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 what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

Ptyalin cannot work in stomach, because it be comes _____________.

  1. Inactive due to HCl

  2. Inactive due to Renin

  3. Inactive due to Pepsin

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

Ptyalin (salivary amylase) functions in an alkaline or neutral environment. When it reaches the stomach, the highly acidic environment created by HCl denatures the enzyme, rendering it inactive.

Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

Which of the following is the stomach part in which herbivores secretes the grass which is swallowed quickly? 

  1. Lumen

  2. Pyloric

  3. Rumen

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

Vertebrates lack the ability to hydrolyse the beta glycosidic bond of plant cellulose due to the lack of the enzyme cellulase. Thus, ruminants must completely depend on the microbial flora, present in the rumen or hindgut, to digest cellulose. Digestion of food in the rumen is primarily carried out by the rumen microflora. Since, the environment inside a rumen is anaerobic, most of these microbial species are obligate or facultative anaerobes that can decompose complex plant material, such as cellulose, hemicellulose, starch, and proteins. As bacteria conduct fermentation in the rumen, they consume approximately 10% of the carbon, 60% of the phosphorus, and 80% of the nitrogen that the ruminant ingests. To reclaim these nutrients, the ruminant then digests the bacteria in the abomasum. The enzyme lysozyme has adapted to facilitate digestion of bacteria in the ruminant abomasum. Pancreatic ribonuclease also degrades bacterial RNA in the ruminant small intestine as a source of nitrogen. 

Therefore, the correct answer is option C.

Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

The partially digested food in the stomach of ruminants is called as

  1. Bud

  2. Cud

  3. Ruminant

  4. Rumen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • Rumination is also called second chewing. 
  • Ruminant stomach: The stomach of a ruminant is divided into four chambers – the rumen, reticulum, omasum and abomasum. 
  • The process of digestion is as follows: The food is chewed and swallowed quickly and passed into the first stomach called Rumen. The microorganisms help in breaking down the food. Digestive juices of the rumen partially digest the food. The partially digested food in the rumen is called cud. Hence, The partially digested food in the stomach of ruminants is called cud.
So, the correct answer is 'cud'.

Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

The sac like structure between the small intestine and the large intestine in ruminants is

  1. Lumen

  2. Appendix

  3. Rumen

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

Rumen is a sac-like largest part of the stomach of the ruminants. It acts as a storage or holding vat for feed. It is also a fermentation vat.

So, the correct answer is 'Rumen'.

Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

The number of chambers in the stomach of ruminants is

  1. 3

  2. 2

  3. 4

  4. 1
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Ruminants have 4 chambers of stomach which include:-
1) Rumen - sac-like pouch acts as a storage or holding vat for feed.
2) Reticulum - honeycomb shaped contain heavy or dense feed of the animal.
3) Omasum - globe-shaped structure, absorb water and other substance from digestive contents.
4) Abomasum- only component lined with glands that release digestive enzyme and hydrochloric acid.
Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

Why cannot ruminants chew food at the same time they take in?

  1. Grass does not taste good.

  2. Grass contains cellulose that cannot be digested easily.

  3. The grass is hard in structure.

  4. Ruminants eat a lot of grass at the same time.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Ruminants are the herbivores and eat grasses. Grasses contains cellulase as their stored food. Cellulose needs an enzyme called cellulase for its digestion which is present in the rumen. Ruminants do not chew their food at the same time they take in as they require the fermented cud to be regurgitated and chewed. 
So the correct answer is 'Grass contains cellulose that cannot be digested easily'.
Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

The part of the stomach where a ruminant stores food is called as

  1. Lumen

  2. Rumen

  3. Tubule

  4. Artery
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Rumen is a sac-like structure. It is the largest part of the stomach of ruminants. It is a part where food is stored, mechanically processed and exposed to bacteria that synthesize cellulase enzyme to break cellulose.
So, the correct answer is 'Rumen'.
Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

The primary features of differentiation between ruminants and non-ruminants are the presence of which of the structure in ruminants?

