Saliva Secretions

Question 1

what GI components produce secretions?

Answer 1

salivary glands gastric mucosa pancreatic exocrine cells liver

Question 2

how much saliva is secreted into the mouth per day

Answer 2

1L/day

Question 3

what are the functions of saliva

Answer 3

1. mucus for lubrication 2. enzymes for initial digestion of lipids and starches 3. dilution and buffering of ingested foods

Question 4

what comprises parotid gland

Answer 4

serous glands secrete water, ions, and enzymes

Question 5

what comprises submandibular gland

Answer 5

serous and mucous glands secrete water and mucin glycoproteins

Question 6

what comprises the sublingual gland

Answer 6

serous and mucous glands (mostly mucous) secrete water and mucin glycoproteins

Question 7

what leads to the ejection of saliva into the mouth?

Answer 7

neural stimulation of myoepithelial cells present in acini and intercalated ducts

Question 8

what neural stimulation stimulates ejection of saliva?

Answer 8

predominantly parasympathetic but both SNS and PSNS

Question 9

what part of salivary gland actually makes the secretions

Answer 9

acini

Question 10

what do the intercalated and striated ducts do

Answer 10

chemically modify the electrolyte composition in response to the need at the time (rate and amount)

Question 11

what impact does SNS activation have on salivary gland blood flow?

Answer 11

causes vasoconstriction to shut down blood flow and decrease secretion

Question 12

what impact does PSNS activation have on salivary gland blood flow?

Answer 12

causes vasodilation to increase blood flow and secretion

Question 13

what occurs in high salivary demand?

Answer 13

Kallikrein is released to activate bradykinin, which causes vasodilation

Question 14

what substance is crucial in increasing secretions?

Answer 14

bradykinin (vasodilates)

Question 15

arterial blood supply to parotid gland

Answer 15

branches of external carotid artery

Question 16

arterial blood supply to submandibular gland

Answer 16

branches of facial and lingual artery

Question 17

arterial blood supply to sublingual gland

Answer 17

sublingual and submental artery

Question 18

innervation of parotid gland

Answer 18

glossopharyngeal hitches ride to V3 to otic ganglion then to parotid

Question 19

innervation of submandibular gland

Answer 19

chorda tympani

Question 20

innervation of sublingual gland

Answer 20

chorda tympani

Question 21

describe saliva composition

Answer 21

is hypotonic thanks to luminal antiports but is NOT an ultrafiltrate of blood (is formed de novo)

Question 22

what does saliva have in it

Answer 22

more K than blood more HCO3 than blood less Na than blood less Cl than blood

Question 23

how is saliva formed

Answer 23

1. formation of isotonic plasma like solution by acinar cells 2. modification of this solution by ductal cells

Question 24

how is solution modified by ductal cells?

Answer 24

the serosal Na/K ATPase creates a Na gradient where Na is low inside the cell. Na then follows its concentration gradient by being resorbed from luminal primary saliva. leads to less Na in the saliva.

Question 25

what luminal ductal transporters are in ductal cells?

Answer 25

1. Na/H antiport 2. Cl/HCO3 antiport 3. H/K antiport

Question 26

what other substances do acinar cells secrete

Answer 26

1. alpha amylase 2. lingual lipase 3. mucin glycoproteins 4. IgA 5. Kallikrein

Question 27

what does kallikrein secretion do

Answer 27

converts kininogen to bradykinin to produce vasodilation and increased salivary blood flow during periods fo increased saliva demand

Question 28

describe saliva composition during flow saliva flow rates (less than 1mL per min)

Answer 28

hypotonic to blood plasma

Question 29

describe saliva composition during high saliva flow rates (4mL/min)

Answer 29

is isotonic to blood plasma more Cl and Na present

Question 30

what is saliva compositon proportional to?

Answer 30

amount of exposure time to ductal cells more time exposed to ductal cells, more hypotonic, less time, more isotonic

Question 31

how is saliva secretion unique to the rest of GI secretions?

Answer 31

it is under sole control of ANS. no endocrine regulation. both PSNS and SNS stimulate salivary secretion.

Question 32

how does the sympathetic nervous system stimulate salivary secretion??

Answer 32

T1-T3 (mainly T2) stimulates NE release and binding to beta adrenergic receptors. this increases cAMP release to increase saliva. basically NE binding to beta adrenergic receptors increases cAMP to increase saliva

Question 33

what triggers the PSNS to increase saliva?

Answer 33

conditioning food nausea smell

Question 34

what inhibits PSNS saliva release?

Answer 34

dehydration fear sleep

Question 35

how does PSNS increase saliva release?

Answer 35

facial nerve and glossopharyngeal nerves release Ach to bind muscarinic receptors. binding of Ach increases IP3 to increase Ca to increase saliva.

Question 36

what is different between PSNS and SNS innervation of salivary glands

Answer 36

parasympathetic has singular innervation, meaning the innervation comes from the same nerve root, just has a branch to blood vessel and gland. sympathetic has dual innervation, meaning there are 2 separate innervations to the blood vessel and gland.

Question 37

what duct provides most of saliva?

Answer 37

submandibular gland at 70%

Question 38

how much saliva does the parotid gland contribute? and sublingual?

Answer 38

20% 5%

Question 39

how does PSNS innervate parotid gland

Answer 39

directly via glossopharyngeal nerve

Question 40

how does SNS innervate parotid gland

Answer 40

indirectly via superior cervical ganglion where beta adrenergic receptor NE binding increases cAMP to stimulate secretion

Question 41

how does PSNS innervate sublingual and submandibular glands

Answer 41

facial nerve via Ach and substance P secretion to increase IP3 and Ca release

Question 42

how is saliva secreted from sublingual gland?

Answer 42

mucoid saliva exits directly from 8-20 excretory Rivinus ducts

Question 43

how is saliva secreted from submandibular glands?

Answer 43

serous fluid with alpha amylase and mucus is secreted via submandibular gland to mouth