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 bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

Movement of alimentary canal does not help in slipping down of food is

  1. Peristalsis movement

  2. Pendular (segmentary) movement

  3. Both

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Certain muscular contraction of alimentary canal such as segmentary/pendular are responsible for churning and mixing of the food thoroughly with digestive juices not for propel.

Multiple choice bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

Which of the following organs absorbs food nutrients through villi?

  1. Small intestine

  2. Oesophagus

  3. Rectum

  4. Stomach
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The absorption is done in the small intestine with the help of villi which helps increase the surface area of the intestine, so as to store more digested food.

So, the correct option is 'small intestine'.

Multiple choice bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

Read the following statements and select the correct option.
Statement 1 : The human small intestine is the longest portion in the alimentary canal.
Statement 2 : Absorption of digested food requires a very large surface area. 

  1. Both statements 1 and 2 are correct.

  2. Statement 1 is correct but statement 2 is incorrect.

  3. Statement 1 is incorrect but Statement 2 is correct.

  4. Both statements 1 and 2 are incorrect.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct answer is (a).

Multiple choice bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

We eat food, which is composed of all the nutrients like carbohydrates, proteins, fats, vitamins, minerals and water. After digestion, these are absorbed in the form of glucose, amino acids, fatty acids, glycerol etc. What mechanisms are involved in absorption of digested food and water?

  1. Diffusion and osmosis respectively

  2. Osmosis and diffusion respectively

  3. Reverse osmosis and facilitated diffusion respectively

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Diffusion is a process in which the molecules intermingle due to their kinetic energy and movement of molecules is from higher concentration to lower concentration. Osmosis is a process in which the water molecules move from lower solute concentration to higher solute concentration through a semi-permeable membrane. Digested food can pass into the blood vessels in the wall of the small intestine through the process of diffusion and water present in the ingested food is absorbed by the process of osmosis. 

Multiple choice bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

Part of alimentary canal meant for reabsorption of water from chyle is

  1. Small intestine

  2. Colon

  3. Large intestine

  4. Rectum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The small intestine is meant for the reabsorption of water. Major absorption of water takes place in the intestine and further in the large intestine.

So, the correct option is 'small intestine'.

Multiple choice bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

A specialized structure in intestine that helps in absorption is

  1. Alveoli

  2. Villi

  3. Bowman's capsule

  4. Salivary glands

  5. Pyloric sphincter
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  1. The innermost layer lining the lumen of the alimentary canal is the mucosa.
  2. This layer forms irregular folds (rugae) in the stomach and small finger-like foldings called villi in the small intestine.
  3. The cells lining the villi produce numerous microscopic projections called microvilli giving a brush border appearance found on the apical surface of some epithelial cells. 
  4. These modifications increase the surface area enormously and help in secretion and absorptionHence, the specialized structure in the intestine that helps in absorption is villi.
So, the correct answer is 'villi'.
Multiple choice bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

What percentage of amino acids is absorbed in the small intestine?

  1. 15%

  2. 30%

  3. 100%

  4. 90-95%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Initiation of protein digestion starts in the stomach by pepsin but around 90-95% of protein is digested and absorbed in duodenum and jejunum of the small intestine in the form of amino acids by the action of enzymes trypsin, chymotrypsin and carboxypeptidases.

So the correct option is '90-95%'

Multiple choice bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

Which one of the following is not a step during digestion process?

  1. Ingestion

  2. Digestion

  3. Acid processing

  4. Absorption

  5. Elimination
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • The chemical breakdown of complex biological molecules into their component parts like lipids into fatty acids, proteins to individual amino acids, carbohydrates into simple sugars.
  • Digestion includes 5 phases :
  1. Ingestion.
  2. Movement.
  3.  Digestion.
  4.  Absorption. 
  5. Further digestion. Hence, the following step not involved during the digestion process is acid processing.
So, the correct answer is 'acid processing'.
Multiple choice bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

Absorption is defined as

  1. elimination of solid waste from the digestive system

  2. breakdown of foods by enzymatic action

  3. passage of nutrients from the gastrointestinal tract into the blood stream

  4. mechanical breakdown of fat
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

  • Absorption is the process by which the products of digestion are absorbed by the blood to be supplied to the rest of the body. 
  • During absorption, the digested products are transported into the blood or lymph through the mucous membrane. Hence, Absorption is defined as the passage of nutrients from the gastrointestinal tract into the bloodstream.
So, the correct answer is 'passage of nutrients from the gastrointestinal tract into the bloodstream'.

Multiple choice bio-chemistry food through digestive tract absorption of food absorption parts of the digestive system: structure and function

Most of the absorption of the products of digestion takes place in humans across the

  1. smooth wall of the large intestine

  2. fingerlike villi of the small intestine

  3. convoluted walls of the stomach

  4. squamous epithelium of the oesophagus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • The innermost layer lining the lumen of the alimentary canal is the mucosa. This layer forms irregular folds (rugae) in the stomach and small finger-like foldings called villi in the small intestine. 
  • The cells lining the villi produce numerous microscopic projections called microvilli giving a brush border appearance. These modifications increase the surface area enormously. 
  • Villi are supplied with a network of capillaries and a large lymph vessel called the lacteal. Hence, Most of the absorption of the products of digestion takes place in humans across the fingerlike villi of the small intestine
So, the correct answer is 'fingerlike villi of the small intestine'.
Multiple choice bio-chemistry digestive system of human absorption of food absorption parts of the digestive system: structure and function

$30\%$ starch is hydrolysed in Buccal cavity by which of the following enzymes?

  1. Pancreatic $\alpha$ -amylase

  2. Lipase

  3. Maltase

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

Salivary glands in your mouth (Buccal cavity) make salivary amylase, which begins the digestive process by breaking down starch when you chew your food, converting it into maltose, a smaller carbohydrate.

So the correct option is D, salivary amylase.

Multiple choice bio-chemistry digestion absorption of food absorption parts of the digestive system: structure and function

Which of the following stimulates the secretion of gastric juice?

  1. Gastrin

  2. Enterogastrone

  3. Secretin

  4. Hepatocrinin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gastrin is a peptide hormone, that stimulates secretion of gastric acid ($HCl$) by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the pyloric antrum of the stomach, duodenum and the pancreas.

Multiple choice bio-chemistry digestion absorption of food absorption parts of the digestive system: structure and function

Secretion of gastric juice is controlled by

  1. Gastrin

  2. Cholecystokinin

  3. Enterogastrone

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As food enters the confined space of the stomach, it starts applying pressure to the stomach wall distending it a bit. This distention causes the stomach to release gastrin, which stimulates the gastric glands to secrete more gastric juice.