OCB02-2019 Development of salivary glands

Question 1

What is the histology staining of salivary glands done with? why?

Answer 1

Using Periodic- Acid Schiff staining because H&E cannot stain glycoproteins very well

Question 2

What colour do acinar cells appear in histological stain?

Answer 2

Purple

Question 3

What colour do duct cells appear in histological stain?

Answer 3

pink

Question 4

What is the purpose of acinar cells?

Answer 4

produce saliva into the ducts

Question 5

What is the purpose of ductal cells?

Answer 5

Modify the saliva

Question 6

What do the parasympathetic and sympathetic nerves control with regards to saliva?

Answer 6

Control the flow rate and which proteins are secreted into the saliva

Question 7

What saliva does the parasympathetic NS result in?

Answer 7

Large amounts of thin saliva

Question 8

What saliva does the sympathetic NS result in?

Answer 8

Small amounts of thick saliva

Question 9

Once secretory components have formed in acinar cells, where do they travel?

Answer 9

Into intercalated ducts which lead to striated ducts

Question 10

What type of ducts are intercalated and striated ducts known as?

Answer 10

Intralobular ducts

Question 11

What are the cells of the ducts connected by?

Answer 11

Tight junctions

Question 12

What do blood vessels supply for the saliva?

Answer 12

The water content, but not proteins

Question 13

Where do major salivary glands develop from?

Answer 13

Oral ectoderm

Question 14

Where do minor salivary glands develop?

Answer 14

Oral ectoderm and endoderm

Question 15

What are the 5 stages of salivary gland development?

Answer 15

Initial bud formation
Pseudo-glandular 
Canalicular
Terminal Bud
Adult formation

Question 16

Which stages of development are embryonic?

Answer 16

Initial bud formation
Pseudo-glandular
Canalicular

Question 17

What stage of development is perinatal?

Answer 17

terminal bud formation

Question 18

When does initial bud formation take place?

Answer 18

Initial 6 weeks of embryogenesis

Question 19

What occurs during initial bud formation?

Answer 19

Thickening of the oral cavity ectoderm to form epithelial placode
Mesenchyme receives signals and it condenses as the placode expands

Question 20

What occurs in the pseudo glandular stage?

Answer 20

Branching occurs, and there are long projections of epithelial cells with terminal ends

Question 21

In the pseudo glandular phase, what promotes branching?

Answer 21

FGFs

Question 22

In the pseudo glandular phase, what antagonises branching?

Answer 22

BMPs

Question 23

What does mesenchyme control in the pseudo glandular phase?

Answer 23

It control influence on branching only and does not affect which salivary proteins are secreted

Question 24

When does the canalicular stage occur?

Answer 24

10 weeks in utero

Question 25

What occurs in the canalicular stage?

Answer 25

Apoptosis of central cells forms lumens

Question 26

What does failure of the canalicular stage result in?

Answer 26

Cause retention cysts/ ranulas which are a collection of fluid/saliva that becomes trapped in the mucosa

Question 27

When does terminal bud stage occur?

Answer 27

Around 16 weeks in utero

Question 28

What cells form acini in the terminal bud stage?

Answer 28

Type 3 cells

Question 29

What cells form striated ducts in the terminal bud stage?

Answer 29

type 1 cells

Question 30

When does the adult formation stage occur?

Answer 30

36 weeks in humans

Question 31

What occurs in the adult formation stage?

Answer 31

Development and integration of nerves | Nerves develop separately and attach to acini cells around birth

Question 32

What does the maturation of salivary glands depend on?

Answer 32

The interaction with nerves

Question 33

What proteins are present in neonates?

Answer 33

IgD sIgA Albumin

Question 34

What does the salivary protein shift from and to?

Answer 34

IgD to sIgA

Question 35

What defence builds in the first year?

Answer 35

Mucosal defence

Question 36

What are the influences on salivary gland development in adults?

Answer 36

Tooth eruption/ weaning/ mastication: there are mechanoreceptors which become activated, there is increased neural input to glands which causes secretion Puberty and menopause: hormones Age: Salivary protein profile changes so amylase is found. More fibrosis and fat deposits through age but this does not impede function. The is no age-related decline in salivary flow, but medications can cause xerostomia

Question 37

When does branching morphogenesis occur?

Answer 37

Pseudo-glandular stage

Question 38

When do nerves connect into acinar cells?

Answer 38

Perinatal/ adult formation

Question 39

From which tissue do myoepithelial cells develop?

Answer 39

Ectoderm

Question 40

Is amylase an embryonic or adult salivary protein?

Answer 40

Adult

Question 41

Which signalling molecule opposes FGF-signalling?

Answer 41

BMPs