Digestive System
Where is sucrase found in the human body?
On the microvilli of the small intestine
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
Blood sugar refers to circulating levels of __________ in the blood.
gluclose
Which of the following is a feature that the stomach and the small intestine have in common?
goblet cells
Cholecystokinin, which is produced in the small intestine, inhibits gastric secretions in the stomach.
true
Defecation reflexes are stimulated by the presence of feces in the rectum.
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
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
Chemical digestion is a series of chemical reactions that break large chunks of food into proteins, carbohydrates, and fats.
false
The carbonic acid ion is joined to a hydrogen ion by the enzyme carbonic anhydrase.
false
The medulla oblongata controls gastric secretion by utilizing the parasympathetic branch of the nervous system and the endocrine system.
false
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
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
