Question

What is the name of a finger-like projection in the small intestine of humans?
(a)Vermiform appendix.
(b)Villi
(c)Gizzard
(d)Food vacuole

Answer 1

Hint: This is the finger-like projection in the wall of the small intestine to increase the total surface area for the absorption of nutrients after the food has been digested. These are much smaller than any of the circular folds in the intestine.

Complete answer:
The finger-like projections in the small intestine of humans are known as villi. The shape of the villi is to extend into the lumen of the small intestine. It has many microvilli projecting from the enterocytes of its epithelium and each of these microvilli is about 1 µm in length, and also around 1000 times shorter than a single villus. Villi increases the internal surface area of the intestinal walls so that a greater surface area will be available for absorption.

Additional Information:
-In the small intestine, the increased absorptive area is very useful because digested nutrients pass into the semipermeable villi through diffusion, which is effective only at short distances. In other words, an increase in the surface area decreases the average distance traveled by nutrient molecules, so the effectiveness of diffusion also increases. The villi are connected to the blood vessels so the absorbed nutrients are carried by the blood to the entire body.
-Vermiform appendix: It is a small pouch-like sac of tissue that is located in the first part of the colon in the lower right abdomen.
-Gizzard: It is a muscular, thick-walled part of the stomach of birds, fish, insects, mollusks, and other invertebrates. for grinding food, typically with grit.
-Food vacuole: These are membrane-bound sacs within a cell, which contain food matter to be digested. These are considered as an intracellular stomach where food is stored while it is broken down and its nutrients are extracted.

So, the correct answer is ‘Villi’.

Note:
-The villi and the microvilli increase the intestinal surface area for absorption provides exceptionally efficient absorption of nutrients in the lumen.
-Some enzymes are also present on the surface for digestion.
-Villus capillaries collect amino acids and simple sugars taken up by the villi into the bloodstream. -lymph capillary of the villus collect absorbed chylomicrons, which are lipoproteins composed of triglycerides, cholesterol, and amphipathic proteins, and are taken to the rest of the body through the lymph fluid.