Digestion, Absorption, and Metabolism Flashcards Preview

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Flashcards in Digestion, Absorption, and Metabolism Deck (29)
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The process of digestion involves _____ and _____ actions.

mechanical, chemical

For nutrients to be delivered to the cells, food goes through a series of mechanical and chemical changes.


The rhythmic contractions of the stomach and intestine that propel food along are called


is the alternating muscular contractions and relaxations that force the contents forward through the gastrointestinal tract.


An example of a gastric secretion is

hydrochloric acid.

Gastric secretions work together to make chemical digestion possible. Five types of substances are involved, including enzymes, hydrochloric acid and buffer ions, mucus, water and electrolytes, and bile. In this case, hydrochloric acid is the gastric secretion.


A pizza slice is being consumed by a hungry teen. The first actions of biting, chewing, and breaking up the slice into smaller particles is called


begins mechanical digestion in the mouth. Mastication is the biting and chewing that begins to break food into smaller particles.


A food that begins digestion in the mouth is


In the mouth, salivary glands secrete salivary amylase, which is the general name for any starch-splitting enzyme. Thus a food with starch content, such as bread, could begin its chemical digestion in the mouth.


After a period of mixing and churning of the ingested food with the gastric secretions, the semifluid mass is called


By the time the food mass reaches the lower portion of the stomach, it is a semiliquid, acid-food mix called chyme.


The release of gastric secretions is stimulated by

nerves, hormones, and the presence of food in the stomach.

Gastric secretions are stimulated by nerves, hormones, and the presence of food in the stomach.


One type of movement in the small intestine is


The intestinal muscles produce several types of movement that aid digestion, including peristaltic, pendular, segmental rings, longitudinal rotation, and surface villi motions.


Compared with the pH in the stomach, the pH in the small intestine is


The pH of the stomach is acidic and the pH of the small intestine is alkaline.


A meal of barbequed chicken, herbed rice, and green beans requires what enzyme to digest the chicken?


Carboxypeptidase, aminopeptidase, and dipeptidase are enzymes that break down protein to amino acids.


A food that is ultimately broken down by trypsin is


Trypsin breaks down protein to dipeptides. In this case, chicken is the protein food.


The lining of the stomach and intestine is protected from strong acid by


Large quantities of mucus are secreted by the intestinal glands to protect the mucosal lining from irritation and erosion caused by the high acidic gastric contents entering the duodenum. Because the stomach contains hydrochloric acid, mucus is available to protect its lining from the erosive effects of the acid.


The hormone that stimulates the pancreas to release its secretions is


The hormone secretin, which is produced by the mucosal glands in the first part of the intestine, controls the acidity and secretion of enzymes from the pancreas.


A meal consisting of country fried steak, carrots, and a baked potato with butter and sour cream would stimulate the hormone cholecystokinin because of the

presence of fat in the duodenum.

The stimulus for the release of cholecystokinin is the present of fat in the duodenum. Once stimulated, cholecystokinin stimulates the gallbladder to release bile to emulsify fat.


After eating a meal consisting of fried chicken, peas, and carrots, the end products of the digestion of fat from the fried chicken include

glycerol and fatty acids.

The end products of digestion of fats are glycerol and fatty acids. Intestinal lipase splits fat into glycerides and fatty acids.


A means of absorption that occurs in the small intestine is


Simple diffusion, facilitated diffusion, active diffusion, and pinocytosis are the processes by which nutrients cross the inner intestinal wall and into the body circulation. Pinocytosis is the penetration of larger materials by attaching to the thicker cell membrane and being engulfed by the cell.


After absorption, the end products of carbohydrate and protein digestion enter the

blood system.

Once carbohydrates and protein are digested and absorbed, they cross the inner intestinal wall and enter the bloodstream.


The primary nutritional function of the large intestine is

absorption of water.

The primary function of the large intestine is to absorb water from the chyme. The water is absorbed in the first half of the colon.


Bacteria found in the colon are significant because they

synthesize some vitamins.

Vitamin K is synthesized from bacteria in the large intestine.


Gas formation in the colon is the result of

bacterial action on undigested items.

Bacterial action on indigestible food items in the large intestine can contribute to the formation of gas.


After digestion, fatty materials are absorbed into the


Because fatty materials are not water soluble, these molecules pass into the lymph vessels in the villi (e.g., the lacteals), then into the larger lymph vessels of the body, and eventually into the bloodstream.


Digestion of dietary fiber occurs in the
a. stomach.
b. small intestine.
c. large intestine.
d. none of the above.

none of the above.

Food fiber is not digested because human beings lack the specific enzymes required.


The sum total of all the chemical changes that an organism performs to maintain its life and produce energy is the result of


Metabolism is the sum total of all chemical changes that take place in the body by which it maintains itself and produces energy for its functioning.


Bile contains


Bile is an emulsifying agent that aids in fat digestion and absorption.


Two organs that work with the small intestine in digestion are the

pancreas and liver.

The pancreas aids in digestion by secreting enzymes to aid in protein, carbohydrate, and fat digestion. As part of the hepatobiliary system, the presence of fat in the small intestine triggers the release of bile from the gallbladder.


Conversion of amino acids to glucose is called



The surface of the intestinal wall has mucosal folds, villi, and microvilli to

increase the surface area for absorption.

Mucosal folds, villi, and microvilli combine to make the inner surface some 600 times greater than the area of the outer surface of the intestine.


Ways to minimize formation of stomach gas include

not gulping.

Stomach gas can be minimized by avoiding carbonated beverages, chewing with the mouth closed, not gulping food, not drinking from a can or through a straw, and not eating while nervous.


A beverage that may cause intestinal gas in adults is


Many people lack the enzyme lactase to digest milk.