HUMAN DIGESTIVE SYSTEM BY MANI MA'AM

 

HUMAN DIGESTIVE SYSTEM

DIGESTION:-The breakdown of large insoluble food molecules into small soluble molecules to be absorbed in body cells are called digestion.

DIGESTIVE SYSTEM:-The system is responsible for breakdown of complex non absorbable components like:-

Ø Fats

Ø Protein

Ø Carbohydrates

Into smallest absorbable components like:- fatty acid, amino acid and glucose

STEPS OF DIGESTION:-

1.     Ingestion:- It is the process to inject the food to our alimentary canal.

2.     Propulsion:- It is the process of  movement of food items through the digestive tract.

3.     Digestion:- This is both chemical and physical process in which the food is break down into small absorbable components of food.

4.     Absorption:- This is the process to absorb the all useful nutrients.

5.     Elimination/Egestion: - This is the process of removing waste material from human body.

STEPS OF DIGESTION IN ALIMENTARY CANAL:-

MOUTH:-The digestive process starts in our mouth when we chew. Our salivary glands make saliva, a digestive juice, which moistens food so it moves more easily through your oesophagus into your stomach. Saliva also has SALIVARY AMYLASE enzyme that break down starches in our food.

OESOPHAGUS:- By peristalsis movement the food move from mouth to our stomach through oesophagus.

STOMACH:-  Food enters the stomach through a muscular valve called the lower esophageal sphincter. The stomach secretes acid and enzymes that digest food.

NOTE:- For prevention of stomach wall from acid(HCL)  a protective layer over the lining epithelium of the stomach cavity have mucus.

SMALL INTESTINE:- The small intestine is categorized in three parts;

1. The duodenum

2.  The jejunum

3. The ileum

When food enters the duodenum, the pancreas releases enzymes to help break down fat, protein and carbohydrate and convert the food in alkaline medium. The gall bladder releases bile, which has been produced by the liver, to help further break fats down into a form that can be absorbed by the intestines.

The small intestine is lined with finger-like projections, called villi, which provide a very large surface area facilitating the absorption of nutrients, including carbohydrates, proteins and fats, into the bloodstream.

The small intestine also plays a key role in regulating blood glucose levels .The small intestine contains a number of receptive cells which detect the presence of macronutrients and secrete hormones which instructs the pancreas on how much insulin and glucagon to release.

The colon (large intestine):- The final stage of the digestive system is the colon (large intestine) which absorbs water and salts before the remains are passed out of the rectum as faeces. The colon can also help to absorb remaining carbohydrate and some fats.

ANUS:- By anus waste product of our body are passed out.

                                                                         BY MANI MA'AM(M.SC, B.ED)