Digestion and Absorption Test - 38

Solution

Correct answer is option B.

Explanation for correct option:

• The first segment of the duodenum—the superior part of the duodenum (called the duodenal bulb) is connected to the liver via the hepatoduodenal ligament.
• This connection allows for transportation of nutrients from the small intestine to the liver; it also allows the duodenum to receive bile from the liver.

• Food is digested in stomach and small intestine, Whereas digested food is absorbed by the small intestine.
• The large intestine is the last part of the digestive system where the absorption of water takes place.
• After the absorption of water, the left solid materials are excreted out as feces
  
  Thus, the correct answer is option C.

• correct answer is option D.
  
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• The small intestine is the most important part of the alimentary canal for digestion and absorption of food. 
• It has three regions a U-shaped duodenum, a long coiled middle portion jejunum and highly coiled ileum.
• The innermost layer lining the lumen of the alimentary canal is the mucosa. This layer forms irregular folds (rugae) in the stomach and small finger-like foldings called villi in the small intestine. 
• These modifications increase the surface area for more absorption. Villi are supplied with a network of capillaries and a large lymph vessel called the lacteal.
• It transports lipid molecules. The wall of the intestine is surrounded by the blood vessels which assimilates the food molecules to the different parts of the body.
  
  

The gastric juice is made up of hydrochloric acid, pepsinogen and other digestive enzymes, gastrin, mucus, and bicarbonates. It has a pH ranging from 1 to 2. Its low pH is essential in activating digestive enzyme such as pepsinogen and convert it into the active pepsin, a Proteolytic activity of pepsin and in destroying various pathogens. 

Solution

Correct answer is option A.

Explanation for correct option:

• Digestive enzymes play a key role in breaking down the food.
• For example, there are enzymes in our saliva, pancreas, intestines and stomach. They break down fats, proteins and carbohydrates into simpler forms.
• The enzymes break down the food into nutrient pieces until they are small enough to be absorbed into the bloodstream and carried throughout the body.

• Most of the digestion and absorption of the food takes place in the small intestine because it is the main organ of absorption and digestion of food. 
• The surface area of the small intestine gets increased for absorption due to the presence of villi which gives food plenty of time to break down properly. Hence, the longest part of the alimentary canal is a small intestine.

So, the correct answer is 'Small intestine'.