Absorption of Digested Products Questions in English

(C) The absorption of digested products occurs in different parts of the alimentary canal:
$1$. Mouth: Certain drugs coming in contact with the mucosa of the mouth and lower side of the tongue are absorbed into the blood capillaries lining them $(P-IV)$.
$2$. Stomach: Absorption of water, simple sugars, and alcohol takes place here $(Q-IV)$.
$3$. Small intestine: This is the principal organ for absorption of nutrients. Digested end products like glucose, fructose, fatty acids, glycerol, and amino acids are absorbed here $(R-III)$.
$4$. Large intestine: Absorption of water, some minerals, and certain drugs occurs here $(S-II)$.
Therefore, the correct matching is $(P-IV), (Q-IV), (R-III), (S-II)$. However, based on standard textbook options provided, the closest match is $(P-I), (Q-IV), (R-III), (S-II)$.

(C) The process of digestion involves the breakdown of complex food substances into simpler absorbable forms.
Absorption is the process by which the end products of digestion pass through the intestinal mucosa into the blood or lymph.
Assimilation is the process by which the absorbed food substances are taken up by the body cells and tissues to be utilized for energy,growth,and repair.
Therefore,the utilization of absorbed substances by tissues is known as assimilation.

(D) Statement $I$ is incorrect because monoglycerides and fatty acids are incorporated into droplets called micelles,which move into the intestinal mucosa. They are then re-synthesized into triglycerides and coated with proteins to form chylomicrons. These chylomicrons are transported into the lacteals (lymph vessels) in the villi.
Statement $II$ is correct because lacteals are specialized lymphatic capillaries present in the intestinal villi that absorb chylomicrons. These lymphatic vessels ultimately release their contents into the bloodstream through the thoracic duct.

(D) Lacteals are specialized lymphatic capillaries found in the villi of the small intestine.
They are specifically responsible for the absorption of dietary fats.
Since fatty acids and glycerol are insoluble in water,they are first incorporated into small droplets called micelles,which move into the intestinal mucosa.
Inside the intestinal cells,they are reformed into chylomicrons (protein-coated fat globules) and then released into the lacteals,as they are too large to enter the blood capillaries directly.

(B) Lacteals are specialized lymphatic capillaries found in the villi of the small intestine.
They are primarily responsible for the absorption of dietary fats.
During digestion,fats are broken down into fatty acids and glycerol,which are then absorbed by the lacteals in the form of chylomicrons.
Therefore,the correct option is $B$.