Section 1C Flashcards
What is the daily secretion of saliva?
800-1500 mL
What are the 3 principle glands of salivation?
- Parotid
- Submandibular
- Sublingual
- also many small buccal glands…
3 functions of salivary gland secretions
- Lubrication and digestion of food
- Enhance speech, taste, and swallowing
- dissolves and washes out food particles from between teeth.
What is Xerostomia and what do they show as symptoms
patients who cannot produce saliva
- Suffer from 1)dental caries, 2)dry mouth and 3)infection/inflammation of the buccal mucosa
What diseases affect salivary glands resulting in xerostamia?
Sjogren’s syndrome
HIV/AIDS
Diabetes
Parkinson’s Disease
Other than disease and drugs, what else can cause Xerostamia?
- Injury to the head or neck that damages the nerves that stimulate the salivary glands
- Radiation therapy for a cancer of the head and neck that damage any or all salivary glands included in the field of radiation
The basic unit of the salivary gland consists of what three things
- Acinus (cluster of cells)
- Intercalated duct
- Striated duct
Each acinus is surround by a layer of what type of cells?
Myoepithelial cells, which are elongated or star-shaped non-secreting cells with long branching processes.
What is the purpose of myoepithelial cells?
When stimulated by neural input, the myoepithelial cells contract to eject saliva into the mouth.
Acini can be classified as one of three categories
- Serous (Completely serous cells)
- Mucous (Completely mucous cells)
- Mixed (combination of both)
Parotid glands have what type of acinus? What type of viscosity?
Serous Acinus
Watery viscosity
Submandibular glands have what type of acinus? WHat type of viscosity?
Mixed acinus
Semi-viscous viscosity
Sublingual glands have what type of acinus? What type of viscosity?
Mucous acinus
Viscous viscosity
What gland has the most percentage of whole unstimulated daily saliva and which has the least?
Submandibular has most (71%)
Sublingual has least (3-4%)
What duct drains the parotid gland?
Stensen’s duct, it is located near the upper second molar
What does Wharton’s duct do?
Drains the submandibular gland and is located at the base of understructure of tongue.
What duct drains the sublingual gland
It lack a single dominant duct. It is drained by 10 small ducts called the Ducts of Rivinus which exit the the superior aspect of the gland and open along the sublingual fold on the floor of the mouth
What is the composition of saliva?
Composed of about:
- 5% water
- 5% electrolytes and protein
What is the pH of saliva?
6.0-7.4
What are the three most important salivary proteins and their function?
- Salivary a-amylase (enzyme, begins digestion of carbs in mouth)
- Lingual lipase (enzyme, begins digestion of lipids in stomach)
- Mucins (mix with water to become mucus, which lubricates food)
Function of Salivary a-amylase
Hydrolyzes internal alpha-1,4 linkages only.
Does not cleave terminal alpha-1,4 linkages or alpha-1,6 linkages.
What inactivates salivary alpha-amylase?
It is inactivated by gastric acid
Which constituents of saliva have antibacterial actions?
- lysozyme (attacks bacterial cell walls)
- Lactoferrin (chelates iron, preventing the multiplication of organisms that require it for growth)
- Immunoglbulin A (IgA) which is active against certain viruses and bacteria
Name 4 specific oral bacteria
Streptococci Lactobacilli Staphylococci Corynebacteria - Other anaerobes, approx. 700 species have been estimated to be present
3 benefits of normal oral cavity flora
- Prevent colonization of pathogens by competing for attachment sites or for essential nutrients
- May antagonize other bacteria through the production of substances which inhibit or kill non-indigenous species
- Stimulate the production of cross-reactive antibodies; They act as antigents and induce an immunological response
What does saliva have to neutralize acids in the mouth that cause tooth demineralization?
Contain buffering agents, particularly HCO3-
What minerals does sliva contain that must be present for the tooth remineralization process to occur?
Calcium, Phosphorous
What pH is used to determine low enough for minerals in the tooth’s enamel to dissolve?
< 5.5, can occur within 5-10 minutes of eating
Salivary secretion is under what type of control for action?
Neural control. It is due to constant low-level stimulation by the parasympathetic nerve endings that terminate in the salivary glands.
What type of neural stimulation increases salivary secretion?
Both sympathetic and parasympathetic stimulate
Which type of stimulation exerts the dominant role insalivary secretion, produces a prompt and abundant flow of watery saliva that is rich in enzymes.
Parasympathetic
What stimulation produces a much smaller volume of thick saliva that is rich in mucus?
Sympathetic
What other things other than food in the mouth can cause salivary secretion?
Sight and smell
Thought can also do it
Upon stimulation, efferent neurons of the parasympathetic nervous system sends neural input via what cranial nerves to stimulate salivary glands to produce saliva?
CN VII and IX
What two main things act by blocking the parasympathetic nervous system and thus saliva release?
- Atropine
2. Other cholinergic blocking agents
What does the mouth feel like when the sympathetic nervous system is dominant?
It will feel dry because of the thick saliva
What three things may decrease parasympathetic action inhibiting saliva release?
Dehydration
Fear
Sleep
