Oral Physiology Flashcards
List all salivary glands
- Parotid gland: serous
- Submandibular: mixed
- Sublingual: mixed
- Von Ebner’s Glands: serous
- Other minor salivary glands: mucous
List components of saliva
- Water (most important component)
- Electrolytes (e.g. Bicarbonate and fluoride)
- Proteins:
1) Mucin, glycoproteins
2) Immunoglobulin (IgA)
3) Enzymes
4) Phosphoproteins
Describe the components of a saliva secretory unit
- Salivon -> basic unit of salivary gland
- Acinus -> berry-shaped cluster of cells; initial site of secretory process
- Intercalated duct -> Initial part of duct; contains secretory granules
- Striated duct -> Modifies secretory product
- Excretory duct -> Modify the saliva composition
Describe formation of saliva in primary secretion:
Isotonic saliva secreted by acinus and intercalated ducts.
- Ions pumped into acinus cells: NaK-ATPase, NaKCl symporter
- Channels on apical surface diffuse ions out
- Sodium passively passes between cells
- Water follows sodium.
Describe formation of saliva in secondary secretion
Hypotonic saliva after modifications from striated and excretory ducts.
- Na and Cl absorbed from lumen
- K and HCO3 secreted into lumen
- Water impermeability
Describe high flow rate and low flow rate
- High flow rate = Saliva is 70% the composition of plasma
- Low flow rate = very hypotonic; high potassium
Describe control of saliva
- Dual innervation: parasympathetic and sympathetic control: Act simultaneously
- Hormones affect composition
List saliva stimulation factors
- Taste, temperature, smell
- Physical stimulation
- Mastication and chewing
- Nausea
- Stimulated flow: rate = 1.0 - 2.0 mL/min; source = mostly submandibular -> mostly mucous
- Unstimulated flow: rate = 0.3-0.5 mL/min; source = mostly parotid -> mostly serous
Describe innervation/nervous control of saliva
Parasympathetic:
- Primary instigator
- CN9 - Otic ganglion to parotid
- CN7 - Submandibular ganglion to submandibular and sublingual glands
- ACh to muscarinic receptor
- Watery saliva
Sympathetic
- superior cervical ganglion of sympathetic trunk to external carotid, lingual and facial arteries
- Noradrenaline to adrenergic receptors
- Short increase in salivary secretion
- Viscous saliva
Describe saliva inhibition factors
- Medication
- Autoimmune (e.g. Sjogren’s syndrome)
- Infection or obstruction of gland
Describe the different types of cells in taste bud:
- Type 1: Irregular nucleus, dark granule; salt tasting
- Type 2: Big round nucleus; salt tasting
- Type 3: Intermediate cells
- Type 4: Basal cells
Describe taste modalities
G-protein coupled receptors:
- Umami
- Sweet
- Bitter
Channels:
- sodium
- Sour/carbonate
Describe taste sensing:
Taste buds innervated by:
- CN7 - Facial nerve
- CN9 - Glossopharyngeal nerve
- CN10 - Vagus nerve
Senses from taste buds go through: medulla -> pons -> cortex.
“Flavour” is the perception of taste.
Flavour is mostly smell.
Describe spicy
- Not a real taste
- Sensed by CN5 - Trigeminal nerve
Describe smell organ:
Olfactory epithelium:
- Nerves from olfactory bulb travel through cribriform plate and olfactory epithelium
- Olfactory glands produce mucus on surface.
- Mucous:
1) Protects olfactory nerve cilia
2) Media for dissolving chemicals for sensing.
