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Q1. Which of the following is the largest gland in an adult man? 

• 1) Thyroid
• 2) Thymus
• 3) Liver
• 4) Pancreas

Solution

The liver is the largest glandular organ in the body and performs many vital functions to keep the body pure of toxins and harmful substances. It is a vital organ which supports nearly every organ in the body in some way. Without a healthy liver, a person cannot survive. An average adult liver weighs about three pounds.

Q2. Bile contribution to digestion is   

• 1) Emulsification of dietary fats  
• 2) Phagocytosis  
• 3) Carbohydrate digestion  
• 4) Nucleic acid meta bolism  

Solution

The liver secretes bile which is stored in the gall bladder. Bile salts help in the digestion of fats in the small intestine which converts large fat droplets into small ones. This process is called emulsification.  

Q3. ‘Crypts of Lieberkühn’ are found in

• 1) Gall bladder
• 2) Intestine
• 3) Liver
• 4) Pancreas

Solution

The ‘Crypts of Lieberkühn’ (also known as the intestinal glands) are glands found in the walls of the small intestine. The crypts which are embedded within the epithelial lining secrete various enzymes, including sucrase and maltase.

Q4. The enzyme pepsin acts in  

• 1) Intestine  
• 2) Acidic medium in the pancreas  
• 3) Acidic medium in stomach  
• 4) Mouth  

Solution

Pepsin hydrolyses proteins into short polypeptides in an acidic medium of pH 2.0 in the stomach.  

Q5. Peptic cells secrete 

• 1) HCl
• 2) Cholecystokinin
• 3) Pepsin
• 4) Gastrin

Solution

Peptic cells of the gastric glands secrete digestive enzymes such as pepsin and lipase.

Q6. Name the enzyme secreted by the peptic cells.

Solution

Pepsinogen

Q7. State the role of lysozyme present in the saliva.

Solution

Lysozyme acts as an anti-bacterial agent and prevents infections.

Q8. The richest sources of Vitamin B12 are

• 1) Goat’s liver and Spirulina
• 2) Rice and hen’s egg
• 3) Chocolate and green gram
• 4) Carrot and chicken’s breast

Solution

Vitamin B12 is the only vitamin which is not found in vegetables. It is present in animal protein such as meat, liver, fish and Spirulina. It promotes DNA synthesis, maturation of RBCs and myelin formation.

Q9. Which one of the following is a matching pair of a substrate and its particular digestive enzyme?  

• 1) Casein - Chymotrypsin  
• 2) Maltose - Maltase  
• 3) Starch - Steapsin  
• 4) Lactose - Rennin  

Solution

Intestinal juices contain several oligosaccharides which hydrolyse specific polysaccharides into their monosaccharides. Maltase is one of them, which hydrolyses maltose into two glucose molecules.  

Q10. How many teeth appear twice during the lifespan of an individual?   

• 1) 16  
• 2) 20  
• 3) 32  
• 4) 22  

Solution

The teeth which appear twice during the lifespan are the milk teeth (8 incisors, 4 canines and 8 molars) which are temporary and erupt when the child is about 6 months old. They again appear by the end of 24 months.  

Q11. Kwashiorkor disease occurs due to deficiency of

• 1) Sugars
• 2) Hormones
• 3) Fats
• 4) Proteins

Solution

Kwashiorkor is caused by deficiency of protein in the diet.

Q12. Name the hormone which stimulates the secretion of gastric juice. 

• 1) Enterokinase
• 2) Gastrin
• 3) Enterogastrone
• 4) Renin

Solution

The hormone which stimulates the secretion of gastric juice is gastrin. It is secreted by the parietal cells of the stomach and aids in gastric motility.

Q13. Carbohydrate digestion first occurs in the

• 1) None of the above
• 2) Intestine
• 3) Mouth
• 4) Stomach

Solution

Carbohydrate digestion starts in the oral cavity, in which the food is mixed with saliva which then moves into the stomach.

Q14. Chief cells of the gastric glands are   

• 1) Simple tubular  
• 2) Compound tubular  
• 3) Branched tubular  
• 4) Coiled tubular  

Solution

Gastric glands are numerous microscopic, tubular glands formed by the epithelium of the stomach.  

