1 C: Salivation Flashcards
What are the principal glands of salivation ?
How much secretion of saliva is seen daily?
1) Parotid
2) Submandibular
3) Sublingual glands
***800-1500 ml
What does salivary gland secretion aid in?
1) Lubrication and digestion of food
2) Enhance speech
3) taste
4) swallowing
Note: It also dissolves & wastes out food particles from between the teeth
What is Xerostomia?
What do patients suffer form?
Patients who can’t produce saliva ( a rare condition)
**Pt’s suffer from dental caries, dry mouth, and infection/inflammation of the buccal mucosa.
What are some diseases that affect salivary glands resulting in xerostomia?
1) Sjogren’s syndrome (autoimmune disease )
2) HIV/AIDS
3) Parkinson’s disease
4) Injury to head or neck that damages the nerves that stim salivary glands
5) radiation therapy for cancer of head/neck
What is normal salivary function mediated by?
Muscarinic M3 receptor
-Stimulation of this receptor results in increased watery flow of salivary secretions
What happens when normal oral mucosa is stimulated?
Afferent nerve signals travel to the salivary nuclei in the medulla
***Efferent nerve signals, mediated by acetylcholine also stimulates salivary glandular epi cells & increase salivary secretions.
What are the basic units of salivary glands consist of?
1) Acinus ( blind end of a branching duct system)
2) intercalated duct
3) striated duct
What is the acinus comprised of?
A central lumen surrounded by pyramidal- shaped cells. Surrounded by myoepithelial cells
What are myoepithelial cells? Where are they present?
Elongated or star-shaped non-secreting cells w/ long branching processes.
**Present in the intercalated DUCTS
What happens when myoepithelial cells are stimulated?
When stimulated by neural input, the myoepithelial cells CONTRACT to eject saliva into the MOUTH.
What are Acini classified as?
1) Serous
2) Mucous
3) Mixed
The Parotid gland is what Acinar type, Viscosity and % of unstimulated saliva?
Serous, and watery
**25 % of saliva
The Submandibular gland is what Acinar type, Viscosity and % of unstimulated saliva?
Mixed and semi-viscous
**71% of saliva
The Sublingual gland is what Acinar type, Viscosity and % of unstimulated saliva?
Mucous and Viscous
**3-4 % of saliva
The Minor gland is what Acinar type, Viscosity and % of unstimulated saliva?
Mucous and Viscous
**Trace %
The Stensen’s DUCT drains the _____________ gland. Where is it located?
Parotid gland
***Located near the upper 2nd molar
The Wharton’s DUCT drains the _____________ gland. Where is it located?
Submandibular gland
***Located at the base of the understructure of tongue
What is unique about the Sublingual gland?
Unlike the parotid or submandibular it LACKS a SINGLE DOMINANT DUCT.
Where does the Sublingual gland drained by?
Approximately 20 small ducts called the DUCTS of RIVINUS.
***Which exit the superior aspect of the gland & open along the sublingual fold on the floor of the mouth
What is the Saliva content ?
pH?
- 5% Water
0. 5 % Electrolytes and Protein ( pH 6.0-7.4)
What are the most important salivary proteins?
1) Salivary alpha-amylase
2) Lingual Lipase
3) Mucins
What is the Salivary alpha-amylase?
An enzyme that begins digestion of carbohydrates in the MOUTH
What are lingual lipase’s?
Enzymes that begin digestion of lipids in the STOMACH
What are mucins?
Mix w/ water to become mucus, which lubricates food
What do salivary alpha-amylase hydrolyze?
Internal alpha-1,4 linkages ONLY
**DOES NOT cleave terminal alpha-1,4 linkages OR alpha-1,6 linkages
What is Salivary alpha-amylase inactivated by?
Gastric acid
What are the specialized constituents of saliva w/ antibacterial actions?
1) lysozyme
2) Lactoferrin
3) Immunoglobulin A
What is lysozyme?
