Wold 1 Flashcards
Parotid
Parotid (Stensen’s) duct opposite upper second molar
Serous gland; produces a watery (serous) secretion
Parotid;
Major source of
amylase
Submandibular
Submandibular (Wharton’s) duct opens
beneath the base of the tongue
Submandibular gland
Mixed (serous and mucous)
Submand. gland;
Secretions include
water/electrolytes and mucin
Active at rest
Sublingual
Lesser sublingual (Rivinus’s) ducts anterior floor Mostly mucous
Minor glands located throughout the oral cavity.
Labial Palatine Buccal Lingual (von Ebner’s gland) Sublingual mucosae
Minor salivary glands
Secrete mostly
mucous except von Ebner’s
Minor salivary glands
Contribute
5-10% of total saliva
Minor salivary glands
Harbor
lymphocytes
Von ebner’s gland
Secrete
lingual lipase
Initiates fatty acid digestion
Salivon
Acinus -Acinar cells (blind sac) --Serous Cells (enzymes) --Mucous Cells (mucin) ----**Myoepithelial Cells Intercalated Duct Striated Duct Excretory Duct
Composition of Saliva
WATER 99.5%
INORGANIC SALTS
Sodium, potassium, chloride, bicarbonate
Other components: calcium phosphate and magnesium sulfate
ORGANIC COMPONENTS
Acinar Cellular Origin
Amylase, Lipase, Mucoproteins, Proline-rich proteins, Tyrosine-rich proteins (and many others)
Nonacinar Cell Origin
Lysozyme, immunoglobulin, growth factors, regulatory peptides (NGF)
pH highly buffered 6.7 to 7.4
Nonacinar Cell Origin
Lysozyme, immunoglobulin, growth factors, regulatory peptides (NGF)
Acinar Cellular Origin
Amylase, Lipase, Mucoproteins, Proline-rich proteins, Tyrosine-rich proteins (and many others)
Salivary Fluid Secretion
-Intracellular Na+ kept low
-Intracellular K+ kept high
-Intracellular Cl- high
-In unstimulated cells, Ca2+ levels are low, and Ca2+ activated K+ and Cl- channels are closed.
=Upon stimulation, Ca2+ opens the Cl- and K+ channels.
Na+ leaks through tight junctions to follow Cl-
Primary secretion
(acini)
freely —- permeable
H2O
Secondary modification
Duct
H2O impermeable
Mechanisms of ductal modification
Number of transporters distributed in polarized manner across cell
Reabsorb Na+ and Cl- but NOT H2O
Slow flow rates allow more reabsorption
Primary secretions
Acinar region freely permeable to water
Electrolyte composition unaffected by flow rate
plasma like composition (isotonic)
Secondary secretions
Ductal region impermeable to water
Electrolyte composition strongly affected by flow rate
Low rate=high [K]; high rate=high [Na]
hypotonic
Mucin
Most abundant
protein in saliva
Mucin
Predominately produced by
sublingual & submandibular glands
Mucin
——- protein
carb rich
Mucin
Improves
Salivary viscosity
Amylase
Predominately produced by
parotid gland
Amylase
Packaged in
zymogen granules
Amylase
Initiates the breakdown of
starch
Immune-associated proteins
Muramidase
Lyze
muramic acid in the cell wall of many bacteria
Calcium Binding Proteins
e.g.. PRP, TRP (e.g., statherin) Cystatins, histatins
Promote
mineralization of the enamel
Growth Factors
EGF (stimulates
gastric growth); NGF (imp. For sympathetic n.s
Autonomic Nervous System Innervation
1.Acinar cells
2. Ductal cells
3. Blood vessels
-Vasodilation
-vasoconstriction
4. Myoepithelial Cells
Have contractive properties
Parasympathetic
NT in salivation
Acetycholine
NT in salivation
Sympathetic
Norepinephrine
NT in salivation- Others
Substance P (SP) and vasoactive intestinal peptide (VIP) Neuropeptide Y (NPY) and Calcitonin Gene Related Peptide (CGRP)
Mechanoreceptors
Periodontal Ligament
Tastebuds
Afferent Impulses
Trigeminal
Facial
Glassopharyngeal
Synapse in
Trigeminal
Solitary Nucleus
Parasympathetic stimulation releases —– onto the ——- results in a ——.
ACh
acinar cells and
watery plasma-like secretion
Big Picture salivation
Muscarinic or Alpha-adrenergic receptor activation
Intracellular calcium release
Calcium activated K+ and Cl- channels
Increase luminal Cl- concentration
Intercellular sodium follow
Water follows
Protein secretion by PKA mediated exocytosis
Acetylcholine Primarily (some effect of Norepinephrine via α-adrenergic receptor) Opening of
Ca++ sensitive Cl- and K+ channels
Acetylcholine primarily
Increased
flow rate, lowered ductal modification
Norepinephrine
Protein rich saliva
-PKA-mediated exocytosis
Norepinephrine receptor;
β-adrenergic receptor
Acetylcholine receptor
Muscarinic or α-adrenergic
Anti-cholinergic Drugs
can lead to
xerostomia
Xerostomia Management
Stimulate
muscarinic receptors
- Pilocarpine—Ach agonist
- Treat symptoms
