Most of the nutrient absorption along the alimentary canal occurs in the

A. ascending colon

B. stomach

C. jejunum

D. ileum

Answer Explanation:

C. jejunum

- Correct: Most of the nutrient absorption along the alimentary canal occurs in the jejunum, which is the middle segment of the small intestine. The jejunum has a highly folded inner surface covered with finger-like projections called villi and even smaller microvilli. These structures greatly increase the surface area available for absorption. The epithelial cells lining the villi contain numerous transport proteins and enzymes responsible for absorbing nutrients such as carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream for distribution to the body's cells.

A. ascending colon

- Incorrect: The ascending colon is part of the large intestine (colon) where water and electrolytes are primarily absorbed, but it is not a major site of nutrient absorption.

B. stomach

- Incorrect: While some substances, such as water, electrolytes, alcohol, and certain drugs, can be absorbed in small amounts in the stomach, the stomach is not a major site of nutrient absorption. Its main function is to begin the digestion of proteins and store food temporarily.

D. ileum

- Incorrect: The ileum is the final segment of the small intestine, and while it does participate in nutrient absorption, the majority of nutrient absorption occurs in the jejunum, which precedes the ileum along the alimentary canal. The ileum primarily absorbs bile salts, vitamin B12, and some remaining nutrients not absorbed in the jejunum.

Therefore, the Correct Answer is C.

Q #1: The small intestine possesses permanent folds along its length known as

A. plicae circulares

B. haustra

C. villi

D. intestinal crypts

Answer Explanation

A. plicae circulares

- Correct: The small intestine possesses permanent folds along its length known as plicae circulares, also called circular folds or valvulae conniventes. These folds are permanent transverse ridges of the mucosa and submucosa that project into the lumen of the small intestine. They increase the surface area for absorption and digestion by slowing the passage of chyme and increasing contact between chyme and the intestinal lining, facilitating nutrient absorption.

B. haustra

- Incorrect: Haustra are pouches or sacculations formed by the muscularis externa of the colon (large intestine), not the folds of the small intestine.

C. villi

- Incorrect: Villi are finger-like projections of the mucosa of the small intestine that extend into the lumen. While villi increase the surface area for absorption, they are not permanent folds along the length of the small intestine.

D. intestinal crypts

- Incorrect: Intestinal crypts, also known as crypts of Lieberkühn, are invaginations of the epithelium located between villi in the mucosa of the small intestine. They contain stem cells that continuously divide and give rise to new epithelial cells, helping to replenish the epithelial lining of the intestine. Crypts are not permanent folds along the length of the small intestine.
Q #2: Which part of the large intestine attaches to the appendix?

A. cecum

B. ascending colon

C. transverse colon

D. descending colon

Answer Explanation

Cecum attaches to the appendix
Q #3: Which of the following organs has 3 layers of smooth muscle in its muscularis externa?

A. small intestine

B. esophagus

C. stomach

D. large intestine

Answer Explanation

C. stomach

- Correct: The stomach has three layers of smooth muscle in its muscularis externa, which is the muscular layer of the gastrointestinal tract responsible for peristalsis and mixing of food. These muscle layers are arranged in longitudinal, circular, and oblique orientations, allowing for the mechanical processing of ingested food and the propulsion of food through the digestive tract. This muscular arrangement contributes to the stomach's ability to churn and mix food with gastric juices during digestion.

A. small intestine

- Incorrect: While the small intestine does have smooth muscle in its muscularis externa, it typically has two layers of smooth muscle: an inner circular layer and an outer longitudinal layer.

B. esophagus

- Incorrect: The esophagus also has smooth muscle in its muscularis externa, but it typically has two layers of smooth muscle: an inner circular layer and an outer longitudinal layer.

D. large intestine

- Incorrect: The large intestine, like the small intestine, typically has two layers of smooth muscle in its muscularis externa: an inner circular layer and an outer longitudinal layer.

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Most of the nutrient absorption along the alimentary canal occurs in the

More Questions on TEAS 7 Science

Q #1: The small intestine possesses permanent folds along its length known as

Answer Explanation

Q #2: Which part of the large intestine attaches to the appendix?

Answer Explanation

Q #3: Which of the following organs has 3 layers of smooth muscle in its muscularis externa?

Answer Explanation

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