Digestive System

The Digestive System is one of the vital systems of all living beings. The food we eat gets converted to the much needed energy only due to our digestive system. All the organs of this system work in perfect synchronization to make sure that maximum nutrition is extracted from this food and passed on to our Circulatory System.

These Worksheets aims at strengthening a student’s Science concepts about the ‘Human Digestive System’.  Other than fill in the blanks and definitions, it also includes diagrammatical questions that makes it fun and interesting. This worksheet can be used by tutors as a ‘Diagnostic Assessment’ to plan and design a Grade 8 student’s future learning sessions on this topic.

It can also be used as an ‘End of Topic Test’ to assess a student’s assimilated knowledge about the topic.

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What are the organs of the digestive system?

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Pharynx

The pharynx acts as a passage for the chewed food from the mouth to the esophagus. It has a flap of tissue known as the epiglottis preventing the food from getting into the wind pipe and helps us from getting choked while we eat.

Esophagus or Food Pipe

The esophagus is a tube joining the pharynx to the stomach. It is made of flexible muscle to help pushing of food easily. It carries swallowed food down its long tube and pushes it to the stomach.

Stomach

The stomach is a thick-wall made of muscle in the form of a bag that is located on the left side of the abdominal cavity. It is the largest part of our digestive system. Stomach acts as a storage place for food. And slowly digests food. It gets food from the food pipe and sends it to the small intestine. The stomach has digestive acids which help reduce food into further absorbable substances. Mucous protects the inner walls of the stomach. This can otherwise get damaged while digesting food. Because the acid reacts with the bacteria and kills it that enters our body with food. The digestive enzymes break down proteins into simpler substances.

Small Intestine

The small intestine is just named small. But it is the longest part our digestive system. It is made in such a way that it is highly coiled; it’s quite thin tubular form but still about 7.5 meters long. (The length of the small intestine depends on the diet of the organism.) A major proportion of digestion takes place in the small intestines. Nutrients get digested here. The walls of the small intestine also secrete juices for digesting food. The enzymes in the intestine convert the carbohydrates into glucose, proteins to amino acids and fats into fatty acids and glycerol.

Liver

The liver releases bile. This neutralizes the acidity level of the food. The pancreatic juice digests the proteins and lipids. Once the food is broken down into the simple particles, it is ready to be absorbed by the body.  The absorbed food is then carried to different parts of the body through the blood vessels for cell activities.

Large Intestine

The large intestine is a thicker tube than the small intestine. The large intestine absorbs water and left over nutrients from the remaining food with the help of many bacteria in it. The remaining food waste passes into the rectum, where it is ready to get out as semi-solid wastes. Feces then are excreted by the body through the anus.

Sample Questions

Q1. Identify organs involved in digestion –

A. I deliver food to stomach by means of series of muscular contractions called ‘Peristalsis’.____________
B. I act as a hollow container that holds food and secrete HCL.____________
C. I am the largest gland in the body and helps in bile secretion.____________
D. I am responsible to produce a watery secretion that helps to moisten food and begins the digestion of carbohydrates.____________
E. I am a long muscular tube and helps in absorption of food. I have millions of VILLI that increase the food absorption area._____________

Q2. Define these terms –

A. Digestion :__________________________________________________
B. Absorption :_________________________________________________
C. Bile Juice:__________________________________________________
D. Mechanical Digestion :__________________________________________
E. Peristalsis :__________________________________________________

Check Point

I. Fill in the blanks –

1. The ……………………..……………is the long tube through which the food that we eat is passed.
2. The flap of tissue known as the ……………… present in pharynx prevents food from entering into the wide pipe.
3. The enzymes in the intestine convert the ………………. into glucose, proteins to …………….. and fats into fatty acids and glycerol.
4. The liver releases ………. juice which neutralizes the acidic food received from the stomach and also converts the fat.
5. The ……………… ……… digests the proteins and lipids.

II. State True or False –

1. The digestive system of is a system of organs working together to eliminate waste products out of the body.
2. The esophagus is a tube joining the pharynx to the stomach made of flexible muscle to ease pushing of food.
3. Mucous protects the lining of the stomach while acid kills bacteria that enter the body along with the food.
4. The small intestine is the smallest part of the human digestive system.
5. A major proportion of digestion takes place in the large intestines.

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