Lecture 47- Digestive System Part 2

Question 1

What does the gastric phase begin with?

Answer 1

The arrival of food in the stomach

Question 2

The activation of what type of receptors enhance gastrin sections from the cephalic phase?

Answer 2

Stretch receptors

Question 3

What three things happen when gastrin is released into the bloodstream?

Answer 3

1. Protein digestion
2. Powerful contractions (mixing waves)
3. Stimulation of gastric motility

Question 4

What is the role of intrinsic factor in the gastric phase of digestion?

Answer 4

Intrinsic factor is a glycoprotein secreted in the stomach that facilitates the absorption of vitamin B12 in the small intestine.

Question 5

What is the role of gastric lipase?

Answer 5

Digests fat

Question 6

How is pepsin increased in order to break down proteins?

Answer 6

Pepsinogen is converted into pepsin due to acidic environment

Question 7

What type of environment is essential for the function of cells that secrete pepsinogen?

Answer 7

Acidic environment

Question 8

What are the five main roles of HCl function?

Answer 8

1. Acidic environment to secrete pepsinogen
2. Acidic environment to kill microorganisms
3. Denatures proteins
4. Inactivates most of the enzymes in food
5. Helps break down plant cell walls/connective tissues in meat

Question 9

What 5 main factors determine gastric emptying?

Answer 9

1. Volume
2. Osmotic pressure
3. Nutrient density
4. Particle size
5. Viscosity

Question 10

How does an increase in volume affect the rate of gastric emptying?

How does this occur?

Answer 10

Increases rate

Increased volume=increased activity of stretch receptors=increase intragastric pressure=increased rate

Question 11

How does an increase in osmolarity affect the rate of gastric emptying?

How does this occur?

Answer 11

Decreases rate

When the stomach is more salty in needs time to dilute it first which decreases the rate

Question 12

How does an increase in nutrient density affect the rate of gastric emptying?

How does this occur?

Answer 12

Decreases rate

Can be done with carbs, fats, proteins. Needs more fluid to offset nutrients which takes more time and decreases rate

Question 13

How does an increase in particle size affect the rate of gastric emptying?

How does this occur?

Answer 13

Decreases rate

Have to sieve through large/small particles and the larger particles collect at lower part of stomach

Question 14

How does an increase in viscosity affect the rate of gastric emptying?

How does this occur?

Answer 14

Decreases rate

Soluble fiber requires more water to be drawn in and activates appetite suppressants

Question 15

What is the only determinant of gastric emptying that will increase the rate, proportional to increasing the factor?

Answer 15

Volume

Question 16

How does insoluble fiber water react in water?

Answer 16

Swells

Question 17

How does soluble fiber water react in water?

Answer 17

Thickens

Question 18

What part of the plant is insoluble fiber found in?

Answer 18

Skin

Question 19

What part of the plant is soluble fiber found in?

Answer 19

Flesh

Question 20

How does insoluble fibers treat constipation

Answer 20

Insoluble fibers treat constipation by adding bulk to stool, making it softer and easier to pass, and by stimulating the muscles in the intestines to move waste along more efficiently

Question 21

How does insoluble fibers reduce the risk for colon cancer?

Answer 21

Bacterial fermentation of dietary fiber dilutes carcinogens for cancer

Question 22

How does soluble fibers treat constipation

Answer 22

Increases water due to more viscosity which will make the stool softer

Question 23

How does soluble fibers reduce cholesterol levels?

Answer 23

Binds bile which reduces the reabsorption of bile acids

Question 24

How does soluble fibers help diabetics?

Answer 24

Viscosity entraps sugars which slows glucose absorption/lowers spikes in glucose levels

Question 25

How does vomiting reflex work?

Answer 25

-Pyloric sphincter relaxes -Peristaltic waves discharge small intestine contents to stomach -Gastroesophageal sphincter relaxes -Stomach contents through esophagus, pharynx, and mouth

Question 26

What are the six consequences of habitual purging?

Answer 26

1. Esophagus damage 2. Scar tissue formation 3. Affects peristalsis 4. Tooth decay 5. Cardiac irregularities 6. Death

Question 27

How does gastric ulcers occur?

Answer 27

When stomach acid damages the lining of the digestive tract

Question 28

What does the intestinal phase begin with?

Answer 28

Begins when chyme first enters the duodenum

Question 29

What is the primary role of the intestinal phase?

Answer 29

Controls emptying and secretions in the GI tract

Question 30

What three things does the distension (stretching) of the duodenum do?

Answer 30

1. Inhibits gastrin production 2. Inhibits gastric contractions 3. Stimulates the contraction of the pyloric sphincter which prevents further discharge of chyme

Question 31

What are the four secretions of the intestinal phase?

Answer 31

1. Alkaline mucus 2. CCK- Cholecystokinin 3. GIP- Gastric inhibitory peptide 4. Secretin

Question 32

How does CCK affect the pyloric sphincter? What does this do to gastric emptying and satiety?

Answer 32

-Constricts the pyloric sphincter -Inhibits gastric emptying -Triggers satiety by inhibiting food intake

Question 33

CCK ______ pancreatic enzyme secretion

Answer 33

Stimulates

Question 34

CCK _______ bile synthesis in the liver

Answer 34

Increases

Question 35

CCK ________ gallbladder contraction to release bile

Answer 35

Stimulates

Question 36

What does GIP stimulate the release of? What needs to be dependent for this to happen?

Answer 36

Insulin Glucose-dependent

Question 37

What does secretin stimulate the release of? What is their function?

Answer 37

Pancreatic buffers Protects the duodenum from acidic chyme

Question 38

Secretin _________ mucus secretion in the duodenum

Answer 38

Increases

Question 39

Secretin neutralizes the pH in the duodenum by optimizing the function of what two pancreatic enzymes?

Answer 39

Lipase and amylase

Question 40

In the small intestine, what is released if the pH is low?

Answer 40

Secretin

Question 41

In the small intestine, what is released if there is an increased amount of carbohydrates?

Answer 41

GIP

Question 42

In the small intestine, what is released if there is an increased amount of lipids/proteins?

Answer 42

CCK

Question 43

What do GIP, CCK, and secretin all have negative inhibition on?

Answer 43

Gastric secretions in the small intestine

Question 44

What are the two main inhibition processes of GIP on gastric secretion?

Answer 44

1. Insulin release 2. Increase of fat synthesis and storage

Question 45

What are the four organs CCK has an effect on during gastric secretion inhbition?

Answer 45

Liver, pancreas, pyloric sphincter, and gallbladder

Question 46

What is the function at the liver, gallbladder, pancreas, and pyloric sphincter during CCK inhibition of gastric secretion?

Answer 46

Liver- increase bile synthesis Gallbladder- release bile Pancreas- digestive enzymes Pyloric Sphincter- constriction

Question 47

What organ does secretin affect/what is the function?

Answer 47

Pancreas- mixture of bicarbonate and water to increase pH so digestive enzymes can function

Question 48

What is the function of pancreatic alpha amylase?

Answer 48

Breaks down carbs and starches

Question 49

What is the function of protease?

Answer 49

Breaks down proteins into amino acids

Question 50

What is the function of pancreatic lipase?

Answer 50

Breaks down fats in the pancreas

Question 51

What is the function of nucleases?

Answer 51

Break down RNA or DNA

Question 52

What are the four pancreatic enzymes?

Answer 52

1. Pancreatic alpha amylase 2. Protease 3. Pancreatic lipase 4. Nucleases