ch 25 digestive mcgraw

Chemical digestion is a series of chemical reactions that break large chunks of food into proteins, carbohydrates, and fats.

false

The medulla oblongata controls gastric secretion by utilizing the parasympathetic branch of the nervous system and the endocrine system.

false

The term contact digestion refers to the fact that segmentation must occur in order to propel intestinal contents distally within the digestive tract.

false

Mass movements in the colon are stimulated by the presence of __________ in the __________.

food in stomach .. feces in rectum

Which of the following hormones does not inhibit gastric gland secretions?

gastrin

The hormone __________ stimulates the secretion of the enzyme __________ in the stomach.

gastrin; pepsinogen

Blood sugar refers to circulating levels of __________ in the blood.

gluclose

Cholecystokinin, which is produced in the small intestine, inhibits gastric secretions in the stomach.

true

Distention of the stomach activates a direct stimulatory effect on the gastric glands.

true

Gastrin functions to increase the production of HCl in the stomach.

true

In the parietal cell, carbonic acid dissociates into a bicarbonate ion and a hydrogen ion.

true

Mass movements of the colon propel its contents toward the rectum.

true

Secretin is released from the duodenum in response to acidic chyme.

true

When two different people consume the same food, it is possible that one receives a different number of calories from that food because of differing bacterial populations in the large intestine.

true

Mass movements of the colon occur __________ times per day.

1 to 3

Which of the following occurs during the gastric phase of gastric secretion?

All of these take place in the gastric phase.

How does sucrose change the configuration of sucrase?

By binding to the active site

Which of the following inhibits the secretion of the gastric glands?

Duodenal pH of less than two

In which direction do the peristaltic contractions of the stomach's smooth muscle move contents?

From the fundus to the pylorus

Where is sucrase found in the human body?

On the microvilli of the small intestine

Which of the following statements is true regarding sucrase?

Sucrase breaks sucrose into glucose and fructose.

Ion exchange molecules in the plasma membrane of the parietal cells exchange __________ ions going out for __________ ions coming in.

bicarbonate; chloride

In order for digestion to occur, chyme is required to contact the microvilli of the intestinal wall because the __________.

brush border enzymes are not secreted into the lumen

In the parietal cells, the enzyme carbonic anhydrase causes a reaction between __________ and __________.

carbon dioxide; water

Gastric secretion begins during the __________ phase and ends during the __________ phase.

cephalic; intestinal

The network of nerves that regulate digestive motility, secretion, and blood flow is called the __________ system.

enteric nervous

As long as there is chyme in the duodenum, it will continue to stimulate gastric secretion.

false

The carbonic acid ion is joined to a hydrogen ion by the enzyme carbonic anhydrase.

false

Which of the following is a feature that the stomach and the small intestine have in common?

goblet cells

Secretin is released from the duodenum in response to _________.

hydrochloric acid in chyme

Hydrochloric acid is formed when __________.

hydrogen ions and chloride ions join in the duct of the gastric gland

How often can a sucrase molecule be used to hydrolyze sucrose?

many times

The peristaltic movement of colonic contents triggered by the gastrocolic reflex approximately 1-3 times per day is called __________.

mass movement

Defecation is stimulated by __________ and __________ reflexes.

parasympathetic; local

Stimulation from the __________ nervous system via the __________ nerve causes the secretion of HCl in the stomach.

parasympathetic; vagus

Which of the following enzymes is produced by the stomach?

pepsin

Which of the following does not stimulate the secretion of HCl in the stomach?

secretin

Defecation reflexes are stimulated by the presence of feces in the rectum.

true