Salivary function and secretion

Question 1

What are the 3 major salivary glands?

Answer 1

Parotid
Submandibular
Sublingual

Question 2

What duct is related to the parotid gland?

Answer 2

Duct of Stensen

Question 3

Where does the duct of stensen enter the mouth?

Answer 3

opposite second maxillary molar tooth

Question 4

What is the duct of stensen otherwise known as?

Answer 4

Parotid duct

Question 5

What duct is related to the submandibular gland?

Answer 5

Duct of wharton

Question 6

What is a salivon?

Answer 6

The salivary functional unit

made up of secretory acinus and ducts

Question 7

What is the secretory acinus?

Answer 7

The secretory cells which make the saliva

Question 8

What are the major ducts sublingual glands?

Answer 8

Duct of Rivinus and common Bartholin

Question 9

What does the salivary gland consist of?

Answer 9

An external capsule
Septae separating the tissue inside the glands into lobes and lobules
Lobules consisting of salivons

Question 10

What cells surround the acini to secrete the saliva?

Answer 10

Myocontractile cells

Question 11

What does a salivon consist of?

Answer 11

Secretory acinus
Intercalated duct
Striated duct

Question 12

What is the route of fluid movement in the salivon?

Answer 12

Acinus -> Intercalated duct -> Striated duct -> Excretory duct

Question 13

What do the striated ducts unite to form?

Answer 13

Interlobular ducts

Excretory ducts

Question 14

What forms the acinus?

Answer 14

Pyramidal-shaped secretory acinar cells (the apex is directed into the lumen) - around the central lumen

Question 15

What are the two types of acinar cells?

Answer 15

serous cells

mucous cells

Question 16

Describe the serous cells

Answer 16

produce a watery solution rich in alpha amylase

contain small, dense, secretory granules

Question 17

Describe the mucous cells

Answer 17

produce a thick mucous rich solution

large, pale, secretory granules

Question 18

The order of structures in the salivon

Answer 18

contractile myoepithelial cells -> serous demilunes -> acinus (serous or mucous cells) -> intercalated duct -> striated duct -> excretory duct

Question 19

What are the two stages of saliva formation?

Answer 19

1) Primary secretion by acinar cells

2) Seocondary modification by duct cells

Question 20

What happens in the primary secretion part of saliva formation?

Answer 20

An isotonic solution compared to plasma formed due to the secretion of Na+, Cl- and H20 into the lumen from the acinar cells

Question 21

What happens in the secondary modification part of saliva formation?

Answer 21

An hypotonic solution forms compared to the plasma due to secretion of K+ and HCO3- from the duct cell to the lumen and secretion of Cl- and Na+ (NOT WATER) into the blood vessel from the duct cell

Question 22

Functions of saliva

Answer 22

lubrication 
protection 
digestion
others:
- secretions prior to vomiting 
- facilitates suckling by infants

Question 23

What is the function of lubrication used for?

Answer 23

• aids movement
• facilitates speech
• helps chewing and swallowing

Question 24

State 2 examples of why protection is important in saliva function

Answer 24

high calcium salt content helps to prevent demineralisation of tooth enamel
lysozyme attacks bacterial cell wall

Question 25

State 2 examples of why digestion function is important in saliva

Answer 25

alpha amylase breaks down carbohydrates and then continues in the stomach lingual lipase initiates fat digestion

Question 26

What acinar cells are present in the parotid gland?

Answer 26

Serous cells

Question 27

What acinar cells are present in the submandibular glands?

Answer 27

both serous cells and mucous cells

Question 28

What acinar cells are present in the sublingual glands?

Answer 28

mainly mucous cells

Question 29

As the flow rate increases, what is the effect on K+ and HCO3-?

Answer 29

HCO3- increases | K+ decreases

Question 30

What cranial nerve supplies the submandibular and sublingual glands?