  1. 5 chambered stomach

  2. 4 chambered stomach

  3. 3 chambered stomach

  4. 1 chambered stomach
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Ruminants have 4-chambered stomach. The four chambers are namely rumen, reticulum, omasum and abomasum. Like other vertebrates, ruminants (including deer and cattle), are unable to digest plant material directly, because they have 4-chambered stomach for better digestion.
So the correct answer is '4-chambered stomach'.
Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

The true stomach in cows is called as

  1. Rumen

  2. Abomasum

  3. Lumen

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
True stomach in cow is called abomasum. It is the only part of the ruminant's stomach that has glands, secreting acids and enzymes for digestion. It receives and digests food from omasum and pass it on to the small intestine.
So, the correct answer is 'Abomasum'.
Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

Humans cannot digest cellulose like cattle do because

  1. They have a smaller stomach.

  2. They do not have cellulose-digesting bacteria in their stomach.

  3. They do not consume cellulose.

  4. They have less digesting capacity than ruminants.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Food is stored in the plants as cellulose. Cellulase is an enzyme synthesized by bacteria in stomach of ruminant which is used to digest cellulose. Humans do not have cellulase and hence they cannot digest cellulose.
So, the correct answer is 'They do not have cellulose-digesting bacteria on their stomach'.
Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

The cud is brought back to the mouth during digestion in ruminants. This is called as

  1. Ingestion

  2. Regurgitation

  3. Egestion

  4. Absorption
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Ruminants have 4-chambered stomach. Reticulum is a part of ruminant's stomach that allow the animal to regurgitate the cud, to reprocess particulate matter and chew the cud again.
So the correct answer is 'Regurgitation'.
Multiple choice biology what do animals eat? digestion in ruminants nutrition in other organisms busy at work - our internal organs

The digestive system of cows is made up of

  1. Oesophagus

  2. Small and large intestine

  3. 4 chambered stomach

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The digestive system of cow is made up of oesophagus, 4-chambered stomach and small and large intestine. The food is passed through oesophagus from mouth to the stomach. The cow has 4-chambered stomach that digest and process the food and then pass it on the small and large intestine for absorption.
So the correct answer is 'All of the above'.
Multiple choice zoology diseases and immunity body defense system drug-target interaction pharmaceutical products and drug action

Stomach clears out pathogen by

  1. Secreting HCl

  2. Secreting digestive enzymes

  3. Both A and B

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

Hydrochloric acid (HCl) is secreted by the parietal cells of the stomach. It is highly acidic (pH 1.5 to 2) in nature and almost all the pathogens which enter the stomach through the ingested food are killed at this pH. The digestive enzyme pepsin released by the stomach can digest proteins but cannot actually kill the pathogens. Hence, the correct answer is 'HCl'.

Multiple choice zoology diseases and immunity body defense system drug-target interaction pharmaceutical products and drug action

Gastric secretions are under the control of 

  1. Cerebrum

  2. Hypothalamus

  3. Thalamus

  4. Medulla oblongata
Reveal answer Fill a bubble to check yourself
A,B,D Correct answer
Explanation

Gastric secretion starts with the stomach responds to the mere sight, smell, taste, or thought of food which process starts in the cerebrum. These sensory and mental inputs converge on the hypothalamus, which relays signals to the medulla oblongata. Vagus nerve fibres from the medulla stimulate the parasympathetic nervous system of the stomach which, in turn, stimulates gastric secretion.

So the answers are Cerebrum, Hypothalamus, and Medulla oblongata.

Multiple choice biology food production food production and microorganisms microbial products - food, medicines and industrial products uses of microorganisms

Cellulose present in the food of grazing animals is

  1. Digested by intestinal bacteria

  2. Digested by animal itself

  3. Digested partly by the animal and party by bacteria

  4. Passed out undigested
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Grazing is a method of feeding in which an animal feeds on plants such as grasses. The animals are called grazing animals. They are also called as Ruminants. Examples include cattle, sheep, goats, deer. They are capable of digesting cellulose present in the plants. The cellulose is digested by intestinal bacteria present in them. These bacteria possess the necessary enzymes to digest cellulose in the GI tract.

Thus, the correct answer is 'Digested by intestinal bacteria.'