Question 1

Which layer of the small intestine is primarily responsible for nutrient absorption, and what structural feature increases its surface area for this function?

Accepted Answer

Mucosa; presence of villi and microvilli

Question 2

Which hormone is released in response to fatty chyme in the small intestine and what is its primary effect on digestion?

Accepted Answer

Cholecystokinin (CCK); stimulates bile and pancreatic enzyme release

Question 3

What is the correct sequence for the activation of pancreatic proteases in the small intestine?

Accepted Answer

Trypsinogen is activated by enteropeptidase, then trypsin activates other proteases

Question 4

Which process best describes how glucose is absorbed from the lumen of the small intestine into the blood?

Accepted Answer

Secondary active transport with Na+ into enterocytes, then facilitated diffusion into blood

Question 5

Which of the following best explains why most pancreatic enzymes are secreted in an inactive form?

Accepted Answer

To prevent self-digestion of the pancreas and its ducts

Question 6

Which of the following is a correct statement about the absorption of lipids in the small intestine?

Accepted Answer

Chylomicrons are absorbed into lymphatic lacteals

Question 7

Which of the following best describes the role of the myenteric plexus in the gastrointestinal tract?

Accepted Answer

It regulates motility by innervating the muscularis layer

Question 8

A patient has a genetic defect that prevents the production of intrinsic factor in the stomach. Which nutrient absorption will be most affected?

Accepted Answer

Vitamin B12

Question 9

Which of the following best explains why carbohydrate-rich meals are digested and absorbed more quickly than lipid-rich meals?

Accepted Answer

Carbohydrates require fewer types of secretions and less controlled motility

Question 10

Which of the following is a direct effect of secretin released from the small intestine?

Accepted Answer

Stimulates release of pancreatic bicarbonate

Question 11

Which of the following best describes the fate of absorbed amino acids in the liver during the absorptive phase?

Accepted Answer

They are used for protein synthesis, ATP production, and lipoprotein formation

Question 12

Which of the following best describes the main function of the electron transport chain in mitochondria?

Accepted Answer

To produce ATP by using the energy from high-energy electrons to create a proton gradient

Question 13

Which metabolic pathway is favored during the postabsorptive (unfed) state to maintain blood glucose levels?

Accepted Answer

Glycogenolysis and gluconeogenesis

Question 14

Which hormone is secreted by pancreatic alpha cells and what is its primary effect?

Accepted Answer

Glucagon; stimulates glycogenolysis and gluconeogenesis

Question 15

Which of the following best explains why the number of mitochondria in a cell can change independently of cell division?

Accepted Answer

Mitochondria have their own DNA and can divide in response to metabolic demand

Question 16

Which of the following is a key intermediate in glycolysis that can be used for entry of other biomolecules into ATP synthesis pathways?

Accepted Answer

Glucose-6-phosphate

Question 17

Which process is responsible for the conversion of fatty acids to acetyl CoA in the mitochondria?

Accepted Answer

$$\beta-$$oxidation

Question 18

A patient is unable to absorb fat-soluble vitamins efficiently. Which digestive process is most likely impaired?

Accepted Answer

Emulsification of lipids by bile salts

Question 19

Which of the following best describes the effect of insulin on glucose transport in non-hepatic cells?

Accepted Answer

Insulin triggers insertion of GLUT transporters into the cell membrane

Digestive System and Metabolism: Anatomy & Physiology Study Guide

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