Digestion And Absorption

Question

A student observing the inner lining of the small intestine notes numerous finger-like projections; what is the principal functional advantage these structures provide to the body?

RankGuru · Accepted Answer

The finger-like projections described are the villi of the small intestinal mucosa, and their cells additionally bear microvilli on their free surface. NCERT Class 11, Chapter 16 (Digestion and Absorption) emphasises that villi and microvilli together produce an enormous absorptive surface area, allowing efficient uptake of the end products of digestion such as glucose, amino acids, fatty acids and glycerol. Each villus is richly supplied with blood capillaries and a lacteal, so absorbed nutrients are immediately carried into the circulation or lymph. Secretion of hydrochloric acid is incorrect because HCl is produced by oxyntic (parietal) cells of the gastric glands in the stomach, not by intestinal villi. Mechanical churning of food is achieved by muscular contractions of the stomach and peristalsis, not by mucosal folds. Storage of undigested cellulose does not occur in the small intestine; cellulose passes largely undigested to the large intestine, where it adds roughage. The defining role of villi is therefore absorptive. A sanity check supports this: organs specialised for absorption universally maximise surface area, exactly as the villi and microvilli accomplish in the small intestine.

Digestion And Absorption

Select the correct option:

🔒 Solution Hidden from View

More human physiology Practice Questions

During digestion of a fatty meal, bile salts released into the duodenum chiefly assist fat breakdown...

Inactive trypsinogen secreted by the pancreas must be converted to active trypsin before protein dig...

Following a carbohydrate-rich meal, blood glucose rises sharply; the pancreatic hormone secreted to ...

Inside red blood cells carbon dioxide is converted to bicarbonate, and chloride ions move inward to ...

In a standard electrocardiogram recorded from a healthy individual, the QRS complex of the tracing p...

According to the sliding filament theory of muscle contraction, the observable shortening of a sarco...

The resting neuronal membrane maintains a particular distribution of ions, being relatively impermea...

Given that a heart ejects a stroke volume of 70 mL with each beat while beating 72 times every minut...

During the cross-bridge cycle in skeletal muscle, the regulatory protein that blocks myosin-binding ...

A fall in blood pressure within the afferent arteriole stimulates a specialised cellular complex of ...

A patient suffers from a progressive autoimmune disorder in which fatigue and weakness of skeletal m...

Considering that both kidneys together form filtrate at roughly 125 mL per minute, approximately wha...

About This Question

Solution