Biology · Science General

Human Digestive System

2,002 Questions

The human digestive system explores the breakdown of biomacromolecules, covering organs from the stomach to the small intestine. It involves physiological processes like chyme movement, pH levels, and nutrient absorption in the gut. These fundamental biology concepts are regularly featured in medical and general science competitive exams.

Small intestine functionsBiomacromolecule breakdownStomach and digestionIntestinal bacteria

Human Digestive System Questions

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Fats in the stomach is inhibited. This inhibition is due to

  1. Presence of fat

  2. Non stimulation of vagus nerve

  3. Slow digestion of fat

  4. Release of enterogastron
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  •  In the digestive environment, proteins, carbohydrates are initially attacked by enzymes produced by your salivary glands and stomach. And then it attacks fats.
  • However, effective enzymatic breakdown of fats requires emulsification by bile acids, a process that does not occur until fats leave your stomach and enter your small intestine. Hence, Fats in the stomach is inhibited. This inhibition is due to the slow digestion of fat. So, the correct answer is 'Slow
    digestion of fat'.

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Assertion  :  The main part of carbohydrate digestion
                      takes place in small intestine.

Reason    :    Here pancreatic amylase converts
                       carbohydrates into lactose


  1. If both the assertion and the reason are true and the reason

    is a correct explanation of the assertion

  2. If both the assertion and reason are true but the reason is

    not a correct explanation of the assertion

  3. If the assertion is true but the reason is false

  4. If both the assertion and reason are false

  5. If the assertion is false but reason is true
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In small intestine Pancreatic amylase converts starch and dextrose into maltoses and small intestine is main site for digestion of carbohydrates.

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Fatty acid and glycerol are first taken up from alimentary
canal by

  1. villi

  2. Blood capillaries

  3. Hepatic portal vein

  4. Lymph vessels
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Generally, fatty acids upto a chain length of 10 carbon atom are primarily absorbed through the blood capillaries, but those with higher chain length through lymphatic route (lymph vessels).

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Pancreatic juice and bile are poured through

  1. A common area into duodenum

  2. Two distinct ducts into duodenum

  3. A common duct into ileum

  4. Two distinct ducts into ileum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pancreatic juice and bile both empty into the duodenum. They typically join to form the common bile duct or hepatopancreatic duct before entering the duodenum at the major duodenal papilla.

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Most of the fat digestion occurs in

  1. Rectum

  2. Stomach

  3. Duodenum

  4. Small intestine
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Digestion of fat begins in duodenum with the help of pancreatic lipase but cannot be completed there because of its small size. Further it is component of small intestine. In infants some digestion occurs in stomach.

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Most of the digestion of lipids in humans takes place in

  1. mouth

  2. stomach

  3. small intestine

  4. colon
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  • Most lipids that you consume in your diet are fats. Some digestion occurs in your mouth and the stomach but mostly takes place in the small intestine. The purpose of the small intestine is to finish digestion and absorb nutrients. The small intestine is where most chemical digestion takes place. 
  • Many of the digestive enzymes that act in the small intestine are secreted by the pancreas and liver and enter the small intestine via the pancreatic duct. Hence, most of the digestion of lipids in humans takes place in the small intestine.
So, the correct answer is 'small intestine'.

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Which of the following associations is incorrect?

  1. Protein - trypsin

  2. Starch - amylase

  3. Fat - lipase

  4. Maltose - pepsin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • Trypsin is produced in the pancreas as an inactive protease trypsinogen. It is a protease found in the digestive system of many vertebrates, where it hydrolyses protein.
  • Amylase is a protein produced by the pancreas and by glands in and around mouth and throat. It helps you break down carbohydrates and starches into sugar.
  • Lipase is a protein produced by the pancreas. It is an enzyme that catalyses the hydrolysis of fats.
  • Pepsin is an endopeptidase produced in the stomach. It breaks down proteins into smaller peptides. Hence, the incorrect association is maltose-pepsin.
So, the correct answer is 'Maltose-pepsin'.

Multiple choice biology digestion and absorption digestion in small intestine digestive glands and their secretions alimentary canal

Digestive enzymes are released by pancreas and bile is released by liver in response to the hormone :-

  1. insulin

  2. zymogen

  3. secretin

  4. cholecystokinin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

CCK is in the duodenum and stimulates the release of digestive enzymes in the pancreas and stimulates the emptying of bile in the gallbladder. This hormone is secreted in response to the fat in the chyme

So, the correct answer is 'Cholecystokinin'