Intro to Gastro

Question 1

What are the 2 general categories of the GI system?

Answer 1

hollow & solid organs

Question 2

What are the hollow organs of the GI system?

Answer 2

mouth
esophagus
stomach
SI
LI w/ rectum
anus

Question 3

What are the solid organs of the GI system?

Answer 3

salivary glands
liver
pancreas
gallbladder

Question 4

What are the 5 tastes of the tongue?

Answer 4

sweet
sour
salty
bitter
umami (savory)

Question 5

What amino acid does umami respond to?

Answer 5

glutamate

Question 6

What makes up saliva? How much is produced each day?

Answer 6

1.5 L produced each day
salivary amylase
salivary lipase
mucus (to lubricate the food)
lysozyme to kill the bacteria

Question 7

What is another name for salivary amylase?

Answer 7

ptyalin

Question 8

Swallowing has 2 phases. What are they? What controls each phase?

Answer 8

oropharyngeal phase: voluntary control

esophageal phase: autonomic control

Question 9

How long is the esophagus tube?

Answer 9

8-12 inches

Question 10

What 2 general things happen in the esophagus?

Answer 10

peristalsis: primary (initial response to food), secondary, & tertiary (makes sure that things are going in the right direction)
muscle contraction

Question 11

What ends the esophagus? …something that contributes to heartburn…

Answer 11

the lower esophageal sphincter
thought that this is what prevents heartburn when it is tightly contracted…
muscles & flesh surrounding the LES also help prevent heartburn…why obesity is associated with heartburn

Question 12

What controls entry & exit to the stomach?

Answer 12

lower esophageal sphincter (entry to the stomach)
pyloric sphincter (exit to the stomach)

Question 13

How much can the stomach hold?

Answer 13

4 cups or a treinta size Starbucks drink

Question 14

What substances are secreted in the stomach?

Answer 14

HCl
enzymes (protease, lipase)
mucus
gastrin
intrinsic factor (vitamin B12)

Question 15

What are 2 weird functions of the stomach?

Answer 15

assists in calcium absorption

makes dietary minerals soluble for absorption

Question 16

What are the 3 phases of gastric acid secretion?

Answer 16

Cephalic Phase
Gastric Phase
Intestinal Phase

Question 17

What happens in the cephalic phase of gastric acid secretion?

Answer 17

Pepsin & HCl secreted by the sense of food…

Question 18

What happens in the gastric phase of gastric acid secretion?

Answer 18

Nutrients such as AA stimulate the G cells in the stomach to produce gastrin.
Distension of the stomach also stimulates the G cells in the stomach to produce gastrin.
The release of gastrin stimulates the parietal cells to secrete HCl.
This acid slows bacterial growth which prevents enteric infections & Small intestinal Bacterial Overgrowth

Question 19

What is the approximate pH of the stomach?

Answer 19

1-4

Question 20

What are 3 things that can cause an increased risk for small intestine bacterial overgrowth?

Answer 20

achlorhydria
gastrectomy
Gi disease

Question 21

What are the 3 main cells that are found in the stomach?

Answer 21

G cells secrete Gastrin
Chief cells secrete pepsinogen & gastric lipase
Parietal cells secrete acid

Question 22

Where is chyme formed?

Answer 22

in the stomach

Question 23

Are a lot of nutrients absorbed in the stomach?

Answer 23

NO

Question 24

What protects the stomach from the digestive process?

Answer 24

the mucosa

Question 25

What are 2 things that increase the transit time thru the stomach?

Answer 25

solid meal | higher fat content

Question 26

How long does it take a liquid meal to exit?

Answer 26

1-2 hours

Question 27

How long does it take a solid meal to exit?

Answer 27

2-3 hours

Question 28

What happens in the intestinal phase of gastric acid secretion?

Answer 28

Chyme causes the duodenum to release CCK & Secretin. | These stimulate the pancreas & gallbladder to release bile, bicarb, enzymes

Question 29

Where does most digestion & absorption happen? How long is this portion of the GI tract?

Answer 29

SI | 5-7 meters

Question 30

What are the 3 parts of the SI & how long are each of them?

Answer 30

duodenum (.5 meters) jejunum (2-3 meters) ileum (3-4 meters)

Question 31

When stuff is absorbed by the SI walls...where does it go?

Answer 31

If water soluble-->blood | If fat soluble-->lymph

Question 32

How long is the LI? What is absent here? What happens here?

Answer 32

3-4 feet villi & enzymes are absent not much digestion absorption of water, minerals, vitamins happens here... bacteria break down fiber & produce Vitamin K here feces are prepared

Question 33

What is the gastrocolic reflex? What does the patient feel? What disease may this explain? What mediates this reflex?

Answer 33

increase in the motility of the colon in response to a stretch in the stomach patient feels the urge to defecate after a meal could explain irritable bowel syndrome Mediators: Serotonin, Neurotensin, CCK, gastrin

Question 34

Where is stool stored for elimination?

Answer 34

the rectum

Question 35

What are the 4 basic mechanisms for nutrient absorption?

Answer 35

passive, active, megacytosis, pinocytosis

Question 36

What is one thing that can be absorbed by the gastric epithelium?

Answer 36

ALCOHOL