Q15. Anxiety and eating spicy food together in an otherwise normal human may lead to 

• 1) Vomiting
• 2) Indigestion
• 3) Jaundice
• 4) Diarrhoea

Solution

Anxiety and eating spicy food together in an otherwise normal human may lead to indigestion.

Q16. Why are humans called heterodonts?

Solution

Human beings show the presence of four types of teeth, i.e. canines, incisors, molars and premolars. Hence, they are called heterodonts.

Q17. Explain the role of the buccal cavity during digestion.

Solution

The buccal cavity performs mastication of food and facilitates swallowing. The teeth and tongue mix the food thoroughly with saliva. The mucus present in the saliva helps in lubricating food, and it also adheres masticated food particles together into a bolus. The bolus is then swallowed and conveyed into the pharynx.

Q18. In man, the zymogen or chief cells are mainly found in

• 1) Duodenum
• 2) Fundic part of stomach
• 3) Pyloric part of stomach
• 4) Cardiac part of stomach

Solution

Chief cells or zymogen are mainly found in the fundic part of the stomach.

Q19. When breastfeeding is replaced by less nutritive food low in proteins and calories in infants below the age of one year, they are likely to suffer from  

• 1) Kwashiorkor  
• 2) Pellagra  
• 3) Marasmus  
• 4) Rickets  

Solution

Prolonged starvation causes marasmus due to a generalised wasting of body because of both energy and protein deficiency. The body becomes lean and weak, the eyes are depressed and the skin is wrinkled.  

Q20. Which of the following is a fat-soluble vitamin and its related deficiency disease?   

• 1) Calciferol - Pellagra  
• 2) Ascorbic acid - Scurvy  
• 3) Cobalamin - Beri-beri  
• 4) Retinol - Xerophthalmia  

Solution

Vitamin A (retinol) and Vitamin D (calciferol) are fat-soluble vitamins, but the deficiency of calciferol causes rickets and osteomalacia.     Xerophthalmia is caused by deficiency of Vitamin A.  

Q21. Digestive enzymes are 

• 1) Hydrolases
• 2) Transferases
• 3) Lyases
• 4) Oxidoreductases

Solution

Any enzyme which uses hydrolysis (breaking a molecule in two, resulting in two smaller molecules) is called a hydrolase. In chemical digestion, hydrolysis is the main chemical reaction used by the enzymes to break proteins, lipids, carbohydrates and other complex molecules into smaller pieces.

Q22. Which one of the following pairs is not correctly matched?  

• 1) Vitamin B2 - Pellagra  
• 2) Vitamin B1 - Beri-beri  
• 3) Vitamin B6 - Loss of appetite  
• 4) Vitamin B12 - Pernicious anaemia  

Solution

Vitamin B2 helps in RBC production. Its deficiency causes cheilosis.  

Q23. The crown of teeth is covered by 

• 1) Enamel
• 2) Dentine
• 3) None of the above
• 4) Both 1 and 2 above

Solution

Of the three regions of the teeth, the part which projects above the gums is the crown which is covered by enamel, the hardest substance of the human body.

Q24. Where do you find the sphincter of Oddi?

Solution

The sphincter of Oddi is situated between the opening of the hepatopancreatic duct and the duodenum.

Q25. Calcium deficiency occurs in the absence of vitamin

• 1) E
• 2) C
• 3) D
• 4) B

Solution

Vitamin D mainly helps in the Ca/P balance of body fluids. It increases absorption of calcium from the intestines, so it is necessary for formation of healthy bones and teeth. Deficiency of Vitamin D causes an increased loss of calcium ions in urine; thus, calcium ions get deposited in the bones. This causes rickets in children and osteomalacia in pregnant woman.

Q26. Name three secretions released into the small intestine.

Solution

Bile, pancreatic juice and intestinal juice

Q27. What is assimilation?

Solution

Assimilation is the use of absorbed food or nutrients by the tissues.

Q28. Secretin and cholecystokinin are digestive hormones. These are secreted by 

• 1) Duodenum
• 2) Oesophagus
• 3) Ileum
• 4) Pyloric stomach

Solution

Secretin and cholecystokinin are two main gastrointestinal hormones secreted in the duodenum of the alimentary canal. Cholecystokinin stimulates gall bladder contraction and thus increases the flow of bile salts into the intestine. Secretin stimulates the release of an alkaline pancreatic fluid which neutralises stomach acid as it enters the intestine.

