exam 3 phy 503

Question 1

TRUE/FALSE: Patients with a lactase deficiency can digest milk products that contain lactose (milk sugar)?

Answer 1

False: Patients with a lactase deficiency cannot digest milk products that contain milk products (milk sugar). Blood glucose levels do not increase because lactose is not digested to glucose and galactose in these patients.

Question 2

Duodenocolic Refelx

Answer 2

Reflex begins in the the duodenum and ends in the colon. When the duodenum is distended (stretches), nervous signals are transmitted to the colon which stimulates mass movements.

Question 3

Enterogastric Reflex

Answer 3

occurs when signals originating in the intestines inhibit gastric motility and gastric secretion.

Question 4

Intestino-intestinal Reflex

Answer 4

occurs when overdistention or injury to bowel segment signals and the bowel to relax.

Question 5

Retrosphincteric Reflex

Answer 5

initated when feces enters the rectum and stimulates the urge to defecate.

Question 6

Vitamin B12

Answer 6

absorbed in the ileum; this absorption requires intrinsic factor which is a glycoprotein secreted by parietal cells in the stomach.

Question 7

Atrophic Gastritis

Answer 7

a type of autoimmune gastritis that is mainly confined to the acid-secreting corpus mucosa. The gastritis is diffuse and severe atrophy eventually develops. IIeal resection is likely to cause diarrhea but not constipation.

Question 8

Gastric Ulcer

Answer 8

A stomach ulcer occurs when stomach acid eats through your protective stomach lining, producing an open sore

Question 9

GERD

Answer 9

caused by gastric acid and bile reflex into the esophagus, musocsal damage and epithelial cell transformation lead to Barret esophagus.

Question 10

What is the highest concentration in saliva under basal conditions?

Answer 10

Bicarbonate

Question 11

The presence of fat, carbohydrates, or protein in the duodenum stimulates the release of which hormone from the duodenal mucosa?

Answer 11

GLIP: Glucose-dependent insulin-tropic peptide

GLIP is the only gastrointestinal hormone released by all 3 major foodstuff (fats, proteins, and carbohydrates).

Question 12

TRUE/FALSE: GLIP is a strong stimulator of insulin release and is responsible for the observation that an oral glucose load releases more insulin and is metabolized more rapidly than equal amount of glucose administrated intravenously.

Answer 12

True

Question 13

TRUE/FALSE: CCK AND VIP stimulates the release of insulin?

Answer 13

False: Neither CCK or VIP stimulate the release of insulin.

Question 14

Digestion of which of the following is impaired to the greatest extent in patients with achlorhydria?

A) Carbohydrates
B) Fat
C) Protein

Answer 14

C: Protein

Achlorhydria means that the stomach fails to secrete HCL (hydrochloric acid). This condition is diagnosed when the pH of the gastric secretions fails to decrease below 4 after stimulation by pentagastrin. When acid is not secreted, pepsin also isn’t secreted. Because pepsin requires an acid medium for activity, protein digestion is impaired.

Question 15

Achalasia

Answer 15

a condition in in which LES (lower esophageal sphincter) fails to relax during swallowing. As a result, food swallowed into the esophagus fails to pass from the esophagus into the stomach. Indication on a chart will show a high pressure that fails to decrease after swallowing.

Question 16

The proenzyme pepsinogen is secreted mainly from ?

Answer 16

Gastric Glands of the stomach

-Pepsinogen is the precursor of the enzyme pepsin. Pepsin is secreted from the peptic or Cheif cells) of the gastric gland.

Question 17

What hormone released by the presence of fat and protein in the small intestine and has a major effect in decreasing gastric emptying is called?

Answer 17

CCK
-its the only gastrointestinal hormone that inhibits gastric emptying under physiological conditions.

Question 18

Compared with the plasma, saliva has the highest relative concentration of which ion under basal conditions?

Answer 18

Potassium

Question 19

TRUE/FALSE: Sodium and Chloride ions have low concentrations under basal conditions?

Answer 19

TRUE

Question 20

Which of the following can inhibit gastric acid secretion?

A) Somatostatin
B) Secretin
C) GLIP
D) Enterogastrones
E) Nervous Reflexes
(F) All the above

Answer 20

F) all the above

Somatostatin, Secretin, GLIP, Enterogastrones, Nervous Reflexes

Question 21

The gastrointestinal hormones have physiological effects that can e elicited at normal concentrations, as well as pharmacological effects that require higher than normal concentrations. What is the direct physiological effect of the various hormones on gastric acid secretion?

