CBSE Questions for Class 11 Medical Biology Digestion And Absorption Quiz 7 - MCQExams.com

• The small intestine is the part of the gastrointestinal tract between the stomach and the large intestine and is where much of the digestion and absorption of food takes place. 
• The small intestine is divided into three parts such as duodenum, jejunum, and ileum. 

1. The duodenum is a first part of the small intestine continuous with the stomach and shaped like a "C". 
2. The jejunum is the midsection of the small intestine, connecting the duodenum to the ileum. 
3. The ileum is the final section of the small intestine. 

$$\textbf{Correct answer: D}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ The stomach is modified to form a thin-walled structure called crop in some animals.

$$\bullet$$ It acts as the main organ in those animals for the storage of food.

$$\textbf{Option (B):}$$ 

$$\bullet$$ The proventriculus structure is the region where the highest secretion of enzyme takes place and the grinding takes place in the gizzard with proper digestion.

$$\textbf{Option (C):}$$ 

$$\bullet$$ Most of such organisms like birds release the waste products through the cloaca. This is their only structure for excretion.

$$\textbf{Option (D):}$$ 

$$\bullet$$ The gizzard which is an organ of the digestive system in some animals is also known as the gastric mill. 

$$\bullet$$ It is a specialized type of stomach that contains thick muscular walls that are responsible for grinding up food. 

$$\bullet$$ In certain animals, the gizzard contains chitinous plates or teeth which improves its function. 

Hence, the correct answer is option (D).

• A lacteal is one of the lymphatic capillaries that help to absorb dietary fats in the small intestine. 

The small intestine is the most important part of the digestive system where digestion and absorption of nutrients take place. The small intestine can be divided into 3 major regions. The first part is duodenum that connects the pyloric sphincter of the stomach. It is the shortest region of the small intestine, measuring only about 10 inches in length. The second part is the jejunum that serves as the primary site of nutrient absorption. It measures around 3 feet in length. The last part of small intestine is the ileum that is about 6 feet long and completes the absorption of nutrients that were missed in the jejunum

So, the correct answer is 'Last part of the small intestine'

$$\textbf{Correct answer: C}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ The intestinal juice which is secreted by the epithelial lining of the small intestine is called succus entericus.

$$\textbf{Option (B):}$$ 

$$\bullet$$ All the secretions from the different glands lining the walls of the small intestine form pale yellow secretions. It contains mucus which lubricates the epithelial structure.

$$\bullet$$ The bicarbonate present in it increases the acidic pH to an alkaline level.

$$\bullet$$ Lipase, maltase and nucleosidases are found in the succus entericus and secreted from the glandular cells of the small intestine. 

$$\bullet$$ Lipase facilitates the digestion of lipid to fatty acids and glycerol.

$$\bullet$$ Maltase is responsible for converting maltose into glucose. 

$$\textbf{Option (C):}$$ 

$$\bullet$$ Nucleases which can digest the nucleic acid molecules are not found in the intestinal juice.

$$\bullet$$ This includes endonuclease and an exonuclease which are not found in the small intestine.

$$\textbf{Option (D):}$$ 

$$\bullet$$ Nucleosidase helps in the digestion of nucleic acids.

Hence, the correct answer is option (C).