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

What is the role of acid in our stomach?

  1. Acidify the food for proper action of pepsin

  2. Conversion of pepsinogen and prorenin into active forms of pepsin and renin

  3. Killing of microorganisms present in food

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The gastric juice is made up of hydrochloric acid, pepsinogen and other digestive enzymes, gastrin, mucus, and bicarbonates. It has a pH ranging from 1 to 2. Its low pH is essential in activating digestive enzyme such as pepsinogen and convert it into the active pepsin, a Proteolytic activity of pepsin and in destroying various pathogens. 

Thus, the correct answer is option D.

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

Gastric digestion takes place efficiently in

  1. Acidic medium

  2. Alkaline medium

  3. Neutral medium

  4. Highly alkaline medium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The gastric juice is made up of hydrochloric acid, pepsinogen and other digestive enzymes, gastrin, mucus, and bicarbonates. It has a pH ranging from 1 to 2. Its low pH is essential in activating many digestive enzymes and in destroying various pathogens. So, gastric digestion takes place efficiently in acidic medium
So, the correct answer is 'Acidic medium'
Multiple choice bio-chemistry coordination in life processes digestive system - organs process of digestion coordination in the process of digestion

The original function of the vertebrate stomach was

  1. Storage

  2. Digestion

  3. Enzyme secretion

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

According to the body's needs, the stomach decides what to do with the food. If the small intestine is full and busy absorbing molecules from a previous meal, for instance, the stomach temporarily stores the food. On the other hand, if the body is in need of nutrients and the small intestine is ready for absorption, the stomach begins to break down the macromolecules found in the food and creates a semi-liquid mixture called chyme. This decision-making step of the stomach helps control the pace of the digestive system. The stomach of vertebrates is able to break down macromolecules due to its highly acidic environment, which causes molecular bond stress and forces them to break. So, the original function of the vertebrate stomach was storage but, due to acidic medium it also breaks down the food. Thus, option A is correct.

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

The food passes through

  1. Mouth

  2. Oesophagus

  3. Both A and B

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

During digestion process fist food is ingested by mouth where chewing churning and mixing of food take place and make semi solid paste of food called as a bolus. Bolus then enters into the oesophagus where food moves through peristaltic movement and enters into the stomach. Thus, the correct answer is option C.

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

The internal secretion of ............ helps in digestion.

  1. Citric acid

  2. Sulphuric acid

  3. Acetic acid

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

The stomach wall secretes gastric juices and a mixture of HCl, pepsinogen and mucous. HCl increases the pH of the stomach due to which pepsinogen gets activated and gets converted into the active form pepsin which digests the protein molecule. Thus, the correct answer is option D. 

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

How is shape of stomach?

  1. As V

  2. As J

  3. As O

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

The stomach is a J-shaped, hollow organ located just inferior to the diaphragm in the left part of the abdominal cavity. It is located between the oesophagus and connects with the duodenum. It has two parts fundus and pyloric. 

Therefore, the correct answer is option B.

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

The gastric mill is the part of the stomach that is used for

  1. Storage

  2. Digestion

  3. Excretion

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

    The gizzard also referred to as the ventriculus, gastric mill, and gigerium is an organ found in the digestive tract of some animals, including crocodiles, alligators, dinosaurs, birds, earthworms, some fish, and some crustaceans.  This specialized stomach is constructed of thick muscular walls used for grinding up food. In certain insects and molluscs, the gizzard features chitinous plates or teeth. Hence, the gastric mill is the part of the stomach that is used for grinding.

    So, the correct answer is 'grinding'.

     

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

    Lowest pH is found in

    1. Small intestine

    2. Large intestine

    3. Stomach

    4. Esophagus

    5. Mouth
    Reveal answer Fill a bubble to check yourself
    C Correct answer
    Explanation

    The gastric glands of stomach produce gastric juice, which contains pepsinogen, HCl, and mucus. HCl imparts highly acidic pH to stomach which in turn supports conversion of inactive pepsinogen into active pepsin. The proper acidic environment of stomach triggers the opening of one way pyrrolic sphincter which in turn allow the chyme to move into the small intestine for further digestive processes. Thus, the correct answer is option C.

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

    The lining of the stomach is protected by

    1. Hydrochloric acid

    2. Mucous

    3. Digestive juicies

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

    Parietal cells in the mucosa are found in the inner lining of the stomach which secrete hydrochloric acid (HCl) into the stomach lumen, or cavity. It decreases the pH of the stomach and has corrosive nature hence can harm the stomach wall. The gastric juice consists mucous also. It gets deposits on the inner wall of the stomach to protect it from the corrosiveness of HCl.

    Therefore, the correct answer is option B.

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

    In Man the zymogen or chief cells are mainly found in ______________.

    1. Cardiac part of stomach

    2. Pyloric part of stomach

    3. Duodenum

    4. Fundic part of stomach
    Reveal answer Fill a bubble to check yourself
    D Correct answer
    Explanation

    Zymogen or chief cells are responsible for secreting pepsinogen and are primarily located in the gastric glands of the fundic region of the stomach.

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

    The wall of the stomach is protected against the action of HCl by ______________.

    1. Epidermal layer

    2. Mesodermal layer

    3. Mucous layer

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

    The stomach lining is protected from the highly acidic gastric juice (HCl) by a thick, alkaline mucous layer secreted by goblet cells.

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

    Proteolytic enzymes do not corrode lining of alimentary canal is

    1. They are secreted in inactive form

    2. Lining layer of alimentary canal does not contain protein

    3. The enzymes are not capable of digesting fat

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

    Proteolytic enzymes like pepsin are secreted as inactive zymogens (pepsinogen) to prevent them from digesting the proteins that make up the stomach wall itself.

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

    What will happen if secretion of parietal cells of gastric glands is blocked?

    1. Gastric juice is deficient of pepsinogen

    2. Gastric juice is deficient of chymosin

    3. Deficiency of HCl leads to nonconversion of inactive pepsinogen into active pepsin

    4. Nonrelease of enterokinase from duodenal mucosa and non-conversion of trypsinogen into trypsin
    Reveal answer Fill a bubble to check yourself
    C Correct answer
    Explanation

    Gastric glands are numerous microscopic tubular glands formed by the epithelium of stomach. The parietal cells (oxyntic cells) are large and most numerous on the sidewalls of gastric glands. They secrete hydrochloric acid and castle intrinsic factor. The peptic cells (zymogen) cells of gastric glands secrete gastric digestive enzymes as proenzymes-pepsinogen and prorennin and a small amount of gastric amylase and gastric lipase. The hydrochloric acid maintains a strongly acidic pH of about 1.5 to 2.5 in the stomach. HCl converts pepsinogen and prorennin to pepsin and rennin respectively. 

    So, the correct answer is 'Deficiency of HCl leads to nonconversion of inactive pepsinogen into active pepsin'.