Histology of Salivary Glands: Week 1 Flashcards
What are the functions of saliva?
- protection
- buffering
- pellicle formation
- maintenance of tooth integrity
- antimicrobial action
- tissue repair
- digestion
- taste
___gland: largest of major salivary glands
associated with facial nerve
duct opens opposite __ molar
innervated by __nerves traveling with CN (Cranial Nerve) __ –>
otic ganglion –> ___ nerve
Parotid, 2nd maxillary, parasympathetic , IX, auriculotemporal
___ gland: located in ___ floor of mouth
duct opens into mouth via ___ ___
innervation: parasympathetic nerves running with ___ via chorda
tympani –> lingual nerve –> ____ ganglion –>
postganglionic nn
Submandibular, posterior, sublingual caruncle, VII (CN), submandibular
___ gland: smallest of major salivary glands
located in floor of mouth ___to tongue
open into floor of mouth via many small ducts, and at ___ ___
innervation: same as submandibular glands
Sublingual, lateral, sublingual
caruncle, VII (CN)
Minor salivary glands are found throughout entire oral mucosa except…?
Anterior palate and gingiva
There are ___ minor salivary glands in number and they are mostly ___, however von Ebner’s glands on tongue are pure ___
600-1000, mucous, serous
Development of salivary glands
Salivary glands arise from __ and grow into surrounding __and remain connected to __ by cords of epithelial cells. Mesenchymal cells condense around __, branching morphogenesis.
oral epithelium, ectomesenchyme, surface epithelium, gland bud
Development of salivary glands
*lumen appears in __ cord and branch cords,
then in __ cord, and then in __ of
main cord
*two layers of cells:
* inner layer differentiates into __
* outer layer differentiates into __,
__ and __
distal, proximal, center, secretory cells, myoepithelial cells, capsule, septa
secretory end pieces resembling cluster of grapes (each grape made up of a group of 8-10 cells) and secrete __ __ into common lumen
Acini (acinus sing.), primary saliva
acinus means “berry”
Stroma is made up of __ and __
Lobe is made up of __
Parenchyma is made up of __ __
septum and capsule
lobules
secretory acini (parenchyma is cluster made up of individual acinus)
*acinus = secretory portion; @ apex of acini are secretory vesicles
*duct = conducting portion
Serous cells produce fluid rich in __ and __
proteins, glycoproteins
Serous acini are __; cells are __-shaped, nuclei are __ and __ located, secretory granules are located apically (contain macromolecules).
What organelles are located in the basal part of the cell?
spherical, pyramid, spherical, basally
organelles: rER, Golgi, mitochondria, lysosomes, etc., located in
basal part of cell
Membrane modifications of serous cells are:
short microvilli
* lateral interdigitations
* basal infolding
* junctional complexes, hemidesmosomes, gap junctions
* intercellular canaliculi are finger-like projections of lumen
between adjacent cells – increase lumen surface are
Mucous cells produce __ that are rich in __
mucins, glycoproteins
Mucus produced by mucous cells functions by…
- lubricating and forming a surface barrier
- binding and aggregating microorganisms
Mucous cells secretory and end pieces are __, and mucous acini sometimes associate with __ demilunes.
tubular, serous
__ part of cell contains large quantities of mucins
* __, __ compressed against basal membrane
* in routine H&E, cells appear empty; special stains
reveal mucous content
* cells joined by junctional complexes
* cells lack intercellular __
apical, nucleus, rER compressed, canaliculi
Myoepithelial cells: contractile - similar to smooth muscle, but derived
from __ rather than mesenchyme
epithelium
myoepithelial cells surround __ and __ __
acini, intercalated ducts
myoepithelial cells are located between __ __ and __ __ or ducts- attached by hemidesmosomes
Basal lamina, secretory cells
myoepithelial cells have multiple processes containing actin and myosin,
with __
actin, caveolae
What’s the role of myoepithelial cells?
- support secretory cells – help expel primary saliva
- help maintain duct patency (openness; lack of obstruction)
Intercalalted ducts…
- receive primary saliva from secretory cells
- add lysozyme and lactoferrin to saliva
Intercalated ducts…
- begin within the acini
- lined by simple squamous/cuboidal epithelial cells, features: (central nuclei, rER, Golgi, secretory granules, apical microvilli, junctional complexes, desmosomes, gap
junctions, interdigitating lateral membranes) - surrounded by myoepithelial cells
Striated ducts
- receive primary saliva from intercalated ducts
- form major portion of duct system
Striated ducts are made up of columnar cells, their features are…
centrally located nucleus, acidophilic cytoplasm
* basal striations = mitochondria + membrane infoldings
* surrounded by basal lamina and capillary plexus
* contain secretory granules, lysosomes, peroxisomes, glycogen
* tight junctions, junctional complexes; no gap junctions
Excretory ducts
located in CT septa between lobules
excretory ducts have what cell type?
