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 digestion digestion in small intestine digestive glands and their secretions alimentary canal

Most digestion and absorption takes place in 

  1. Stomach

  2. Caecum

  3. Small intestine

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

The small intestine is the primary site for both the chemical digestion of food and the absorption of nutrients into the bloodstream. While the stomach begins protein digestion, the vast majority of nutrient uptake occurs in the small intestine.

Multiple choice bio-chemistry digestion digestion in small intestine digestive glands and their secretions alimentary canal

Vomiting is related to disturbance in

  1. Stomach sometimes duodenum

  2. Hypothalamus

  3. Gastrointestinal tract

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

Vomiting is a reflex action typically triggered by irritation or distension of the stomach or the upper small intestine (duodenum). It is controlled by the vomiting center in the medulla oblongata, not the hypothalamus.

Multiple choice bio-chemistry digestion digestion in small intestine digestive glands and their secretions alimentary canal

Aggregates of lymphoid tissue present in distal portion of small intestine are known as 

  1. Villi

  2. Rugae

  3. Choroid plexus

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

Peyer's patches are organized lymphoid follicles found in the submucosa of the ileum, which is the distal portion of the small intestine. They play a critical role in immune surveillance of the intestinal lumen.

Multiple choice bio-chemistry digestion digestion in small intestine digestive glands and their secretions alimentary canal

Absence of enzyme in small intestine will severely affect digestion of proteins

  1. Maltase

  2. Lipase

  3. Enterokinase

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

Enterokinase (also known as enteropeptidase) is an enzyme that activates trypsinogen into trypsin. Without trypsin, other pancreatic proteases cannot be activated, leading to a severe failure in protein digestion.

Multiple choice bio-chemistry digestion digestion in small intestine digestive glands and their secretions alimentary canal

In jejunum, which of the following enzymes is required for the digestion of amino acid containing compounds?

  1. Chymotrypsin

  2. Pepsin

  3. Trypsin

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

Peptidases are the intestinal proteases, which act on peptides as follows:
$Polypeptide\xrightarrow[Alkaline \,medium]{Polypeptidase} Dipeptides$


$Dipeptide\xrightarrow[Dipeptidase]{Alkaline \,medium} Amino acids$
Pepsin, trypsin, and chymotrypsin, etc are aminopeptidases, which act upon amino groups of the peptide bond. 
Thus the correct answer is option D.

Multiple choice bio-chemistry digestion digestion in small intestine digestive glands and their secretions alimentary canal

If the inner surface of the ileum in the human small intestine was smooth, rather than being folded and subdivided into vilii, which of the following statements would be true? 

  1. The rate of absorption of digested food molecules would be higher, because the digested food would pass more easily through the digestive tract.

  2. Digestion would not be as effective, because there would be fewer cells secreting trypsin (a protein-digesting enzyme).

  3. Humans would have needed to evolve a much longer small intestine to absorb sufficient nutrients from their food.

  4. Humans would not be able to survive, because the digestive tract would be more susceptible to damage.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The correct answer is (c).

Multiple choice bio-chemistry digestion digestion in small intestine digestive glands and their secretions alimentary canal

Which of the following statements is false?

  1. The breakdown of most of biomacromolecules occurs in duodenum.

  2. Simple substances (digested foods) are absorbed in the jejunum and ileum.

  3. Significant digestive activity occurs in large intestine.

  4. Undigested and unabsorbed substances are passed on to the large intestine.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The correct answer is (c).