Flashcards in Salivary glands Deck (27)
What does salvia do for protection?
Liquid flushes away non-adherent bacteria, debris, sugars, etc. Mucins provide lubrication for oral tissues to move over one another
what does salvia do for buffering?
Bicarbonate protects teeth from bacterial acids
what does salvia do for tooth integrity?
High levels of calcium and phosphate helps enamel to mature and increases hardness and resistance to demineralization
what does salvia do for antimicrobial activity?
Mucins provide a barrier; a number of proteins have antibacterial properties (e.g. lysozyme); immunoglobulins agglutinate bacteria
what does salvia do for digestion?
Fluid and mucin components aid in the formation and swallowing of a food bolus; enzymes such as amylase begin the process of breaking food down
what does salvia do for taste?
Saliva helps solubilize food so that it can interact with taste receptors
what are the 3 pairs of salivary glands?
- submandibular glands
Describe parotid glands.
Largest salivary glands.
Pyramidal shape with apex below angle of mandible, posterior edge is near external auditory meatus.
Parotid duct emerges from the anterior border, passes over masseter and pierces buccinator, emptying into the oral cavity on a papilla opposite the upper second molar tooth.
External carotid artery, retromandibular vein and facial nerve are all embedded in the gland
what is the parasympathetic innervation of the parotid gland?
Preganglionic: glossopharyngeal - lesser petrosal nerve- otic ganglion
otic ganglion- auriculotemporal nerve - parotid gland
Describe submandibular glands.
Superficial part visible below inferior border of the mandible, the gland wraps around the posterior border of the mylohyoid muscle, where there is a smaller deep portion of the gland.
Submandibular duct emerges from the deep part of the gland and passes forward to terminate on the sublinqual caruncle near the base of the lingual frenum.
Facial artery grooves the superficial part of the gland
what is the parasympathetic innervation of submandibular and sublingual glands?
Preganglionic: facial nerve - chorda tympani - lingual nerve - submandibular ganglion
Postganglionic: submandibular ganglion - submandibular gland
Describe sublingual glands.
Almond shaped, it sits in the sublingual fossa of the inner aspect of the mandible, bounded above by the oral mucosa, below by the mylohyoid muscle, and medially by the genioglossus muscle.
The sublingual ducts vary, but typically the anterior part drains via a single duct that joins the submandibular duct, and the posterior part drains via several small ducts that end on the sublingual fold
Describe a stroma.
Covered by a tough connective tissue capsule with septa of connective tissue that pass inward and subdivide the gland into lobes, that in turn are subdivided into lobules. Blood vessels, nerves and major ducts travel in these septa
Describe a parenchyma.
Compound tubulo-acinar glands.
Secretory elements consist of serous acini, mucous acini and mixed acini, although the type present depends upon the gland.
Secretion produced by merocrine secretion
what are the two classifications of salivary glands?
Serous- thin watery secretion that contains proteins
Mucous- secrete mucin, which consists of a protein core that is highly decorated with sugar residues and results in a viscous, sticky secretion
Describe cells of the serous acini.
Cells are typically wedge shaped and have a prominent nucleus in the basal part of the cell. They have extensive rough endoplasmic reticulum and a granular appearance due to large numbers of apical secretory vesicles
Describe cells of the mucous acini
Mucous cells tend to be found in the tubular element of the tubulo-acinar glandular structure. The cells have large numbers of prominent secretory granules packing the cytoplasm. When the tissue is processed using routine methods, these granules are large and compress the nucleus toward the basal part of the cell
what is serous demilune?
In salivary glands with mixed acini the serous cells in routine preparations often appear as a crescent shaped collection of cells at the end of the secretory unit
How are secretions expelled from the gland?
Myoepithelial cells - population of epithelial cells that have become specialized for contraction. These cells form a network around the groups of secretory cells and when they contract, help to expel the secretions from the gland
what is the duct system of major salivary glands?
-The acinus empties into an intercalated duct, consisting of cuboidal cells
-The intercalated duct empties into a striated duct
- striated ducts empty into excretory ducts (collecting ducts)
-the excretory merge and the duct becomes larger and near the opening of the oral cavity the lining of the duct becomes stratified squamous epithelium
Put the glands in order of higher serous:mucous ratio of cells to lowest
parotid- submandibular - subligual
where are minor salivary glands found?
Minor salivary glands are found scattered throughout the oral mucosa, although they are absent from the gingiva and the anterior part of the hard palate
Describe minor salivary glands.
They are predominately mucous in form and exhibit a continuous, slow secretory activity. They account for about 10% of salivary volume
Give some examples of minor salivary glands
-Minor sublingual glands found associated with the lower surface of the tongue.
-Labial glands on the inner surface of the lips.
-Palatine glands in the submucosa of the soft and posterior hard palate
Describe taste buds.
These multicellular chemoreceptive units span the epithelium and are about 50µm in diameter. They include taste cells (sensory cells), support cells and basal cells. Molecules enter the pore and then interact with receptors on microvilli on the sensory cells. The cells lack axons, but release neurotransmitter to stimulate afferent nerve fibres
Describe the innervation of the salivary glands
Receive both parasympathetic (transmitter: acetylcholine) and sympathetic (transmitter: noradrenalin) innervation