Digestion and Absorption


What is pancreas? Mention the major secretions of pancreas that are helpful in digestion.


Pancreas is a heterocrine (both exocrine and endocrine) gland situated between the limbs of the ‘U’ shaped duodenum. The exocrine part of pancreas secrete pancreatic juice which contains three proenzymes; trypsinogen, chymotrypsinogen and procarboxypeptidase and some enzymes; DNase, RNase, pancreatic amylase and lipase. Pancreatic juice helps in digestion of starch, proteins, fats and nucleic acids. Endocrine part of pancreas consists of islets of Langerhans which contains a-and P-cells which secrete hormone glucagon and insulin respectively, which regulate blood glucose level.
Proteins, proteoses and peptones present in the chyme, on reaching the intestine are acted upon by the proteolytic enzymes of pancreatic juice as given below:
Carbohydrates, fats and nucleic acids present in the food are also hydrolysed by pancreatic juice.


Digestion and Absorption

Q 1.

Correct the statement given below by the right option shown in the bracket against them.  Absorption of amino acids and glycerol takes place in the (small intestine/ large intestine).  The faeces in the rectum initiate a reflex causing an urge for its removal (neural / hormonal).  Skin and eyes turn yellow in infection, (liver/stomach).  Rennin is a proteolytic enzyme found in gastric juice of (infants / adults).  Pancreatic juice and bHe are released through (intestine-pancreatic/hepato ¬pancreatic duct).  Oipeptides, disaccharides and glycerides are broken down into simple substances in region of small intestine (jejunum/duodenum).

Q 2.

Explain the term the codont and diphyodont.

Q 3.

Discuss the role of hepato – pancreatic complex in digestion of carbohydrate, protein and fat components of food.

Q 4.

The food mixes thoroughly with the acidic gastric juice of the stomach by the churning movements of its muscular wall. What do we call the food then?

Q 5.

What are three major types of cells found in the gastric glands? Name their secretions.

Q 6.

What do we call the type of teeth attachment to jaw bones in which each tooth is embedded in a socket of jaw bones?

Q 7.

Stomach is located in upper left portion of the abdominal cavity and has three major parts. Name these three parts.

Q 8.

Does gall bladder make bile?

Q 9.

Give the dental formula of human beings.

Q 10.

Match the enzymes with their respective substrates and choose the right one among options given.
Column-I                                                     Column-II
A.Lipase                                                      (i)Dipeptides
B.Nuclease                                                 (ii)Fats
C.Carboxypeptidase                                (iii)Nucleic acids
D.Dipeptidases                                         (iv)Proteins,peptones and proteoses
(a) A-(ii), B-(iii), C-(i), D-(iv)
(b) A-(iii), B-(iv), C-(ii), D-(i)
(c) A-(iii), B-(i), C-{iv), D-(ii)
(d) A-(ii), B-(iii), C-(iv), D-(i)

Q 11.

Define digestion in one sentence.

Q 12.

What is the role of gall bladder? What may happen if it stops functioning or is removed?

Q 13.

Answer briefly:
(a) Why are villi present in the intestine and not in the stomach?
(b) How does pepsinogen change into its active form ?
(c) What are the basic layers of the wall of alimentary canal?
(d) How does bile help in the digestion of fats ?

Q 14.

In which part of alimentary canal does absorption of water, simple sugars and alcohol takes place?

Q 15.

Choose the correct answer among the following:
(a) Gastric juice contains
(i) pepsin, lipase and rennin
(ii) trypsin, lipase and rennin
(iii) trypsin, pepsin and lipase
(iv) trypsin, pepsin and rennin.
(b) Succus entericus is the name given to
(i) a junction between ileum and large intestine
(ii) intestinal juice
(iii) swelling in the gut
(iv) appendix.

Q 16.

Try psinogen is an inactive enzyme of pancreatic juice. An enzyme, enterokinase, activates it. Which tissue/ cells secrete this enzyme?/ How is it activated?

Q 17.

What are the functions of liver?

Q 18.

How are the activities of gastro-intestinal tract regulated?

Q 19.

Describe the digestive role of chymotrypsin. Which two other digestive enzymes of the same category are secreted by its source gland ?

Q 20.

Name different types of teeth and their number in an adult human.

Q 21.

Name the part of the alimentary canal where major absorption of digested food takes place. What are the absorbed forms of different kinds of food materials?

Q 22.

What would happen if HCl were not secreted in the stomach ?

Q 23.

Match the two columns and select the right one among options given.
Column-I                                           Column-ll
A.Duodenum                                   (i) A cartilaginous flap
B.Epiglottis                                      (ii)Small blind sac
C.Glottis                                           (iii)’U’shaped structure emerging from the stomach
D. Caecum                                        (iv)Opening of wind pipe
(a) A-(i), B-(ii), C-(iii), D-(iv)
(b) A-(iv), B-(iii), C-(ii), D-(i)
(c) A-(iii), B-(i), C-(iv), D-(ii)
(d) A-(ii), B-(iv), C-(i), D-(iii)

Q 24.

Name the enzymes involved in the breakdown of nucleotides into sugars and bases.

Q 25.

Discuss mechanisms of absorption.

Q 26.

Match column I with column II.
Column I                         Column II
(a) Bilirubin and           (i)Parotid biliverdin
(b) Hydrolysis of          (ii)Bile starch
(c) Digestion of fat       (iii)Lipases
(d) Salivary gland        (iv) Amylases

Q 27.

How are polysaccharides and disaccharides digested ?

Q 28.

State the role of pancreatic juice in digestion of proteins.

Q 29.

A person had roti and dal for his lunch.Trace the changes in those during its passage through the alimentary canal.

Q 30.

What is pancreas? Mention the major secretions of pancreas that are helpful in digestion.

Q 31.

Explain the process of digestion in the buccal cavity with a note on the arrangement of teeth.

Q 32.

How is the intestinal mucosa protected from the acidic food entering from stomach?

Q 33.

Bile juice contains no digestive enzymes, yet it is important for digestion. Why ?

Q 34.

Correct the following statements by deleting  one of entries (given in italics).
(a) Goblet cells are located in the intestinal mucosal epithelium and secrete chymotrypsin / mucus.
(b) Fats are broken down into di-and monoglycerides with the help of amylase/ lipases.
(c) Gastric glands of stomach mucosa have oxynticcell/chief cells which secrete HCl.
(d) Saliva contains enzymes that digest starch /protein.

Q 35.

Describe the process of digestion of protein in stomach.

Q 36.

How does butter in your food get digested and absorbed in the body ?

Q 37.

What are the various enzymatic types of glandular secretions in our gut helping digestion of food? What is the nature of end products obtained after complete digestion of food?

Q 38.

Describe the enzymatic action on fats in the duodenum.

Q 39.

Distinguish between constipation and indigestion. Mention their major causes.

Q 40.

List the organs of human alimentary canal and name the major digestive glands with their location.

Q 41.

Discuss the main steps in the digestion of proteins as the food passes through different parts of the alimentary canal.

Q 42.

Describe the process of digestion of protein in stomach.