- pseudostratified to stratified epithelium, attached to basal lamina by hemidesmosomes
Other cells found in excretory ducts
tuft cells with long stiff microvilli and apical vesicles –might be receptor cells: associated with nerve endings
* lymphocytes, macrophages, dendritic cells – found in base of duct epithelium
slide 36 for image
What are the connective tissue components of salivary glands?
- capsule
- septa
* divide gland into lobes and lobules
* transmit blood vessels, nerves and excretory ducts - fibroblasts, macrophages, dendritic cells, mast cells, plasma cells (IgA), adipose cells, some granulocytes and lymphocytes
- collagen and elastic fibers
Nerve supply of salivary glands: parasympathetics
- preganglionics
- from superior and inferior salivatory nuclei
- run with VII and IX
Nerve supply of salivary glands: parasympathetics
- postganglionics
- synapse in submandibular or otic ganglion
- run with lingual or auriculotemporal nerve
slide 39
Nerve supply of salivary glands: sympathetics
- follow vessels
- modulate secretion by controlling blood flow to glands
Nerve supply of salivary glands: neurotransmitters
- acetylcholine and norepinephrine
- substance P and VIP:
- induce secretion, modulate effects of acetylcholine and norepinephrine, might affect blood flow
- neuropeptide Y and CGRP
- regulate blood flow
Blood supply of salivary glands
*blood is source of fluid and electrolytes
*arterioles -> capillary networks
*blood flow to glands increases during secretion
*increased pressure in capillaries and venules
causes increased production of saliva
Acinus type in parotid gland
- said to be pure serous
- some fat cells present between acini
- numerous, long intercalated ducts
- numerous striated ducts
Acinus type in submandibular glands
*mixed acini, mostly serous
* intercalated and striated ducts less numerous than in parotids
slide 45
Acinus type in sublingual gland
- mixed, predominately mucous
- ducts short and difficult to see
slide 45
Acinus type in minor salivary glands
- mostly mucous, short ducts
- secretions rich in mucins, antibacterial proteins, immunoglobulins
von Ebner’s glands
* located on tongue, associated with circumvallate papillae
* secrete enzymes and proteins thought to play a role in taste
slide 47 & 48
How is saliva formed?
production & secretion of primary saliva by acinar cells
*primary saliva is isotonic with blood
the macromolecular components of 1o saliva are: produced by rER
- chaperone proteins ensure proper folding
- posttranslational modifications occur in cisternae
- proteins are transferred to Golgi in vesicles
What happens to the macromolecular components of primary saliva after it is produced?
- modified, condensed and packaged by Golgi
- stored in secretory granules in apical part of cell
- under stimulus, they fuse with the apical membrane
- contents are released to the lumen by exocytosis
Where do the fluid and elcetrolyte portions of primary saliva come from ?
Blood
When forming primary saliva what kind of innervation is water secretion regulated by?
parasympathetic
Saliva is modified by what type of cell and by what mechanisms? What regulates those mechanisms?
**Duct cells
**
* transporters cause reabsorption of Na+ and Cl-
* K+ and HCO3- are secreted
* regulation of these actions by
* autonomic nerves
* mineralocorticoids
Effects of age on saliva glands are…
- loss of salivary gland parenchymal tissue; replaced by adipose tissue
- reduced saliva production
Effect of disease on saliva glands
some viruses infect and replicate
within salivary gland cells:
* cytomegalovirus
* Epstein-Barr virus
* herpes viruses 6 & 7
* mumps
some bacterial infections cause
inflammation and swelling of
salivary glands
Effect of disease on saliva glands cont’d pt. 1
ducts can be obstructed by:
* sialoliths (salivary stones, calculi)
* mucus plugs
* trauma to the ducts
various tumors can affect the glands
* pleomorphic adenoma
* Warthin’s tumor
* etc.
Effect of disease on saliva glands cont’d pt. 2
other diseases can affect salivary gland function:
* diabetes
* Sjögren syndrome
* rheumatoid arthritis
* adrenal disease
* AIDS
Age and disease can drastically effect the salivary glands, which can result in xerostomia…
dry mouth
* due to loss of salivary function or reduction of saliva volume
xerostomia can be a result (side-effect) of the following:
- medication
- radiation therapy
- chemotherapy
- autoimmune disease
Xerostomia results in…
- dryness of mouth
- loss of protective effects of salivary buffers, proteins and
mucins - oral tissues becoming more susceptible to infections
- speech, eating and swallowing to become difficult
- teeth become more susceptible to caries
