Question

200 words Choose one portion of the digestive system and explain its individual function and how it contributes to the breakdown and/or absorption of food.

Please try to pick a new portion, with minimal students repeating the same area.

Answer 1

The digestive system is responsible for the digestion and breakdown of the food that we eat as well as elimination of waste products from the body in the form of feces. The digestive system consists of mouth, oesophagus, stomach, large intestine and small intestine as the main organs or digestion and tongue, salivary gland, liver, gall bladder and pancreas as the accessory digestive organs.
Today I will choose the small intestine and describe its structure and functions.
Small intestine is divided into deuodenum, jejunum and ileum. The deuodenum is the first part of intestine that is connected to the pylorus of the stomach. It receives gastric chyme from the stomach. Duodenum receives pancreatic juices in response to cholecystokinin secreted by small intestine as well as bile from the gall bladder. Small intestine also secretes secretin which stimukates bicarbonate products and neutralize the gastric chyme.
Pancreatic enzyme trypsin and chemotrypsin helps in breakdown of proteins. Pancreatic lipase breaks down the triglycerides and lipids into fatty acid. Pancreatic amylase breaksdown carbohydrates into monosachharides.
The nutrients broken down in the small intestine are reabsorbed through the wall of the  small intestine and passed on to blood through diffusion and active transport. The intestinal wall contains plicae circularis, villi abd microvilli that results in increasing the surface area for absorption.
Some of the important nutrients absorbed by the small intestine are iron, vitamin B12, folate, bile salt, water, lipids, amino acid, glucose, fructose.
The food then passes from the ileum to the large intestine.