Chapter 65 - Guyton

Question 1

The chemistry of digestion is simple because, in the case of all three major types of food, the same basic process of ________ is involved.

Answer 1

hydrolysis

Question 2

Major carbohydrates in the diet.

Answer 2

sucrose, lactose, starches

Question 3

ptyalin

Answer 3

alpha-amylase (secreted mainly by the parotid gland)

Question 4

Represents more than 80% of the final products of carbohydrate digestion.

Answer 4

glucose

Question 5

What is the importance of pepsin in protein digestion?

Answer 5

it can break down collagen, the primary binding constituent of intracellular connective tissue of meats

Question 6

Within 15-30 minutes after the chyme empties from the stomach into the duodenum and mixes with pancreatic juice, virtually all the ___________ will have become digested.

Answer 6

carbohydrates (pancreatic juice has high amylase which will complete CHO digestion)

Question 7

Lactose

Answer 7

glucose + galactose

Question 8

Sucrose

Answer 8

glucose + fructose

Question 9

Maltose

Answer 9

glucose + glucose

Question 10

Where are lactase, sucrase, and maltase located?

Answer 10

in the enterocytes covering the intestinal microvilli brush border

Question 11

Most protein digestion occurs under the influence of proteolytic enzymes from pancreatic secretion..where does this occur?

Answer 11

in the upper small intestine, in the duodenum and jejunum

Question 12

This enzyme is important in the final stage of protein digestion occurring in the cytosol of the enterocyte (cleaving the tripeptides and dipeptides into amino acids).

Answer 12

peptidase

Question 13

Most abundant fats of the diet.

Answer 13

triglycerides

Question 14

Perform the detergent function for the digestion of fats.

Answer 14

bile salts and lecithin

Question 15

The most important enzyme for the digestion of triglycerides.

Answer 15

pancreatic lipase

Question 16

The bile salt _______ act as a transport medium to carry the monoglycerides and free fatty acids to the brush borders of the intestinal epithelial cells.

Answer 16

micelles

Question 17

valvulae conniventes (or folds of Kerckring)

Answer 17

increase the surface area of the absorptive mucosa of the small intestine

Question 18

Which three structures increase the absorptive surface area of the mucosa.

Answer 18

folds of Kerckring, villi, microvilli

Question 19

Water is transported through the intestinal membrane entirely by?

Answer 19

diffusion

Question 20

When a person becomes dehydrated, this hormone is secreted and greatly increases sodium (and water) reabsorption throughout the intestinal tract.

Answer 20

aldosterone

Question 21

Bicarbonate secreted by the intestinal membrane is often exchanged for absorption of which ion?

Answer 21

chloride

Question 22

This hormone activates vitamin D and then vitamin D causes increased calcium absorption.

Answer 22

parathyroid hormone

Question 23

Glucose is actively transported inside the cell by what mechanism?

Answer 23

sodium co-transport

Question 24

Fructose and a few amino acids do not require sodium co-transport but instead are absorbed through which mechanism?

Answer 24

facilitated diffusion

Question 25

How are short and medium-chain fatty acids absorbed?

Answer 25

direct diffusion of these short-chain fatty acids from the intestinal epithelial cells directly into the capillary blood of the intestinal villi (do not require lymphatics)

Question 26

How are triglycerides ultimately absorbed?

Answer 26

micelles to get into cells then released in the form of chylomicrons through the base of the epithelial cell, to flow upward through the thoracic lymph duct and empty into the circulating blood

Question 27

The primary function of the proximal colon versus distal?

Answer 27

absorption; storage

Question 28

Absorption of sodium and chloride ions creates an osmotic gradient across the large intestinal mucosa, which in turn causes absorption of?

Answer 28

water