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NBCE Part 1 > Gastrointestinal Review > Flashcards

Flashcards in Gastrointestinal Review Deck (21)
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1
Q

Describe the functions of the GI tract

A

Digestion
absorption
Excretion
endocrine

2
Q

Describe the mouths function

A

Mastication along with salivary amylase assists in breakdown of CARBS and STARCHES into maltose

3
Q

Describe the stomach cells

A

Mucosal (neck) - secretes mucus and gastrin, G cells produce gastrin which stimulates gastric secretions

Chief Cells - produce pepsinogen, HCL activates pepsinogen to active form pepsin (aids in protein digestion)

Parietal - secretes HCL and intrnisic factor, HCL destroys many bacteria, intrinsic factor is necessary for absorption of Vit B12 in terminal

Mast - secrete histamine

4
Q

Describe the function of chyme in the SI

A

Presences stimulates the release of secretin from S-cells found in the duodenum

Secretin stimulates pancreatic acinar cells to release bicarbonate and water and decreases gastric activity

Bicarbonate-rich mucus is also secreted by Brunner’s glands neutralizing the gastric acid and makes the pH alkaline

5
Q

Describe CCK

A

Stimulated by fat in the duodenum
released by I-cells
causes sphincter of Oddi to relax
causing bile to be excreted into duodenum
Also stims the pancreas to secrete enzymes which aid in of fat, starches, and protein

Pancreatic amylase completes breakdown of maltose

6
Q

Describe the breakdown of sugars in the SI

A

Maltase —> maltose —> two molecules of glucose

Lactase –> lactose —> glucose and galactose

Sucrase –> sucrose –> glucose and fructose

7
Q

Describe the exocrine function of the pancreas

A

Makes up the bulk of the pancreas
Tyrpisogen is activated by enterokinase into trypsin
Pancreatic amylase aids in digestion of starch to produce maltose
Lipase breaks downs fat into fatty acids and glycerol

8
Q

Describe the endocrine function of the pancreas

A

Glucagon (alpha =20%)
Insulin (beta = 70% of islet cells)
Somatostatin (delta =10%)

9
Q

Describe the large intestine

A

Absorbs most of the water
Bacteria found in LI produce vitamin K
Contains numerous goblet cells that secrete mucus

10
Q

Describe vitamin and mineral absorption

A

Fat soluble: DAKE
Water soluble: B, C and folic acid (B12 exception) enter enterocytes by secondary active transport mechanisms using Na - amino acid co-transporters

Folic acid and Iron are absorbed in the Jejunum:

  • Iron combines with apotransferrin in the blood to form transferrin
  • transferiin carries the iron in the blood to cells in the live,r spleen, and bone marro
  • iron is then bound to apoferritin to form ferritin
11
Q

What is the role of the liver

A

Carb metabolism: glycogenesis, glycogenolysis, gluconeogenesis
Protein metabolism
Lipid metabolism
Stores: glycogen and vitamins A, D, and B12
Detoxes
Conjugates bilirubin
Makes steroids. clotting factors
Makes RBC in fetuses
involved in immunity through Kupffer cells

12
Q

Describe bilirubin

A

Byproduct of RBC breakdown in the spleen

RBC > 120 days broken down into heme and globin

13
Q

Describe the role of the gallbladder

A

Stores (50cc) and concentrates bile
Excretes bile in response to fat in the duodenum
Stimulated by CCK

14
Q

Describe gastrin

A

G cells
Stimulates HCL secretion from parietal cells
stimulates gastric motility

15
Q

Describe somatostatin

A

D cells in stomach and delta islet cells in pancreas

decreases pancreatic secretion

16
Q

Describe gastric inhibitory peptide

A

K cells

decreases gastric acid secretion

17
Q

Describe CCK

A

I cells
stimulates contraction of the gallbladder
relaxes sphincter of oddi and the lower esophageal sphincter (cardiac)

18
Q

Describe secretin

A

S cells in the intestinal crypts of lieberkuhn
stimulates the release of bicarbonate from pancreas
decreases gastric acid secretion

19
Q

describe glucagon-like peptide

A

K cells in duodenum and jejunum

inhibits gastric emptying

20
Q

Describe ghrelin

A

P cells in stomach

increased before meals and decreased after

21
Q

describe motilin

A

M cells in duodenum
controls the cyclical movement of gut
increased in fasting state