Q29. Write any five reactions which occur in the duodenum.  

Solution

Q30. Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?   

• 1) Protease  
• 2) Lipase  
• 3) Exonuclease  
• 4) Endonuclease  

Solution

The groups of enzymes which catalyse the hydrolysis of phosphodiester bonds between nucleic acids in a polynucleotide chain are endonucleases.  

Q31. The pancreas produces  

• 1) Three digestive enzymes and one hormone  
• 2) Three digestive enzymes and two hormones  
• 3) Three digestive enzymes and no hormone  
• 4) Two digestive enzymes and one hormone  

Solution

The pancreas produces pancreatic juice which contains trypsinogen, chymotrypsin, carboxypeptidase, lipase, pancreatic alpha amylase, elastase and nucleases. Of these, the first three are concerned with protein digestion which converts proteins into small peptides.     Other than these, the pancreas also secretes the hormones insulin and glucagon which act antagonistically in controlling the blood sugar level.  

Q32. Write any two causes of indigestion.

Solution

Inadequate enzyme secretion and anxiety

Q33. Name the valve which prevents the backflow of the faeces into the large intestine.  

Solution

Ileocaecal valve  

Q34. For a person suffering from high blood cholesterol, the physicians recommend  

• 1) Pure ‘desi ghee’ or butter  
• 2) Vegetable oil such as groundnut oil  
• 3) Red meat with layers of fats  
• 4) Vanaspati margarine  

Solution

A high intake of saturated fat causes high blood cholesterol which ultimately gets deposited in the walls of the arteries causing their blockage resulting in various cardiac diseases. Ghee, butter, red meat and vanaspati are rich sources of saturated fats. A patient with high blood cholesterol is suggested to consume unsaturated fats as vegetable oils.  

Q35. Bile secretion is proportional to the concentration of 

• 1) Proteins
• 2) Carbohydrates
• 3) None of the above
• 4) Fats

Solution

The liver secretes bile which is stored in the gall bladder. Bile salts help in the digestion of fats in the small intestine which converts large fat droplets into small ones.

Q36. Name the capsule which covers the hepatic lobule.

Solution

Glisson’s capsule

Q37. Name the layer which forms the serosa.

Solution

Mesothelium

Q38. State the role of the large intestine.

Solution

Role of the large intestine: Water is absorbed in the large intestine, and drugs and minerals are also absorbed to some extent. The large intestine secretes mucus which helps in adhering undigested particles together and lubricates them for an easy passage outside the body.

Q39. Draw the diagrams of     Section of the small intestine   Arrangement of teeth human  

Solution

Section of the small intestine:         Arrangement of teeth human:      

Q40. Oxyntic cells secrete   

• 1) NaOH  
• 2) Trypsin  
• 3) HCl  
• 4) Pepsin  

Solution

Oxyntic cells (also called parietal cells) lie against the basement membrane and secrete hydrochloric acid.  

Q41. Name the point of attachment between the tongue and the oral cavity.  

Solution

Frenulum  

Q42. Name teeth found in an adult human.

Solution

Incisors, canines, molars and premolars.

Q43. Stool of a person contains whitish grey colour due to malfunction of which type of organ?  

• 1) Liver  
• 2) Spleen  
• 3) Pancreas  
• 4) Kidney  

Solution

Bilirubin is broken down to urobilinogen and stercobilinogen. The yellowish brown colour of stool is due to stercobilinogen. Due to the malfunctioning of liver, insufficient production of stercobilinogen leads to white stool.  

Q44. ‘Glisson’s capsule’ is associated with  

• 1) Lung  
• 2) Liver  
• 3) Kidney  
• 4) Pancreas  

Solution

‘Glisson’s capsule’ is the capsule of the liver. It is a layer of connective tissue surrounding the liver and enclosing the hepatic artery, portal vein and bile ducts within the liver.  

Q45. Where is the liver situated in the body? Name the structural and functional units of the liver.

Solution

The liver is situated in the abdominal cavity just below the diaphragm. Hepatic lobules are the structural and functional units of the liver.

