Digestion and Metabolism: Organs from stomach to duodenum

Question 1

What causes PANS stimulation of the vagus nerve?

Answer 1

Sight, smell, taste, and even thoughts of food can

Question 2

What does stimulation of the vagus nerve cause?

Answer 2

innervation of the stomach cells to release mucus, HCl, pepsinogen, ghrelin, and gastrin

Question 3

When does the gastric phase begin?

Answer 3

At the arrival of food in the stomach

Question 4

What happens during the gastric phase?

Answer 4

Stretch receptors activation enhance gastrin secretions, and gastrin is released into the bloodstream

Question 5

What happens when gastrin is released into the bloodstream

Answer 5

Protein digestion, powerful contractions called mixing waves, and stimulates gastric motility

Question 6

What does Gastric Lipase do?

Answer 6

digests fat

Question 7

What is the function of Intrinsic factor?

Answer 7

vitamin B12 absrorption

Question 8

What is the function of HCl

Answer 8

Creates an acidic environment that is necessary for the cells that secrete pepsinogen, kills most microorgansims ingested, denatures proteins, inactivates most food and salivary enzymes, and helps break down plant cell walls.

Question 9

If the volume of food in the stomach increases, what else increases?

Answer 9

The activity of stretch receptors which increases intragastric pressure, which increases gastric emptying

Question 10

How does osmotic pressure affect gastric emptying?

Answer 10

The greater the osmolarity = the less gastric emptying as stomach contents are diluted.

Question 11

How does nutrient density affect gastric emptying?

Answer 11

The greater nutrient density = less gastric emptying.
For carbs, CHO effect is exterted via duodenal osmoreceptors
For Fats & Proteins, CCK

Question 12

How does particle size affect gastric emptying?

Answer 12

The greater the particle size, the lesser gastric emptying.

Question 13

What is the sieving mechanism?

Answer 13

heavier particles collecting in the lower part of the stomach

Question 14

How does viscosity affect gastric emptying?

Answer 14

Soluble fiber needs more water to be drawn in which activates appetite suppresants.

Question 15

What are insoluble fibers?

Answer 15

Fibers that swell in water found in outer skin of plants and are the main component of plant cell walls and cereal grains

Question 16

What are soluble fibers?

Answer 16

Fibers that thicken in water that are found in fleshy part of fruits and endosperm of grain, legumes, nuts and seeds.

Question 17

How do insoluble fibers treat constipation?

Answer 17

Increases stool bulk and reduce transit time by promoting movement of material through colon

Question 18

Where are short chain fatty acids produced and why aare they important?

Answer 18

Produced in the colon by bacterial fermentation of dietary fiber. It also dilutes carcinogens reducing the risk of colon cancer

Question 19

How do soluble fibers work in the digestive system?

Answer 19

They increase viscosity of stomach contents, bind to bile and reduces the reabsorption which reduces circulating cholesterol.

Question 20

What is the function of vomiting?

Answer 20

Reflex to remove toxins/poisons from the upper GI tract.

Question 21

How does vomiting work?

Answer 21

Sensations of irritation of the upper GI tract relaxes both pyloric and LES sphincters and peristaltic was discharge duodenal contents into stomach and then eventually out of mouth.

Question 22

What are Gastric Ulcers?

Answer 22

Damage of the lining of the digestive tract from stomach acid

Question 23

What causes ulcers and how are they treated?

Answer 23

NSAIDs, Helicobacter pylori, cause ulcer and are treated by antibiotics.

Question 24

When does the intestinal phase begin and what is its function?

Answer 24

When chyme enters the duodenum; It controls emptying and secretions of the digestive tract

Question 25

What does distention of the duodenum cause?

Answer 25

Inhibition of gastrin production and gastric contractions.
Stimulates contraction of pyloric sphincter to reduce further discharge of chyme

Question 26

What is secreted during the intestinal phase?

Answer 26

Alkaline mucus, Cholecystokinin (CCK), Gastric inhibitory peptide (GIP), Secretin

Question 27

What is alkaline mucus triggered by?

Answer 27

Vagal stimulation

Question 28

What is the trigger and function of Cholecystokinin (CCK)?

Answer 28

Triggered by proteins and fats in chyme;
Constricts the pyloric sphincter
Stimulates pancreatic enzyme secretion
Increases bile synthesis in the liver
Stimulates gallbladder contraction to release bile

Question 29

What is the trigger and function of Gastric inhibitory peptide?

Answer 29

Triggered by carbohydrates in chyme;
Stimulates release of insulin from pancreas in a glucose dependent manner
promotes growth and survival of pancreatic beta cell
stimulates adipogenesis

Question 30

What is the trigger and function of Secretin?

Answer 30

Triggered by decreased pH (acidity);
Stimulates pancreatic buffers
protects duodenum from acidic chyme
Increases mucus secretion in duodenum
Neutralizes pH in duodenum by optimizing functionality of pancreatic amylase and pancreatic lipase.

Question 31

What organs comprise the small intestine and what do they do?

Answer 31

Duodenum, ileum, and jejunum; they control secretions, digestion and absorption

Question 32

What is the role of the large intestine?

Answer 32

Water absorption, feces formation and expulsion