Week 4 salivary gland Flashcards
Describe minor glands
Secrete continuously and are under local control - keep thinks lubricated
When do major glands secrete?
In response to parasympathetic activity which is induced by physical, chemical and psychological stimuli
How much saliva does a human produce a day?
600-1500ml
What is contained in hypotonic watery secretion?
- mucus
- enzymes (amylase,lipase,lysozyme)
- antibodies (lgA)
- inorganic ions
What will the composition of saliva depend on?
Which glands is most active
What are the functions of saliva?
- lubrication
- buffering
- maintaining tooth integrity
- antibacterial function
- taste and digestion
What does amylase digest?
Carbohydrates
What is the function of salivary mucous?
Lubrication, teeth protection
How are salivary glands innervated?
Directly, indirectly, sympathetically, parasympathetically
Nerves involved in innervation
Parotid gland - otic ganglion
Tongue - glossopharyngeal nerve
Tongue connected to glands via cranial nerves
What evokes a lot of saliva?
Parasympathetic stimulation
What carries the parasympathetic innervation to the salivary glands?
Cranial nerves
What influences saliva production?
Sight of food
Chewing
Gender
Mood
Taste
How does the parotid gland receive its parasympathetic input?
From the glossopharyngeal nerve (CN9) via the otic ganglion
By what nerve do the submandibular and sublingual glands receive their parasympathetic input from?
Facial nerve (CN7) via submandibular ganglion
Via what nerves does direct sympathetic innervation of the salivary glands come from?
Preganglionic nerves
What happens to the blood flow to secretory acini during salivary secretion?
Increased via parasympathetic stimulation and ultrafiltration from plasma (mostly serous fluid) enters the acini
What happens to the filtrate from cells?
- enters lumen of acinar cells
- mixing with secreted mucus and alpha-amylase
- creates primary secretion
How and where is the primary secretion modified?
- passed through the ducts in the mouth
- lingual lipase (secreted form vin Ebner glands of the tongue) added to saliva in mouth
name the main types of secretory cells
- serous cells
- mucous cells
What other gastrointestinal cell type is similar to serous cells in salivary glands?
Chief cells - produce pepsin - digestive enzymes
Describe serous cells
- zymogen granules: enzyme-containing and found apically
- nucei basally located rounded with dispersed chromatin
Describe mucous cells
- mucigen granules within these cells are poorly stained
- nuclei characteristically are flattened against basement membrane
Where can a serous demilune be found and what is it?
In mixed secretory units, where mucous cells predominate, a semilunar cap of serous cells is seen - serous demilune
where is mucous cells also found in?
Oesophageal submucosal glands
What does the salivary secretory unit consist of?
Terminal branched tubulo-acinar strcture
What type of cells can make up a terminal branched tubulo-acinar structure?
Serous, mucous secretory cells or a mixture of both
What and where is serous demilunes?
- in mixed secretory units where mucous cells predominate, serous cells often form serous demilunes
What is the job of myoepithelial cells?
Surround the secretory units to push saliva through
What lines intercalated ducts?
Secretory cells
What do intercalated ducts drain into?
Striated ducts
What creates striations?
Presence of interdigitations of the basal cytoplasmic processes of columnar lining cells
What do serous cells secrete?
A fluid isotonic with plasma
What happens in the striated ducts?
Ions are reabsorbed and secreted to produce hypotonic saliva containing less Na+/Cl- and more K+/HCO3- than plasma
What do mitochondria do in this process?
Pack the basal processes, provide the energy for ion transport
What is the pattern of the general architecture of the major salivary glands?
Pattern of the parotid gland
What is the gland divided into?
Numerous lobules, each containing many secretory units
Connective tissue septa radiate between…
Lobules from an outer capsule and carry blood vessels, nerves, large excretory ducts
What does the parotid gland consist of?
Mainly serous secretory units which are darkly stained in H&E
What do serous cells have?
- numerous zymogen granules - strongly stained cytoplasmic granules containing proteins
- nuclei rounded with dispersed chromatin, usually occupy a more central position within the cell
what are striated ducts?
- lined by tall columnar cells with large nuceli located towards the apex of the cell
Why is the basal cytoplasm striated in striated ducts?
Due to basal interdigitations of adjacent cells and columns of mitochondria
What are myoepithelial cells?
Surround the acini and force the secretions form the acinar lumen into the duct system
Where are myoepithelial cells located?
Located between basal plasma cell membranes of secretory cells and the basement membrane
How do myoepithelial cells look like?
Flattened cell with long cell processed which extend around the acinus