Answer 21

Gastrin: Stimulate
Secretin: Inhibit
CCK: No effect
GLIP: Inhibit
Motilin: No effect

Question 22

The cephalic phase of gastric secretion accounts for about 30 percent of the acid response to a meal. Which of the following can completely eliminate the cephalic phase of gastric secretion?

A) Antacids (rolaids)
B) Antigastrin Antibody
C) Atropine
D)Histamine H2 blocker
E) Vagotomy
F) Sympathectomy

Answer 22

E) Vagotomy

Because the cephalic phase of gastric secretion is mediated entirely by way of the vagus nerve, vagotomy can abolish the response.

Question 22

TRUE/FLASE: Antacids neutralize gastric acid and inhibit gastric secretion?

Answer 22

False
Antacids neutralize gastric acid but DO NOT inhibit gastric secretion.

Question 23

Migrating motility complexes (MMCs) occur every 90 minutes between meals and are thought to be stimulated by the gastrointestinal hormone motilin. An absence of MMCs causes an increase in?

Answer 23

Intestinal Bacterial

-MMCs are peristaltic waves of concentration that begin the stomach and slowly migrate in an aboral direction along the entire small intestine to the colon. By sweeping undigested food residue from the stomach, through the small intestine and into the Colon, MMCs function to maintain low bacterial counts in upper intestine. bacterial overgrowth syndrome can occur when the normally low bacterial colonization in the upper GI tract increases significantly.

Question 24

Gastric empyting is tightly regulated to ensure that chyme enters the duodenum at an appropriate rate. What event promotes gastric emptying under normal physiological conditions in a healthy person?

Answer 24

Tone of Orad Stomach: increases Segmentation contractions in small intestine: Decreases Tone of pyloric sphincter: Decreases Gastric emptying is accomplished by coordinated activities of the stomach, pylorus, and small intestine. Conditions that favor gastric emptying include (a) increased tone of the orad stomach, which helps to push chyme toward the pylorus.

Question 25

toxin from V.cholerae

Answer 25

The toxin from V. cholerae (cholera toxin) causes an irreversible increase in cAMP levels in the enterocytes located in the crypts of Lieberkühn of the small intestine. This increase in cAMP causes an irreversible opening of chloride channels on the luminal membrane.

Question 26

True/False: Movement of chloride ions into the gut lumen causes a secondary movement of sodium ions to maintain electrical neutrality?

Answer 26

True

Question 27

The gastrointestinal hormones have physiological effects that can be elicited at normal concentrations as well as pharmacological effects that require higher than normal concentrations. What is the physiological effect of the various hormones on gastric emptying?

Answer 27

Gastrin: none Secretin: None CCK: Decrease GLIP: None Motilin: None CCK is the only gastrointestinal hormone that inhibits gastric emptying under normal physiological conditions. CCK inhibits gastric emptying by relaxing the orad stomach, which increases its compliance.

Question 28

The function of the gastrointestinal (GI) tract can be summarized by the following mechanism(s): (A) Motility (B) Secretion (C) Digestion (D) Absorption (E) All of the above

Answer 28

E: All the above

Question 29

Which one of the following is consistent with absorption of glucose molecules across the intestinal epithelium? (A) Glucose enters the intestinal epithelial cell through glucose channels in the apical membrane and leaves the cell through the basal membrane by facilitated diffusion. (B) Glucose enters through the apical membrane by facilitated diffusion and leaves through the basal membrane by facilitated diffusion also. (C) Glucose enters the cell through the apical membrane by co-transport with Na+ and leaves the cell through the basal membrane by facilitated diffusion. (D) Glucose enters the cell through the apical membrane by facilitated diffusion and leaves the cell through the basal membrane by co-transport with Na+. (E) None of the above.

Answer 29

C): Glucose enters the cell through the apical membrane by co-transport with Na+ and leaves the cell through the basal membrane by facilitated diffusion.

Question 30

Most of the chemical digestion in the gastrointestinal (GI) tract occurs in the: (A) Mouth (B) Stomach (C) Small intestine (D) Large intestine

Answer 30

C): Small Intestine

Question 31

Most of the water and electrolytes absorbed across the walls of the gastrointestinal (GI) tract is absorbed in this region: (A) Mouth (B) Stomach (C) Small intestine (D) Large intestine

Answer 31

C): Small intestine