Q46. The gastric juice contains 

• 1) Pepsin, Lipase, Rennin
• 2) Pepsin, Amylase, Trypsin
• 3) Trypsin, Pepsin, Rennin
• 4) Trypsin, Pepsin, Lipase

Solution

Gastric juice is secreted by gastric glands which also secrete digestive enzymes such as pepsin and rennin. The gastric glands also produce a small amount of gastric amylase and gastric lipase.

Q47. Argentaffin cells in human beings are found in   

• 1) Liver  
• 2) Small intestine  
• 3) Large intestine  
• 4) Stomach  

Solution

Argentaffin cells, the round or partly flattened cells, occur in the tissue lining the stomach and contain granules thought to have a secretory function.  

Q48. In humans, sphincter of Oddi is associated with the opening of  

• 1) Hepatopancreatic ampulla  
• 2) Pyloric stomach  
• 3) Common hepatic duct  
• 4) Oesophagus  

Solution

The sphincter of ampulla or sphincter of Oddi is a muscular valve which controls the flow of digestive juices (bile and pancreatic juice) through the hepatopancreatic ampulla into the second part of the duodenum.  

Q49. Name the lymph vessel which joins villi.  

Solution

Lacteal vessel  

Q50. What will happen if the secretion of the parietal cells of the gastric glands is blocked within an inhibitor?  

• 1) Gastric juice will lack pepsinogen.  
• 2) In the absence of HCl secretion, inactive pepsinogen is not converted into active enzyme pepsin.  
• 3) Gastric juice will lack chymosin.  
• 4) Enterokinase will not be released from duodenal mucosa, so trypsinogen is not converted to trypsin.  

Solution

Gastric glands are numerous microscopic tubular glands formed by the epithelium of the stomach. The parietal cells are large and most numerous on the side walls of gastric glands. They secrete hydrochloric acid and Castle’s intrinsic factor. The peptic 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.  

Q51. Pepsinogen is secreted by   

• 1) Chief cell  
• 2) Parietal cell  
• 3) Mast cell  
• 4) Oxyntic cell  

Solution

Pepsinogen and prorennin are gastric digestive enzymes secreted by the chief cells or peptic cells of the gastric glands.  

Q52. Name the enzyme which gets activated due to enterokinase.

Solution

Trypsinogen

Q53. Pellagra is caused by the deficiency of

• 1) Pyridoxine
• 2) Folic acid
• 3) Niacin
• 4) Biotin

Solution

A disease called pellagra is caused by deficiency of Vitamin B3.

Q54. Name various substances present in bile. State the functions of bile.

Solution

Various substances present in bile are bilirubin, biliverdin, bile salts, cholesterol and phospholipids. Bile helps in breaking down of the fats into small micelles, and this process is called emulsification. Bile also helps in activation of lipases.

Q55. What is ?  

Solution

The dental formula of humans.  

Q56. Name the cells which secrete HCl in the stomach.

Solution

Oxyntic cells

Q57. Study the given reaction and identify A.    

Solution

Q58. State the optimum pH required for the action of salivary amylase on carbohydrates.

Solution

The optimum pH for the action of salivary amylase on carbohydrates is 6.8.

Q59. State the action of the following enzymes and the resulting end-product: Carboxypeptidase Sucrase Nucleosidases Amylase

Solution

Carboxypeptidase - It acts on proteins, peptones and proteoses. The end-product is dipeptides. Sucrase - Sucrase acts on sucrose, and the end-products are glucose and fructose. Nucleosidases - These enzymes act on nucleosides, and the end-products are sugars and nitrogen bases. Amylase - It acts on starch, and the end-product is disaccharides.

Q60. Bile salts act as an activator of which enzyme?   

• 1) Pancreatic lipase  
• 2) Trypsinogen  
• 3) Pepsinogen  
• 4) Lipase  

Solution

Bile contains no enzyme, but it activates the enzyme lipase.  

Q61. Vitamin K is required for

• 1) Change of prothrombin to thrombin
• 2) Synthesis of prothrombin
• 3) Change of fibrinogen to fibrin
• 4) Formation of thromboplastin

Solution

Vitamin K is essential for the formation of prothrombin from liver cells and helps in blood coagulation. Vitamin K is also known as antihaemorrhagic factor or phylloquinone.

Q62. What is the optimal pH for pepsin in the stomach?

