CBSE Questions for Class 11 Medical Biology Digestion And Absorption Quiz 14 - MCQExams.com

• The salivary juice from the glands to the oral cavity moves through the salivary duct. 
• The parotid gland and the buccal mucosa is connected by the parotid duct (Stensen duct). 
• The submandibular duct (Wharton duct) connects the submandibular gland to the floor of the mouth. 
• The sublingual gland drains through numerous small ducts all of which open into the floor of the mouth and are collectively termed the duct of Rivinus. 

• Meckel's diverticulum is a bulge in the lower part (Ileum) of the small intestine. the bulge is congenital (present at birth) and is a leftover of the umbilical cord.
• Thus, Option A is correct.

• N-acetyl muramidase is also called as lysozyme.
•  This Lysozyme was discovered by Alexander Fleming in 1921 when he demonstrated that his own nasal mucus had the ability to inhibit the growth of a certain strain of bacteria in culture.
• This enzyme is found in the secretions of the lacrimal glands and in nasal mucus, gastric secretions, and egg white. 
• It catalyzes the breakdown of certain carbohydrates found in the cell walls of certain bacteria (e.g., cocci). Hence, N-Acetyl muramidase, active in saliva and is microbicidal, was discovered by Alexander Fleming.

• The cardiac sphincter, a circular muscle between the oesophagus and stomach, closes after food enters the stomach and prevents food from going back up into the oesophagus. 
• In some people, the cardiac sphincter does not function properly or it becomes weakened. 
• This leads to contents from the stomach leaking back into the oesophagus. 
• Stomach acids can irritate the oesophagus and cause symptoms of heartburn. 

• Incisors are the most anterior teeth. 
• Canines - all mammals have a single canine in each quadrant. 
• The premolars lie immediately posterior to the canines. 
• In the upper jaw, they are found in the maxillary. 
• The most posterior teeth in the jaws of most mammals are molars. 
• Humans have two incisors, one canine, two premolars, and three molars, I2 C1 P2 M3, in each quadrant of their upper jaws. 
• The numbers for each quadrant of the lower jaw are the same, and the general formula is written I2/2 C1/1 P2/2 M3/3. 

$$\textbf{Correct answer: B}$$  

$$\textbf{Option (A):}$$  

$$\bullet$$ Rabbit has its own stomach containing different digestive glands.

$$\bullet$$ This structure is similar to the other mammals even though rabbits are herbivorous.

$$\bullet$$ There are glands present on the lining of the intestine as well. 

$$\textbf{Option (B):}$$  

$$\bullet$$ The presence of villi in the stomach distinguishes it from the other structures of the alimentary canal. 

$$\bullet$$ It increases the surface area of the intestine and also helps with the fermentation of fibrous components of food. 

$$\textbf{Option (C):}$$  

$$\bullet$$ Submucosa in the intestine of the rabbit shows a similar character as that of the submucosa of the stomach.

$$\bullet$$ The secretory cells are present in this region in both structures. 

$$\textbf{Option (D):}$$  

$$\bullet$$ Serosa is the outer layer of the alimentary canal and it is similar in both structures. 

Hence, the correct answer is option (B).

• The digestion of starch begins with the action of salivary alpha-amylase/ptyalin. 
• The starch is further digested in the small intestine in the presence of pancreatic amylase. 
• Pancreas secretes lipase enzyme and liver secretes bile salts. in the presence of bile and pancreatic lipase, fat is emulsified and digested in the small intestine. 
• Protein digestion first starts in the stomach in the presence of pepsin enzyme. 
• Trypsinogen and chymotrypsinogen are produced in the pancreas which are inactive(zymogenic) proteases that, once activated in the duodenum gets converted to active trypsin and chymotrypsin further digest the protein into simple amino acids. 
• Chymosin, known also as rennin, is a proteolytic enzyme synthesized by chief cells in the stomach that curdle milk by transforming caseinogen into insoluble casein. 

Solution

Correct answer is option B

Explanation for correct option:

• Succus entericus, also called as intestinal juice, contains mucus and digestive enzymes, including enteropeptidase, lactase, and sucrase.
• Succus entericus is the alkaline secretion produced by glands in the duodenum wall of small intestine, specifically by crypts of Lieberkuhn.