Answer 30

CN VII

Question 31

What cranial nerve supplies the parotid glands

Answer 31

CN IX

Question 32

Effect of parasympathetic stimulation on saliva secretion

Answer 32

increase synthesis and secretion of alpha amylase increase fluid flow increase contraction of the myoepithelial cells increase blood flow to glands Produces watery saliva

Question 33

Which muscarinic receptors does ACh work on to cause saliva production down the parasympathetic route

Answer 33

M1 and M2

Question 34

How does ACh effect the acini cells?

Answer 34

causes an increase in calcium concentration which drives fluid secretion in a complicated manner

Question 35

Effects of sympathetic stimulation on saliva secretion

Answer 35

increase secretion of alpha amylase, K+ and HCO3- increase contraction of myoepithelial cells decrease blood flow to glands Produces mucous thick saliva

Question 36

What receptors mediate sympathetic saliva production?

Answer 36

a1-adrenoreceptors which increase [Ca2+] | b1-adrenoreceptors which increase [cAMP]

Question 37

What is the effect of calcium on the sympathetic saliva production?

Answer 37

stimulate fluid secretion

Question 38

What is the effect of cAMP on the sympathetic saliva production?

Answer 38

increases the production of protein

Question 39

Is ENaC a voltage activated Na+ channel?

Answer 39

NO

Question 40

What activates ENaC?

Answer 40

Aldosterone

Question 41

How is an increase in [Ca2+]i produced?

Answer 41

Initiated by release of Ca2+ from the ER following activation of M1 and M3 Sustained by store-operated calcium entry (SOCE)

Question 42

Which two receptors are activated by IP3

Answer 42

IP3R2 and IP3R3

Question 43

How is IP3 formed?

Answer 43

Hydrolysis of PIP2

Question 44

What causes IP3 generation?

Answer 44

Gq/11 coupling to M1 and M3 and PLCbeta3

Question 45

Where does the initial signal of Ca2+ arise in the acinar cell?

Answer 45

apical pole

Question 46

What type of messenger is IP3?

Answer 46

Secondary messenger

Question 47

What is the effect of increased [Ca2+] on IP3 receptors?

Answer 47

As the concentration increases, there is an increase in the IP3 receptor activity to a peak and then it falls

Question 48

What is the receptor on the ER responsible for Ca2+ release called?

Answer 48

Ryanodine receptor

Question 49

What initiates SOCE?

Answer 49

Any stimuli which detect a depletion of the Ca2+ ER store, e.g. - Any stimulus which generates IP3 - Pharmacological inhibition of SERCA

Question 50

What detects a decrease in Ca2+ in the ER store?

Answer 50

STIMs

Question 51

How are the ER stores refilled?

Answer 51

By SERCA

Question 52

Example of an inhibitor of SERCA

Answer 52

Thapsigargin (Tg)

Question 53

What type of STIM is in the salivary glands?

Answer 53

STIM1

Question 54

What is STIM1

Answer 54

A calcium sensing protein

Question 55

What happens to STIM1 when the ER stores are depleted?

Answer 55

undergoes a conformational change and they physically couple to the cells on the plasma membrane receptors

Question 56

Which EF hand motif binds calcium in STIM?

Answer 56

Canonical EF (cEF)

Question 57

Which EF hand motif does not bind calcium in STIM?

Answer 57

Hidden EF (hEF)

Question 58

When calcium is present, what motif binds to EF when calcium is present?

Answer 58

SAM

Question 59

What is puncta?

Answer 59

When in the absence of calcium, the STIM1 aggregates in the ER to the plasma membrane

Question 60

What are the two components of the C terminus of STIM1?

Answer 60

Coiled coil 1 (cc1) and coiled coil 2 (cc2)

Question 61

What is Orai1

Answer 61

A store operated channel

Question 62

What does the STIM1 CC2 domain present to Orai1?

Answer 62

- STIM1 Orai-activating regions (SOAR) | - Calcium activating domains (CAD)

Question 63

How does Ca2+ entry occur?

Answer 63

Through clustering of Orai1 channels close to the puncta

Question 64

What is TRPC1?

Answer 64

A selective ion channel which conducts Ca2+ and is present on acinar cells

Question 65

How is TRPC1 activated?

Answer 65

By the polybasic-rich K domain on STIM1