Human Digestive System Notes for SSC Exams

The human digestive system breaks the food we eat into small substances that the body can absorb and use. SSC General Science asks about the organs, the glands, the enzymes and the part where each food is digested. These human digestive system notes for SSC explain the whole path of food and the enzymes table in simple language with practice questions.

Path of Food in the Body

The digestive system is a long tube called the alimentary canal, which is about 8 to 9 metres long, and it has some glands attached to it.

1. Mouth: food is chewed and mixed with saliva.
2. Oesophagus (food pipe): food is pushed to the stomach by wave-like movements called peristalsis.
3. Stomach: food is mixed with acid and enzymes and becomes a thick liquid.
4. Small intestine: digestion is completed and nutrients are absorbed.
5. Large intestine: water is absorbed and the waste is made into faeces.
6. Rectum and anus: the waste leaves the body.

Digestion in Each Part

Digestive Glands

Important Digestive Enzymes

Final Products of Digestion

• Carbohydrates are changed into glucose.
• Proteins are changed into amino acids.
• Fats are changed into fatty acids and glycerol.

Absorption

The inner wall of the small intestine has tiny finger-like parts called villi. They increase the surface area and absorb digested food into the blood. The small intestine is the longest part of the alimentary canal, about 6 to 7 metres long, and has three parts: duodenum, jejunum and ileum.

Interesting Facts for Exams

• The liver is the largest gland of the body.
• The pancreas is both an exocrine and an endocrine gland.
• The pH of the gastric juice in the stomach is very low, about 1.5 to 2.
• The appendix is a small organ attached to the large intestine and has no important digestive function in humans.
• Bile is made in the liver, but it is stored in the gall bladder.

Common Disorders

Quick Tips

• Learn the enzyme table with food and product, because it is the most asked part.
• Remember that bile has no enzyme but helps in digestion of fats.
• Link the organs with their length, such as the small intestine as the longest part.
• Do not mix the liver (makes bile) with the gall bladder (stores bile).

Quick Revision Points

• Digestion of starch starts in the mouth.
• Digestion of protein starts in the stomach with pepsin.
• Digestion is completed and food is absorbed in the small intestine.
• The liver is the largest gland, and it makes bile.
• Water is absorbed in the large intestine.

Practice Questions With Answers

1. In which part does the digestion of starch begin?
   Answer: Mouth
2. Which enzyme digests proteins in the stomach?
   Answer: Pepsin
3. Which is the largest gland of the human body?
   Answer: Liver
4. Where is bile stored?
   Answer: Gall bladder
5. In which part is most of the food absorbed?
   Answer: Small intestine
6. What is the end product of carbohydrate digestion?
   Answer: Glucose
7. Which enzyme is present in saliva?
   Answer: Salivary amylase (ptyalin)
8. What are the finger-like parts of the small intestine called?
   Answer: Villi
9. Which gland makes both digestive juice and insulin?
   Answer: Pancreas
10. The yellow colour of the skin in jaundice is due to which organ problem?
    Answer: Liver

How to Practise This Chapter

Draw the digestive system and label each part once, and then learn the enzymes table. Solve ten questions daily from the practice papers and the free SSC quizzes and check the previous year papers page. Read the previous chapter, Vitamins and Deficiency Diseases, and see all the chapters on the General Science notes page. Also read the General Awareness notes.

Frequently Asked Questions

What is the digestive system?

The digestive system is the group of organs that break food into small parts, absorb the nutrients and remove the waste from the body.

What are the main organs of the digestive system?

The main organs are the mouth, oesophagus, stomach, small intestine, large intestine, rectum and anus. The liver, gall bladder and pancreas help in digestion.

Where does digestion of proteins start?

Digestion of proteins starts in the stomach by the enzyme pepsin in the presence of hydrochloric acid.

What is the function of bile?

Bile breaks big fat drops into small ones, so that the enzyme lipase can digest them easily. It is made in the liver and stored in the gall bladder.

Which is the longest part of the alimentary canal?

The small intestine is the longest part, about 6 to 7 metres long.

Where does absorption of food take place?

Most food is absorbed in the small intestine through villi, and water is absorbed in the large intestine.

What is peristalsis?

Peristalsis is the wave-like movement of the muscles of the food pipe and intestine that pushes the food forward.

Why is the pancreas an important gland?

It makes pancreatic juice for digesting carbohydrates, proteins and fats, and also makes the hormone insulin.

What are the final products of digestion?

Carbohydrates become glucose, proteins become amino acids, and fats become fatty acids and glycerol.

What is jaundice?

Jaundice is a liver problem in which the skin and eyes turn yellow because of too much bilirubin in the blood.

How can I remember the enzymes easily?

Learn each enzyme with the organ where it is made, the food it digests and the final product, and revise the table every week.

How many questions come from the digestive system in SSC exams?

Usually one question comes from the human body systems in SSC General Science papers, but the number changes from year to year.