Digestive System in Humans

Todays topic is Digestive System in Humans for ICSC biology class 6.Students can also check The Human Digestive System topic for biology class 12.

The food we eat is not absorbed by the body until it is broken down properly. This process of breaking down of food into simpler form so that it can be absorbed by the body is known as digestion.

Why do we need food?

We need food to -

1.get energy

2.grow and repair the body cells.

3. protect the body from many diseases.

What are nutrients?

These are the chemical substances that provide nourishment to the body.

There are seven nutrients that are essential for a healthy diet plan. These are -

1.Carbohydrates - They give us energy and are also known as energy giving food. For example - rice, potatoes,bread, chapati etc.

2.Fats - They also give energy but they provide more energy than carbohydrates. For example - ghee, oil, butter etc.

3.Proteins - They help in the growth and development of the body and are known as growth food. They also help to repair the damaged body cells. For example - eggs, pulses, soya, meat etc.

4.Vitamins - They protect our body from certain diseases and are also known as protective food. These are of two types -

*Fat soluble vitamins They can be stored in the body. For example - Vitamin A, D, E and K

*Water soluble vitamins These can't be stored in the body and moves out from the body with the urine.For example - Vitamin C and Vitamin B

Fruits, vegetables , milk and milk products are good sources of vitamins etc.

5.Minerals - Minerals are also known as balancing food as they help in maintaining good health and for the proper growth of the body.Such as calcium is important for strong bones and teeth.Iron is required for the formation of haemoglobin.For example - fruits, vegetables, fish, meat etc.

Both vitamins and minerals are needed in small amounts by the body.

6.Roughage - The fibrous part of the food that can't be digested by the body is known as roughage. It makes you feel full for a longer time. Hence help to keep you fit by preventing overeating. It also prevents constipation. For example - whole grains, fruits, vegetables, etc.

7.Water - We should drink at least 7-8 glasses of water. It helps in cleaning our body by removing toxins. All the reactions in the body take place in the presence of water.

What are the important steps in the process of nutrition?

1.Ingestion - The process of intake of food is known as ingestion.

2.Digestion - The process of breaking down of food particles into simpler form so that it can be absorbed easily by the body is known as digestion.

3.Absorption - The process in which the digested food passes to the blood from the intestine is known as absorption.

4.Assimilation - The process in which the absorbed minerals are utilized by the body for different functions is known as assimilation.

5.Egestion - The process of removal of undigested solid part of the food is known as egestion.

Digestive System in Humans

Digestive system in humans consists of two parts i.e

1.Alimentary canal

2.Associated digestive glands

1.Alimentary canal - It is a long tube that extends between the mouth and the anus. It consists of the following parts -

(a) Mouth - It is also known as buccal cavity. It is a small slit like opening. Food is ingested only through the mouth.The process of digestion of food starts in the mouth . Saliva in the food helps in the digestion of the food partially by converting starch into sugar.

*Teeth -To read topic of teeth click on this link : https://lessonstobelearneda-z.blogspot.com/2022/01/structure-of-teeth-teeth-are-very.html

*Tongue - It is a thick and muscular organ. It consists of taste buds that help in distinguishing between different flavours and tastes.

(b) Pharynx - It is found at the back of the throat. It extends from the mouth and nose up to the throat. It joins the food pipe or oesophagus with the nasal cavities. It has three parts or portions -

*upper - the passage for air

*middle - the passage for food and air

*lower - the passage for food

(c) Food pipe or oesophagus - It extends from the pharynx up to the stomach. It helps in passing or carrying food from the mouth to the stomach. Food is pushed down the oesophagus with the help of muscular contractions. This type of movement of food is known as peristalsis.

(d)Stomach - It is found on the left side of the abdomen and is J-shaped.The digestion of proteins present in the food starts in the stomach. Digestive glands in the stomach secretes digestive juices such as HCl and rennin that mix with the food to convert it into a paste called chyme which passes into the small intestine to be digested further.

(e) Small Intestine - It occurs in the form of a coiled tube and is the largest part of the alimentary canal. Food passes from the stomach to the alimentary canal to be digested further. Finger like projections called villi are present in the small intestine to increase the surface area of small intestine for the process of absorption of food. Small intestine consists of the following three parts -

*Duodenum - It is the anterior part of the small intestine.

*Jejunum - It is the middle part of the small intestine.

*Ileum - It is the posterior part of the small intestine.

The food is digested completely in the small intestine. This digested food is absorbed by the blood and the undigested food passes to the large intestine.

(f) Large Intestine - The undigested food passes from the small intestine to the large intestine. It has the following three parts -

*Caecum - The undigested part of food is further mixed with bacteria to form faeces.

*Colon - Water is absorbed from the undigested part of the food to form faeces.

*Rectum - It helps in storing faeces.

Rectum is followed by anus from which the undigested part of the food is thrown out of the body as excreta.

To check part 2 of the chapter click on this link : https://lessonstobelearneda-z.blogspot.com/2022/03/digestion-of-food.html

Hope you liked this topic Digestive System in Humans for ICSC biology class 6.Please share it and comment if you want article on any other topic.You may practice this topic using Worksheets for Science related to this topic.

Note : To follow this chapter only just check the link given for part 2 of the chapter.

Related Topics

The Flower

Fertilization in Plants

The Leaf

The Cell

Matter|Matter Properties

Air and the atmosphere

ICSC|Class 6|Chemistry|Water

How many muscles are in a human's body?

ECG - How to read?

What is blood pressure lower number?