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Endocrinology - Kalnins 2017 > Pancreas / Diabetes > Flashcards

Flashcards in Pancreas / Diabetes Deck (54)
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1

these endocrine cells of the pancreas secrete insulin, glucagon and somatostatin directly into the blood

islet of Langerhans

1-2% mass of pancreas

2

these exocrine cells of the pancrease secrete digestive enzymes into tiny ducts while also possessing some bicarbonate-secreting cells

pancreatic acinar cells

3

what is the largest duct of the pancreas?

pancreatic duct

- joins the common bile duct (LV/GB) to enter the duodenum at the hepatopancreatic ampulla (ampulla of Vater)

4

what smooth muscle regulates the release of secretions from the pancreatic duct?

hepatopancreatic sphincter (sphincter of Oddi)

5

how much pancreatic juice is produced daily?

1200-1500 mL

water, some salt
sodium bicarbonate (alkalinizes pancreatic juice & later chyme 7.1-8.2)
enzymes

6

what zymogens are contained within the pancreatic secretions?

- pancreatic amylase
- trypsin, chymotrypsin, carboxypeptidase, elastase
- pancreatic lipase
- ribonuclease, deoxyribonuclease

7

what aspect of the pancreatic secretions stops the action of pepsin in the duodenum?

sodium bicarbonate (pH 7.1-8.2)

8

what 3 things stimulate exocrine secretion from the pancreas?

- PNS (gastric phase of digestion - vagas n.)

Mucus secretes these in response to chyme entering duodenum:
- Secretin (goes through portal blood to pancreas increasing bicarb)
- Cholecystokinin (CCK) (enters portal blood to pancreas stimulating digestive enzyme secretion)

9

these endocrine pancreas cells produce GLUCAGON, active in the liver and kidneys to promote glycogenolysis and gluconeogenesis - making up approx 15-20% of the pancreas - what are they?

Alpha cells

secretions
stimulated by: hypoglycemia, epi, ACh, CCK
inhibited by: somatostatin, insulin, PPARgamma

10

these endocrine pancreas cells produce INSULIN, C-PEPTIDE & AMYLIN, making up 65-80% of the pancreas - which cell type is this?

Beta cells

BETA CELLS have GLUT2 TRANSPORTERS*
most other cells have GLUT4

insulin:amylin = 100:1

11

what are the actions of amylin from the beta cell of the pancreas??

slows gastric emptying
promotes satiety
prevents post-prandial spikes in blood glucose

12

these endocrine cells produce somatostatin which inhibits alpha and beta cells in the pancreas, decreases stomach acid, suppresses other GI hormones, inhibits GH, suppresses exocrine pancreas activity too! It essentially puts the brakes on everything. What cell makes this emergency brake?

Delta cells (3-10% of cells)

13

these endocrine cells produce pancreatic polypeptide - which helps to regulate pancreatic secretions, influence hepatic glygocen levels and GI secretions - what cell type is this?

PP cells (3-5%)

14

these endocrine cells produce ghrelin the hunger hormone! which is secreted when the stomach is empty and acts on the brain to increase hunger.. Which cell type make this one?

Epsilon cells (<1%)

15

this hormone, inhibits secretory activity in the stomach, potentiates secretin, increases enzyme-rich pancreatic juice, stimulates GB contraction and relaxes the sphincter of oddy to allow entry of bile and pancreatic juice into the duodenum

Cholecystokinin (CCK)

16

this hormone inhibits HCl production (minor) but mostly stimulates the release of insulin and therefore is a target for diabetic pharmacologic therapy

Gastric Inhibitory Peptide (GIP)

made in duodenal mucosa

17

this hormone increases HCl secretion, stimulats gastric emptying (minor). It stimulates contraction fthe intestinal muscle, relaxes the ileocecal valve and stimulates mass movements

Gastrin

18

this hormone activates parietal cells to release HCl

histamine

stomach mucosa produces this

19

this hormone stimulates the migrating motor complex

Motilin

20

this hormone causes contraction of stomach muscle

serotonin

21

this hormone inhibits everything - the big brake! all things digestive.. what is it?

somatostatin

22

this peptide hormone regulates metabolism of carbohydrates and lipid by promoting absorption of glucose from the blood to the myocytes and adipose

insulin

the hormone of anabolism
- increased glycogen synth (LV and mm), FA synthesis and storage (adipose), AA uptake
- decrease -lysis of protein, lipid and glucose
- decrease autophagy
- increase HCl in stomach

23

insulin consists of 2 polypeptide chains, A & B, what bond links these chains?

disulfide bond

(the same bond responsible for curly hair!)

24

insulin is first synthesized as a single polypeptide called

preproinsulin

this is what exits the ribosome, then signal peptide binds to lead preproinsulin to the rough ER, where it enters and becomes proinsulin

25

Where is proinsulin cleaved by endopeptidases into C-peptide and insulin (A=B chains, disulfide)

trans-Golgi network (TGN)

26

what is a better measure of insulin levels?

c-peptide

- insulin and c-peptide are released from pancreas - DM2 pts secrete increased proinsulin, indistinguishable from insulin - c-peptide is therefore a better indicator

27

What are the two phases of insulin release?

- rapid phase in response to dietary glucose

- sustained, slow release independent of glucose (GIP, GLP-1)

28

aside from glucose, the main promoter of insulin - what else stimulates it's release (4)?

- some AAs - leucine, arginine
- acetylcholine (vagus n.)
- cholescystokinin (CCK)
- gastrointestinal incretins (GLP-1, GIP)

29

insulin can be an effective way to treat what?

hyperkalemia
due to it's ability to drive K back into the cell.

30

what enzyme, found in the liver and kidneys, deactivates insulin?

insulin-degrading enzyme

4-6 min halflife
degraded in approx 1 hr post-secretion