the immune system when any foreign body enters .these cells traps the pathogenic microorganisms and also destroy them.

Answer 2- large intestine doesn't contain microvilli as so there is no absorption takes place in the large intestine because there is less space for absorbtion of food.only water, electrolyte like sodium, potassium ,certain drugs are absorbed in the large intestine.