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 digestive system - organs process of digestion coordination in the process of digestion

Digestion of food in human starts from

  1. Duodenum

  2. Small intestine

  3. Mouth

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

Digestion of food starts in mouth. It is carried out in following two ways

  • Mechanical digestion which is breaking of food into smaller chunks with the help of teeth and aided by muscular tongue.
  • Chemical digestion due to ptyalin (salivary amylase) in saliva
  • So, the correct answer is 'Mouth'

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

The structure which prevents the entry of food into respiratory tract is

  1. Pharynx

  2. Larynx

  3. Glottis

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

The epiglottis is a flexible flap at the superior end of the larynx in the throat. It acts as a switch between the larynx and the esophagus to permit air to enter the airway to the lungs and food to pass into the gastrointestinal tract. The epiglottis also protects the body from choking on food that would normally obstruct the airway.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

Digestion of food in human starts from which part of alimentary canal?

  1. Buccal cavity

  2. Small intestine

  3. Duodenum

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

Carbohydrate digestion begins in the mouth or buccal cavity. The salivary glands in the mouth secrete saliva, which helps to moisten the food. The food is then chewed while the salivary glands also release the enzyme salivary amylase, which begins the process of breaking down the polysaccharides in the carbohydrate food.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

A bolus is

  1. A mass of crushed food moistened with saliva

  2. The semisolid material resulting from partial digestion in the stomach

  3. The milky emulsified fatabsorbed from small intestine

  4. Indigestible materials that helps in movement and absorption
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A bolus is a mass of food that (with animals that can chew) has been chewed at the point of swallowing. Under normal circumstances, the bolus then travels down the oesophagus to the stomach for digestion. Bolus has the same colour as the food that has been chewed by the person and is different from chyme. The bolus is a rolled up ball-like structure formed when the animal is about to swallow. Its pH is alkaline because of the presence of saliva. Thus, option A is correct.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

Where does the process of food digestion start in human being?

  1. Stomach

  2. Food canal

  3. Mouth

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

Digestion of food starts in the mouth in humans. In the mouth masticated food gets mixed with saliva secreted by salivary gland. Saliva is a mixture of water, electrolytes, ptyalin enzyme (salivary amylase). The digestion of starch is initiated in the mouth due to the action of salivary amylase. Enzymatic hydrolysis helps in the partial breakdown of starch into maltose, isomaltose.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

Ingestion of food  in human beings is facilited by

  1. Oesophagus

  2. Buccal activity

  3. Muscular tongue

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

The food is ingested through the mouth. The mouth contains tongue, teeth and salivary glands. Teeth break the food into smaller particles. This process is called as mastication. The chewed food is mixed with saliva. Saliva is a watery fluid secreted by the salivary glands. Saliva contains a type of enzyme called the salivary amylase, which converts starch into sugar. The tongue is a muscular organ. Tongue helps to mix saliva in the food. It also helps to push the food down the food-pipe or oesophagus. Taste receptors are present in tongue and give us the sense of taste. 

Therefore, the correct answer is option C.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

Digestion begins in the mouth. Which of the following statement is incorrect?

  1. The tongue aids in the digestion of the food.

  2. The saliva changes some of the starches in the food to sugar.

  3. The tongue keeps the food in place in the mouth while the food is being chewed.

  4. The digestive juices can react more easily with food when chewed.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The tongue consists of eight interwoven, striated muscles that can move in any direction, making it quite flexible. Throughout the muscles are glands and fat, while the outside is covered by a mucus membrane. The top of the tongue, also called as the dorsum, is covered with papillae, tiny nodes that contain the taste buds and the serous glands.
Produced in salivary glands, saliva is 98% water, but it contains many important substances, including electrolytes, mucus, antibacterial compounds and various enzymes. The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily.
Therefore, the correct answer is option A.
Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

The first stage of digestion in human beings takes place in

  1. Oesophagus

  2. Small intenstine

  3. Buccal cavity

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

The fist stage of digestion in human being takes place in the buccal cavity where the chewing and churning of food and mixing of saliva occurs. Saliva consists salivary amylase which acts on the starch molecule of food and converts it into the simple form. The semisolid food with saliva in buccal cavity is called as a bolus. Bolus is then transferred to the stomach with the help of peristaltic movement of the oesophagus. Thus, the correct answer is option C.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

In man even though both air and food go through the pharynx, food does not normally enter the wind pipe because during swallowing of food

  1. The epiglottis covers the glottis

  2. Sphincter of Oddi closes the hepato-pancreatic duct

  3. Pyloric sphincter covers the opening of stomach into the duodenum

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

During swallowing, the epiglottis acts as a flap that closes over the glottis (the opening to the trachea) to prevent food from entering the windpipe.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

A complete digestive tract consists of an oral and an anal opening.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In humans, the alimentary canal begins with an anterior opening, called mouth and it opens out posteriorly through another opening, anus. Such an alimentary canal is called complete. In some animals like coelenterates only single opening is present, such an alimentary canal is called incomplete. 

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

In humans, protein digestion is completed in the mouth.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. The pancreas produces a juice containing several enzymes that break down carbohydrates, fats, and proteins in food. Hence, partial digestion occurs in the mouth.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

Digestion of starch starts from

  1. Stomach

  2. Intestine

  3. Oesophagus

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

Carbohydrate digestion begins in the mouth or buccal cavity. The salivary glands in the mouth secrete saliva, which helps to moisten the food. The food is then chewed while the salivary glands also release the enzyme salivary amylase, which begins the process of breaking down the carbohydrate food.

Multiple choice bio-chemistry digestion digestive system - organs process of digestion coordination in the process of digestion

Chewing is an example of

  1. Chemical digestion

  2. Mechanical digestion

  3. Involuntary action

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

There are two kinds of digestion: mechanical and chemical. In mechanical digestion, food particles are physically broken down into smaller pieces. It begins in the mouth where the food is chewed. 

Therefore, the correct answer is option B.

Multiple choice bio-chemistry digestion digestive glands liver pancreas

The enzyme that is not present in succus entericus is

  1. Maltase

  2. Nucleases

  3. Nucleosidase

  4. Lipase
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Succus entericus contain enzymes like disaccharidases (maltase, lactase, sucrase, invertase), dipeptidases, lipases, nucleosidases. Nucleases is found in the pancreatic juice.
  • So the correct option is 'B'