Solution

1.8 is the optimal pH for pepsins.

Q63. Given is the transverse section of the gut. Study the section and label A, B, C and D.  

Solution

A - Sub-mucosa B - Inner circular muscularis C - Outer longitudinal muscularis D - Serosa

Q64. State the term used for the protein-coated fat droplets.

Solution

Chylomicrons

Q65. Name the region of the large intestine where symbiotic microorganisms take their shelter.

Solution

Caecum

Q66. Why are humans called thecodonts?

Solution

In humans, teeth are embedded in the sockets of the jaw bone, and such type of attachment is called thecodont. Hence, humans are called thecodonts.

Q67. Name the ions present in the saliva.  

Solution

The ions present in saliva are Na⁺, K⁺, Cl⁻ and HCO₃⁻.  

Q68. Name the bile pigments present in bile.

Solution

Bilirubin and biliverdin

Q69. What kinds of muscles are present in the muscularis layer of the alimentary canal?

Solution

Smooth muscles

Q70. What is the technical term for swallowing food?

Solution

Deglutition

Q71. What are partially hydrolysed proteins called?

Solution

Peptones

Q72. Name the movements which help to pass the food down through the oesophagus.

Solution

Peristalsis

Q73. Name the enzyme which digests milk proteins in infants.

Solution

Rennin

Q74. Name the two ducts which form the bile duct.

Solution

The cystic duct and the hepatic duct join to form the common bile duct.

Q75. Name the three types of cells present in the gastric glands of the stomach, and also state their secretions. Also state the significance of the secretions.  

Solution

The three types of cells found in gastric glands and their secretions are     Mucus neck cells secrete mucus. Mucus provides lubrication and protection to the mucosal epithelium from the excoriating effect of HCl.   Peptic or chief cells secrete pepsinogen. Pepsinogen converts proteins into proteoses which are further converted into peptones.   Oxyntic cells or parietal cells which secrete HCl and intrinsic factors. HCl provides acidic pH 1.8 which is necessary for the action of pepsins. Intrinsic factors are required for the absorption of vitamin B₁₂.

Q76. Explain diphyodont dentition.

Solution

Dentition in which animals exhibit two kinds of teeth in their life - first deciduous teeth and second adult teeth - is called diphyodont dentition.

Q77. What is diarrhoea? Why do skin and eyes turn yellow in jaundice?

Solution

Diarrhoea is the abnormal frequency of bowel movement which increases the liquidity of the faecal discharge. In jaundice, due to the deposition of bile, the skin and eyes turn yellow.

Q78. State the four layers of the walls of the alimentary canal.  

Solution

The four layers of the walls of the alimentary canal are     Outermost serosa made of mesothelium.   Middle muscularis formed of smooth muscles arranged in inner circular and outer longitudinal layers.   The inner mucosal layer formed of the loose connective tissue containing nerves, blood vessels and lymph vessels.   The innermost layer is the sub-mucosal layer which lines the lumen and consists of rugae and villi.  

Q79. Name the gland present in the lower jaw.

Solution

Sub-maxillary gland

Q80. Name the enzymes present in the saliva.

Solution

Salivary amylase and lysozyme

Q81. In which region of the small intestine are the simple substances absorbed in blood?

Solution

Jejunum and ileum

Q82. Where are the pyloric sphincters present?

Solution

Pyloric sphincters are present between the stomach and the small intestine.

Q83. Draw an outline of the human digestive system. Label any ten parts.

Solution

Human digestive system:   (Label any ten parts)

Q84. State the common name given to the secretions of the intestinal mucosa and the secretions of the goblets cells.

Solution

Succus entericus

Q85. What is the technical term used for temporary milk teeth?

Solution

Deciduous teeth

Q86. Name the duct which releases bile and pancreatic juice. Where are these juices released? Name the inactive enzymes present in the pancreatic juices.  

Solution

The hepatopancreatic duct releases bile and pancreatic juice. These juices are released into the small intestine. The enzymes present in the pancreatic juices are trypsinogen, chymotrypsinogen, procarboxypeptidases, amylases, lipases, nucleases etc.  

Q87. What is the function of the gastro-oesophageal sphincter?  

Solution

The gastro-oesophageal sphincter regulates the opening of the oesophagus into the stomach.