Biology ยท 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

Villi present on the inner lining of the intestinal wall

  1. Secretes enzymes for digestion

  2. Secretes hormones

  3. Decreases the surface area for absorption

  4. Increases the surface area for absorption
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Intestinal villi are small, finger-like projections that protrude from the epithelial lining of the intestinal wall. Villi increase the internal surface area of the intestinal walls. Increased surface area allows for increased intestinal wall area that is available for absorption.

Multiple choice

Where is bile produced?

  1. Gall bladder

  2. Blood

  3. Liver

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

Bile is produced by liver and is stored in gall bladder.

Multiple choice

If salivary amylase is lacking in the saliva, which of the following events in the mouth cavity will be affected?

  1. Proteins break down into amino acids

  2. Starch breaking down into sugars

  3. Fats breaking down into fatty acids and sugar

  4. Absorption of vitamins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Amylase is an enzyme that catalyzes the hydrolysis of starch into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion. Foods that contain large amounts of starch but little sugar, such as rice and potatoes, may acquire a slightly sweet taste as they are chewed because amylase degrades some of their starch into sugar.

Multiple choice

Peristalsis is a series of wave-like muscle contractions that moves food to different processing stations in the digestive tract. It occurs in which part of the digestive tract?

  1. In the large intestine

  2. In the small intestine

  3. In the stomach

  4. In the esophagus

  5. In the mouth
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

After being chewed and swallowed, the food enters the esophagus. It uses rhythmic, wave-like muscle movements (called peristalsis) to force food from the throat into the stomach. This muscle movement gives us the ability to eat or drink even when we are upside-down.

Multiple choice

Kallikreins are a subgroup of serine proteases, enzymes capable of cleaving peptide bonds in proteins present in the food. Which of the following digestive ducts participates in ion and water transport and secretes kallikrein?

  1. An intercalated duct

  2. A striated duct

  3. An excretory intralobular duct

  4. Intralobular ducts

  5. Interlobular ducts
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The striated duct is well developed in the submandibular gland. The epithelium of the striated duct participates in ion and water transport and secretes kallikrein. A segment of this duct is lined by cuboidal-to-columnar epithelial cells with basal infoldings containing numerous mitochondria.

Multiple choice

Which of the following statements regarding the human digestion process is INCORRECT?

  1. The human gastrointestinal tract is around 9 meters long.

  2. The gastric phase occurs at the sight, thought and smell of food.

  3. The gastric phase is stimulated by distension of the stomach.

  4. Gastric acid is about 0.5% hydrochloric acid.

  5. Digestion begins in the mouth of an organism.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Different phases of digestion take place including the cephalic phase, gastric phase and intestinal phase. The cephalic phase occurs at the sight, thought and smell of food, which stimulate the cerebral cortex. Taste and smell stimuli are sent to the hypothalamus and medulla oblongata.

Multiple choice

Which of the following statements about gastric parietal cell antibodies [GPC] is true?

  1. GPC are found more frequently in gastric juice than in serum.

  2. GPC are diagnostic of pernicious anaemia.

  3. They are considered best in screening test for pernicious anaemia.

  4. They inhibit absorption of vitamin B12 in the ileum.

  5. They are usually of IgM isotype.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As they are not specific for pernicious anaemia, GPC must be interpreted in conjunction with low serum vitamin B12 level.