Question 1

Which of the following best describes the process of peristalsis in the digestive tract?

Accepted Answer

Coordinated, wave-like contractions of circular and longitudinal smooth muscle layers that propel contents along the digestive tract.

Question 2

Which tissue type lines the mucosa of the pharynx and esophagus, and why is this significant?

Accepted Answer

Stratified squamous epithelium; it protects against abrasion from food passage.

Question 3

Which of the following correctly lists the three major pairs of salivary glands and the type of saliva each produces?

Accepted Answer

Parotid (serous), submandibular (mixed serous and mucous), sublingual (mucous)

Question 4

What is the primary function of rugae in the stomach?

Accepted Answer

To allow the stomach to expand after eating a meal.

Question 5

During the formation of gastric acid, which equation best represents the chemical reaction occurring in parietal cells?

Accepted Answer

$$\mathrm{CO_2$ + H_2O \rightarrow H_2CO_3 \rightarrow H^+ + $$HCO_3$$^-}$$

Question 6

Which phase of gastric activity is primarily stimulated by the sight, smell, or thought of food?

Accepted Answer

Cephalic phase

Question 7

Which of the following best describes the alkaline tide?

Accepted Answer

A temporary increase in blood pH due to the absorption of bicarbonate ions after gastric acid secretion.

Question 8

Which structure in the small intestine is primarily responsible for increasing surface area to maximize nutrient absorption?

Accepted Answer

Villi and microvilli

Question 9

How does the wall of the colon differ from the rest of the digestive tract?

Accepted Answer

It has three distinct bands of longitudinal muscle called teniae coli.

Question 10

Which of the following correctly traces the path of bile from a liver lobule to the duodenal papilla?

Accepted Answer

Bile canaliculi → hepatic duct → cystic duct → common bile duct → duodenal papilla

Question 11

Which equation best represents the interaction between an enzyme and its substrate?

Accepted Answer

$$\mathrm{E + S \rightarrow ES \rightarrow E + P}$$

Question 12

Which of the following lists the correct order of enzymes secreted for carbohydrate digestion, along with their sources?

Accepted Answer

Salivary amylase (salivary glands) → pancreatic amylase (pancreas) → maltase, sucrase, lactase (small intestine)

Question 13

Which digestive hormone stimulates the release of bile from the gallbladder and pancreatic enzymes into the small intestine?

Accepted Answer

Cholecystokinin (CCK)

Question 14

How are carbohydrates absorbed into the capillaries of the villi?

Accepted Answer

By active transport and facilitated diffusion as monosaccharides.

Question 15

Which of the following best describes the chemical composition of lipids?

Accepted Answer

Glycerol backbone bonded to fatty acids via ester bonds.

Question 16

What is the role of bile in lipid digestion?

Accepted Answer

It emulsifies fats, increasing their surface area for enzyme action.

Question 17

Which structure in the villi is responsible for the absorption of lipids, and what is the role of micelles and chylomicrons in this process?

Accepted Answer

Lacteals; micelles deliver lipids to enterocytes, which package them into chylomicrons for transport in lymph.

Question 18

Which of the following lists the correct order of enzymes secreted for protein digestion, including activation steps?

Accepted Answer

Pepsinogen (stomach, activated to pepsin by HCl) → trypsinogen (pancreas, activated to trypsin by enterokinase) → chymotrypsinogen (pancreas, activated to chymotrypsin by trypsin)

Question 19

How are proteins absorbed into the capillaries of the villi?

Accepted Answer

As amino acids by active transport and facilitated diffusion.

Digestive System: Anatomy, Physiology, and Chemistry of Digestion Study Guide

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