Ingestion Of A Meal

Question 1

Bones of mastication

Answer 1

▪️skull and spine- anchors
▪️maxilla and mandible-key bone
▪️temporal
▪️hyoid

Question 2

Mastication Muscle innervation

Answer 2

▪️voluntary
-brain stem pattern generator-learned behaviour that can adjust which doing it
▪️mandibular branch of trigeminal nerve 5
▪️jaw unloading reflex-opens jaw if bit down on something hard- stops from breaking teeth

Question 3

Salivation

Answer 3

▪️tiggers
-mastication- feeds back into salivary nucleus (pons CN7 and medulla CN9) to salivary glands 
-taste
-smell
-anticipation- thinking about it 
▪️inhibits 
-fear

Question 4

Functions of saliva

Answer 4

▪️digestive-salivary amylase, lingual lipase
▪️tooth maintenance-dilution, clearance and buffering-HCO3
-if pH drops under 5.5 for an extended period of time leads to demineralisation of teeth-Ca comes out
-chewing gum helps to decrease time under 5.5
▪️lubrication- allows speech, mastication and swallowing (deglutition)
-salivary glycoproteins are sticky but rub over each other (mucous)
-makes a thin film which coats mouth and food which allow it to be swallowed
▪️antibacterial/anti-fungal- protective barrier, IgA, lysozyme

Question 5

Salivary glands secretion

Answer 5

▪️parotid-serous (watery)-lots of HCO3 for buffering - CN9
▪️sublingual- mucous-help coat mouth for talking (resting saliva)
▪️submandibular-mixed
-SL and SM CN7
▪️minor glands- mucous-stop secreting salvia when sleeping as it would be breathed out- but a small amount of mucosal saliva stops dry mouth

Question 6

Salivary glands structure

Answer 6

▪️grape like- cells connected by a stalk
▪️acinar cells
-mucous acinus-stains more red due to glycoproteins
-serous acinus
▪️saliva produced in cells washes down ducts
-intercalated duct, striated duct, excretory duct

Question 7

Acinar cells

Answer 7

▪️basally located nucleus 
▪️polarised cells 
-basolateral side is different from apical side 
▪️contains lots of secretory vesicles 
▪️endoplasmic reticulum

Question 8

Salivary secretion mechanism

Answer 8

▪️saliva-protein and fluid
▪️stimulus-secretion coupling:
-SNS-noradrenaline- G-protein receptor-cAMP- protein transcription, exocytosis, formation of secretory vesicles-protein release
-PNS- ACh- G-protein receptor- IP3- release Ca- Ca depended ion channels release K basally and Cl apically- salt moves from basal side to apical side, osmotic gradient, water follows-fluid release
▪️ IgA movement and secretion
-binds to polymeric immunoglobulin receptor (PlgR) on basal side, endocytose, released on apical side, small piece of receptor left on IgA