Identify the correct set of statements regarding villi and mucosal modifications in the small intestine:
I. Villi are small finger-like foldings formed by the mucosa of the small intestine. II. The cells lining the villi produce microscopic projections called microvilli, giving a brush border appearance. III. Villi are supplied with a network of capillaries and a large lymph vessel called the lacteal. IV. Mucosal epithelium has goblet cells which secrete mucus that helps in lubrication.
Explanation: All statements are correct. Villi are finger-like projections of the mucosa that increase the absorptive surface area. The epithelial cells possess microvilli forming the brush border. Each villus contains blood capillaries and a lymph vessel called the lacteal. Goblet cells secrete mucus for lubrication and protection.
Question 22 of 100
📘 CLASS XI
Read the following statements about the digestion and absorption sites and select the correct option:
I. The breakdown of biomacromolecules (proteins, fats, carbohydrates, nucleic acids) occurs mainly in the duodenum. II. The simple substances formed are absorbed in the jejunum and ileum regions of the small intestine. III. No significant digestive activity occurs in the large intestine. IV. Undigested and unabsorbed substances are temporarily stored in the caecum till defaecation.
Explanation: Statements I, II, and III are correct. Most chemical digestion occurs in the duodenum, while absorption of nutrients mainly occurs in the jejunum and ileum. No significant digestive activity occurs in the large intestine. Statement IV is incorrect because undigested wastes are temporarily stored in the rectum before defaecation.
Question 23 of 100
📘 CLASS XI
Read the following statements about infant digestion and select the correct combination:
I. Rennin is a proteolytic enzyme found in the gastric juice of infants which helps in digestion of milk proteins. II. Small amounts of lipases are also secreted by gastric glands in infants and adults. III. HCl in the infant stomach provides an optimum pH of 1.8 which is ideal for rennin activity. IV. Infant milk proteins are digested by trypsin in the mouth.
Explanation: Statements I and II are correct. Rennin present in infants helps digest milk proteins, and gastric glands secrete small amounts of lipase in both infants and adults. Statement III is incorrect because pH 1.8 is optimal for pepsin, not rennin. Statement IV is incorrect because trypsin is a pancreatic enzyme that acts in the small intestine, not in the mouth.
Question 24 of 100
📘 CLASS XI
Evaluate the statements regarding the movement of undigested food and select the correct set:
I. The undigested, unabsorbed substances called faeces enter into the caecum of the large intestine. II. The entry is regulated by the ileo-caecal valve which prevents the back flow of faecal matter. III. The egestion of faeces (defaecation) is an involuntary process carried out by mass peristaltic movement. IV. Faeces are temporarily stored in the caecum before defaecation.
Explanation: Statements I and II are correct. Faeces pass into the caecum through the ileo-caecal valve, which prevents backflow. Statement III is incorrect because defaecation is a voluntary process initiated by a neural reflex. Statement IV is incorrect because faeces are stored temporarily in the rectum before defaecation.
Question 25 of 100
📘 CLASS XI
Read the statements about the secretions released into the small intestine and choose the correct option:
I. The bile, pancreatic juice, and intestinal juice are all released into the small intestine. II. Pancreatic juice and bile are released through the hepato-pancreatic duct. III. Intestinal juice contains mucus along with bicarbonates from the pancreas to protect mucosa. IV. Intestinal juice contains nucleases which break down nucleic acids.
Explanation: Statements I, II, and III are correct. Bile, pancreatic juice, and succus entericus are released into the small intestine. Bile and pancreatic juice enter the duodenum through the common hepato-pancreatic duct. Mucus and pancreatic bicarbonates help protect the intestinal mucosa and maintain an alkaline pH. Statement IV is incorrect because nucleases are present in pancreatic juice, whereas intestinal juice contains nucleotidases and nucleosidases.
Question 26 of 100
📘 CLASS XI
Read the following statements regarding human salivary glands and select the correct combination:
I. The parotids are the largest salivary glands and are located in the cheek region. II. Sub-maxillary/sub-mandibular glands are located at the lower jaw. III. Sub-lingual glands are situated below the tongue. IV. These glands are located inside the buccal cavity and pour their secretions through ducts.
Explanation: Statements I, II, and III are correct as they accurately describe the location of the three pairs of human salivary glands. Statement IV is incorrect because these glands are situated just outside the buccal cavity, although they secrete saliva into it through ducts.
Question 27 of 100
📘 CLASS XI
With respect to the human liver, evaluate the correctness of the following statements:
I. It is the largest gland of the body, weighing about 1.2 to 1.5 kg in an adult human. II. It is situated in the thoracic cavity, just above the diaphragm. III. The hepatic lobules are the structural and functional units of the liver. IV. Each hepatic lobule is covered by a thin connective tissue sheath called Glisson's capsule.
Explanation: Statements I, III, and IV are correct. The liver is the largest gland in the body, hepatic lobules are its structural and functional units, and each lobule is covered by Glisson's capsule. Statement II is incorrect because the liver lies in the abdominal cavity just below the diaphragm.
Question 28 of 100
📘 CLASS XI
Read the following statements regarding the regions of the small intestine and identify the correct set:
I. The duodenum is a 'C' shaped structure where the exocrine pancreas opens. II. The jejunum is a long, highly coiled middle portion of the small intestine. III. The ileum is the highly coiled, terminal region of the small intestine that opens into the large intestine. IV. Glands are present in the sub-mucosa of the duodenum.
Explanation: Statements I, III, and IV are correct. The duodenum is C-shaped and contains Brunner's glands in its submucosa. The ileum is the highly coiled terminal part opening into the large intestine. Statement II is incorrect because the jejunum is described as a long coiled middle portion, whereas the ileum is highly coiled.
Question 29 of 100
📘 CLASS XI
Which of the following statements regarding the mucosal cells of the human stomach is/are correct?
I. Mucus neck cells secrete alkaline mucus to protect the epithelium from HCl. II. Peptic or chief cells secrete the active proteolytic enzyme pepsin. III. Parietal or oxyntic cells secrete hydrochloric acid (HCl). IV. Oxyntic cells secrete intrinsic factor, which is essential for the absorption of vitamin B12.
Explanation: Statements I, III, and IV are correct. Mucus neck cells secrete mucus that protects the gastric epithelium. Oxyntic cells secrete HCl and intrinsic factor required for vitamin B12 absorption. Statement II is incorrect because chief cells secrete pepsinogen, the inactive precursor of pepsin.
Question 30 of 100
📘 CLASS XI
Assess the correctness of the following statements regarding saliva and its chemical action in the oral cavity:
I. Chemical digestion of food is initiated in the oral cavity by salivary amylase. II. Salivary amylase hydrolyses starch into glucose molecules directly. III. About 30 percent of starch is hydrolysed in the oral cavity at an optimum pH of 6.8. IV. Lysozyme present in saliva acts as an antibacterial agent that prevents infections.
Explanation: Statements I, III, and IV are correct. Salivary amylase initiates carbohydrate digestion, hydrolysing about 30% of starch at an optimum pH of 6.8. Lysozyme acts as an antibacterial agent. Statement II is incorrect because salivary amylase converts starch mainly into maltose and dextrins, not directly into glucose.
