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Flashcards in lecture 10: pancreas + salivary glands Deck (30):
1

Describe two types of glands

Exocrine: develop from surface epithelium + retain contact with it
Endocrine: lose contact with surface epithelium

2

Name classes of exocrine glands

Simple = one straight, unbranched duct
compound = 2+ branches of ducts

3

What is the function of the three major places of glands in oral cavity?

production of saliva

4

what does saliva contain?

hypotonic + slightly alkaline
water
electrolytes: SODIUM, POTASSIUM, CHLORIDE, bicarb
proteins: amylase, lingual lipase, lysozyme, IgA, mucins, histidine-rich peptides, EGF, nerve growth factor

5

what do salivary duct cells do?

protein/mucus production
Na re-absorption
K, bicarbonate secretion

6

what kinds of proteins do salivary acini produce?

amylase
antibacterial factors

7

what kind of salivary glands are the sublingual, submandibular and parotid?

sublingual = seromucous, mucous
subamndibular = mostly serous, seromucous, mucous
parotid = serous

8

how does osmolality change from acinus to interlobular duct?

decreases

9

what are net effects on electrolyte transport in salivary ducts?

out of basolateral = Na and Cl
out to duct lumen = K and bicarbonate

10

what does ACh control?

salivary fluid and protein secretion

11

what are the functional parts of the pancreas?

exocrine = acini + ducts = digestion = majority
endocrine = islets of Langerhans = hormones = minor

12

what are the functions of the exocrine pancreas?

synthesis and secretion of digestive enzymes: proteases, lipases, amylase, nucleases
secretion of bicarbonate and water

13

what are the functions of the endocrine pancreas?

synthesis and secretion of hormones: insulin, glucagon, somatostatin, others (ghrelin, VIP)

14

what do cells in pancreatic acini do?

duct epithelial cells = secrete bicarbonate and water
acinar cells = make digestive enzymes = proteases, lipases, amylase

15

what kind of cells are mainly found in the islets of langerhans?

B cells, insulin

16

what's the composition of pancreatic juice?

water
electrolytes: Na, K, CHLORIDE, BICARBONATE
proteins: PROTEASES, amylase, lipases, nucleases, protease inhibitors

17

what are the net effects of electrolyte transport in duct epithelial cells?

out to basolateral surface: acid
out to apical side: bicarbonate

18

Describe what happens when pH drops in the duodenum after acid comes through pyloric sphincter.

1) the low pH and fatty acids stimulate S cells to secrete secretin
2) secretin stimulates duct cells in the pancreas to release bicarbonate
3) ACh and CCK potentiate bicarbonate response to secretin
4) bicarbonate travels out through sphincter of Oddi to counteract drop in pH

19

What kind of the proteins are most of the pancreatic secretory proteins?

proteases

20

why are proteases and lipases secreted as inactive from the pancreas?

they are secreted as inactive pro-forms (zymogens) to protect the pancreas from self-digestion

21

what do enterocytes produce that help with zymogen activation in intestinal lumen?

enterocytes in lumen of duodenum produce "enterokinase", a peptidase

22

what does enterokinase do?

enterokinase cleaves (thereby activating) trypsinogen into trypsin in the lumen of the duodenum

23

what does trypsin do?

trypsin activates other proteolytic enzymes (zymogens) coming in from the pancreas

24

what effect does CCK have on pancreatic enzyme secretion?

CCK stimulates pancreatic enzyme secretion
indirect stimulation via vagovagal reflexes

25

what neurotransmitters are involved in vagal stimulation of pancreatic acini for enzyme release?

ACh
GRP
VIP

26

what second messengers are associated with stimulation of pancreatic acinar cells at the basolateral surface?

VIP = cAMP

ACh, GRP, CCK = calcium

27

what does monitor peptide do?

secreted by acinar cells along with zymogens to inhibit prematurely activated trypsin

28

Describe the feedback regulation of CCK production in the fasting vs. fed states

Fasting state:
monitor peptide, CCK-releasing factor will degrade trypsin - no CCK released
Fed state:
food proteins regulate degradation of CCK-releasing factors by competing with trypsin activity; CCK-RF remains intact and CCK gets released

29

What cells secrete bicarbonate/water in pancreas? What are the regulators?

ducts release bicarbonate, water
regulators = secretin, ACh, CCK

30

what cells secrete digestive enzymes in the pancreas? what are the regulators?

acini release digestive enzymes
regulators = CCK, ACh, GRP, VIP, SP