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: Which is a function of the liver in human adults?

A. manufacturing red blood cells

B. producing chemical compounds known as auxins

C. storing the carbohydrate reserve glycogen

D. synthesizing the hormone insulin

Answer Explanation

C) storing the carbohydrate reserve glycogen

- Correct: One of the functions of the liver in human adults is storing the carbohydrate reserve glycogen. Glycogen is a polysaccharide that serves as a storage form of glucose in the body. When blood glucose levels are high, such as after a meal, the liver takes up excess glucose and converts it into glycogen for storage. When blood glucose levels drop, such as between meals or during fasting, the liver breaks down glycogen and releases glucose into the bloodstream to maintain blood sugar levels within a normal range.

A) manufacturing red blood cells

- Incorrect: The primary site of red blood cell production (erythropoiesis) in adults is the bone marrow, not the liver. While the liver is involved in the production of blood proteins and components, such as albumin, clotting factors, and plasma proteins, it is not responsible for manufacturing red blood cells.

B) producing chemical compounds known as auxins

- Incorrect: Auxins are a class of plant hormones involved in various physiological processes, such as cell elongation, apical dominance, and root development. They are not produced by the liver in human adults.

D) synthesizing the hormone insulin

- Incorrect: Insulin is a hormone produced by the pancreas, not the liver. Insulin plays a crucial role in regulating blood sugar levels by facilitating the uptake of glucose into cells for energy production or storage. While the liver responds to insulin by regulating glucose metabolism and storage, it does not synthesize insulin itself.
Q #2: Which of the following organs is supported by a layer of adventitia rather than serosa?

A. esophagus

B. stomach

C. small intestine

D. large intestine

Answer Explanation

a) esophagus

- Correct: The esophagus is supported by a layer of adventitia rather than serosa. The adventitia is a connective tissue layer that covers organs and structures that are not located within the peritoneal cavity. In the case of the esophagus, it lies behind the trachea and heart and passes through the diaphragm before connecting to the stomach. Since it is located outside the peritoneal cavity, it is covered by adventitia instead of serosa, which is the visceral peritoneum that covers organs within the abdominal cavity.

b) stomach

- Incorrect: The stomach is supported by a layer of serosa, which is the visceral peritoneum covering organs within the abdominal cavity.

c) small intestine

- Incorrect: The small intestine is supported by a layer of serosa, which is the visceral peritoneum covering organs within the abdominal cavity.

d) large intestine

- Incorrect: The large intestine is supported by a layer of serosa, which is the visceral peritoneum covering organs within the abdominal cavity.
Q #3: A disorder of the digestive system that can cause severe dehydration is known as

A. appendicitis

B. gallstones

C. constipation

D. diarrhea

Answer Explanation

D) diarrhea

- Correct: Diarrhea is a disorder of the digestive system that can cause severe dehydration. Diarrhea is characterized by frequent, loose, or watery bowel movements, often accompanied by abdominal cramps, bloating, and urgency. It occurs when the intestines fail to properly absorb water or when excess fluid is secreted into the intestines. Diarrhea can lead to significant fluid loss and electrolyte imbalance, resulting in dehydration, particularly if not promptly treated by replenishing lost fluids and electrolytes.

A) appendicitis

- Incorrect: Appendicitis is inflammation of the appendix, a small pouch located near the junction of the small and large intestines. While appendicitis can cause symptoms such as abdominal pain, fever, and vomiting, it is not directly associated with dehydration.

B) gallstones

- Incorrect: Gallstones are hardened deposits that form in the gallbladder and can cause symptoms such as abdominal pain, nausea, and jaundice. While gallstones can lead to complications such as obstruction of the bile duct, they are not directly associated with dehydration.

C) constipation

- Incorrect: Constipation refers to infrequent bowel movements or difficulty passing stool, often characterized by hard, dry stools that are difficult to pass. While severe constipation can cause discomfort and complications such as fecal impaction, it is not directly associated with dehydration.

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

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Q #1: Which is a function of the liver in human adults?

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Q #2: Which of the following organs is supported by a layer of adventitia rather than serosa?

Answer Explanation

Q #3: A disorder of the digestive system that can cause severe dehydration is known as

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