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?
ln the buccal cavity, saliva secreted by the salivary glands contains salivary amylase that acts as follows:
Gastric juice of the stomach contains proenzyme pepsinogen, which on exposure to hydrochloric acid gets converted into active enzyme, pepsin. Pepsin is a proteolytic enzyme that converts proteins into proteoses and peptones. Rennin is a proteolytic enzyme found in the gastric juice of infants which helps in the digestion of milk proteins. Small amounts of lipases are also secreted by gastric glands.
Bile, pancreatic juice and intestinal juice (succus erttericus) are the secretions released into the small intestine. Pancreatic juice and bile are released through hepato-pancreatic duct into duodenum. Pancreas secretes pancreatic juice that contains inactive enzymes like trypsinogen, chymotrypsinogen, procarboxypeptidases and enzymes like amylases, lipases and nuclease. An enzyme, enterokinase, secreted by the intestinal mucosa converts trypsinogen into active trypsin, which in turn activates the other enzymes in the pancreatic juice. The food reaching the small intestine is acted upon by the enzymes of pancreatic juice as follows:
Bile secreted by liver does not contain any enzyme. It only helps in emulsification of fats and activation of lipases.
In the duodenum of the small intestine, the enzymes of the succus entericus act on the end products of the above reactions to form the respective simple absorbable form.
The end products of the carbohydrate digestion are glucose, protein digestion are amino acids, fat digestion are fatty acids and glycerol and nucleic acid digestion are sugars and bases.
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).
Discuss the role of hepato – pancreatic complex in digestion of carbohydrate, protein and fat components of food.
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?
What do we call the type of teeth attachment to jaw bones in which each tooth is embedded in a socket of jaw bones?
Stomach is located in upper left portion of the abdominal cavity and has three major parts. Name these three parts.
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)
What is the role of gall bladder? What may happen if it stops functioning or is removed?
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 ?
In which part of alimentary canal does absorption of water, simple sugars and alcohol takes place?
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.
Try psinogen is an inactive enzyme of pancreatic juice. An enzyme, enterokinase, activates it. Which tissue/ cells secrete this enzyme?/ How is it activated?
Describe the digestive role of chymotrypsin. Which two other digestive enzymes of the same category are secreted by its source gland ?
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?
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)
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
A person had roti and dal for his lunch.Trace the changes in those during its passage through the alimentary canal.
What is pancreas? Mention the major secretions of pancreas that are helpful in digestion.
Explain the process of digestion in the buccal cavity with a note on the arrangement of teeth.
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.
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?
List the organs of human alimentary canal and name the major digestive glands with their location.
Discuss the main steps in the digestion of proteins as the food passes through different parts of the alimentary canal.