Attacks bacterial cell walls
What is Lactoferrin?
Chelates iron, preventing the multiplication of organism that require it for growth
What is Immunoglobulin A?
Active against certain viruses and bacteria
Oral bacteria include what ?
Streptococci, lactobacilli, staphylococci, corynebacteria, and various anaerobes in particular bactericides.
***700 species detected
What are the benefits or Normal Oral Cavity Flora?
1) Prevent colonization by pathogens by competing for attachment sites or for essential nutrients
2) May antagonize other bacteria they the production of substance which inhibit or kill non-indigenous species
3) Stimulate the production of cross-reactive antibodies; since the flora behave as antigens, they induce immunological responses, antibody-mediated immune (AMI) response
What does Saliva contain that can neutralize the acids (created by the bacteria that inhabit dental plaque) that cause tooth demineralization “tooth decay” ?
Buffering agents ( HCO3-)
What must be present for tooth re-mineralization to occur?
Minerals ( calcium, phosphorus)
Why does plaque pH fall each time acids accumulate in the mouth?
Due to bacterial acid production following the consumption of fermentable carbohydrates ***SUGARS in foods and drinks
What occurs wit inn 5-10 minutes of eating and drinking ?
The acids can cause the pH to drop to a level low enough
( < 5.5) for the minerals in the tooth’s enamel to be dissolved (demineralization)
***LEADS TO TOOTH DECAY
What does Saliva do ?
Neutralizes these acids & helps to repair the enamel by replacing the lost minerals (remineralization)
What does Fluoride do?
Enhances saliva’s role in the remineralization process
What is Salivary Secretion control under?
Neural control by CN 9 & 7
What is the continuous secretion of saliva in absence of stimuli due to ?
The constant low-level stimulation by the parasympathetic nerve endings that exterminate in the salivary glands
Why is the basal secretion important?
Keeps the mouth and pharynx moist at all times
When does an unconditioned salivary response occur?
When chemoreceptors and pressure receptors within the oral cavity respond to the presence of food
-When activated they initiate impulses in AFFERENT NERVE FIBERS that carry information to the salivary center of the MEDULLA
When touch and fast of food is sensed by receptors in the mouth, what happens?
Afferent neurons carry info to the CNS
What happens when the Salivary nuclei in the MEDULLA receive the information?
EFFERENT neurons of the parasympathetic nervous system carry information via the CN 7 and CN 9 to the salivary glands —> Salivary glands secrete saliva via the extrinsic autonomic nerves
For the Sympathetic System what is the a) Saliva input,
b) Temporal response, c) composition of secretions and
d) response to denervation?
a) Scant
b) transient (VISCOUS)
c) Protein RICH (High K+ and HCO3-)
d) decreased secretion
For the Parasympathetic System what is the a) Saliva input,
b) Temporal response, c) composition of secretions and
d) response to denervation?
a) copious (lots)
b) sustained
c) Protein POOR (low K+ and HCO3-)
d) Decreased secretion & gland atrophy
What stimulates increase salivary secretion?
Sympathetic and parasympathetic stimulation
***Quantity and characteristics are different
What exerts the dominate role in salivary secretion?
Parasympathetic stimulation, produces a prompt & abundant flow of watery saliva that is rich in enzymes
What can reduce Salivary secretion?
Atropine & other cholinergic BLOCKING AGENTS
What does sympathetic stimulation produce?
A smaller volume of thick saliva that is RICH in mucous
When does the mouth feel drier than usual ?
When the sympathetic stimulation elicits a smaller volume of saliva during circumstances when the sympathetic system is dominant such as stressful situations.
What stimulates and inhibits parasympathetic regulation of saliva ?
Stimulates: Conditioning, Food (sight, smell, and thought) , Nausea, and Smell
***Pavlov’s experiments
Inhibits: Dehydration, Fear, and Sleep
