Mouth and Swallowing Flashcards
what are the movements of chewing
lower jaw from side to side and up and down
elevation and depression
protraction and retraction
medial and lateral movement
what are the 3 major salivary glands
parotid gland (lateral cheek)
sublingual gland under tongue
submandibular
what are the roles of saliva
lubrication made of serous fluid and mucus
facilitation of taste
protection against acid and bacteria (contains antibacterial enzymes, lysosome, IgA, bicarbonate, calcium ions)
digestion (salivary amylase (ptyalin), lingual lipase
what controls salivary production
almost entirely due to neural control
what is the para vs symptoms effect on saliva
more watery = para
more mucoid = symp
PS control is in the salivary centre in the brain which is driven by what
local stimuli (taste and touch in the mouth) central stimuli (smell and sight of food) learned reflex
describe the two stage process of the salivon
initial isotonic fluid containing mainly NaCl, protein, mucus
as it passes along the duct there is salt reabsorption and HCO3 (and K) secretion which leads to hypotonic, alkaline fluid
describe the anatomy of a salivary gland
acinus (bulb) surrounded by myoepithelial cells
then intercalated duct
striated duct
excretory duct
main collecting duct emptying into the mouth
what is the role of the parotid gland
largest salivary gland
mainly serous secretion
produces about 50% of volume
main source of salivary amylase and proline rich proteins
what are the nervous inputs to the parotid gland
para - CN 9 - glossopharengyeal
symp - superior cervical ganglion
what is the role of the submandibular gland
mixed serous and mucous secretion
about 45% of salivary volume
main source of lysozyme and lactoperoxidase
what are the nervous inputs to the submandibular gland
para - CN 7
(facial - chorda tympani - lingual nerve)
symp - superior cervical ganglion (travels with facial artery)
what is the role of the sublingual gland
mainly mucous secretion
about 5% of salivary volume
mian source of lingual lipase
what is the nervous input to the sublingual gland
para - CN7 (facial)
symp - superior cervical ganglion
what are the two types of starch and large polysaccharides
a-1,4 and a1-6 (branches)
what is the role of ptyalin a amylase
cuts a1-4 sites
optimum ph around 7 an denatures at 4
what is the role of lingual lipase
cleave the outer fatty acids off triglycerides, leaving diacyl glycerol
optimum ph about 4 (stable in stomach but denatured by pancreatic proteases)
what are the 3 types of papillae on the tongue
folate which have serous glands between them (lateral posterior tongue)
circumvallate (posterior superficial tongue)
fungiform (taste buds more near surface) - found around the outer edges of the tongue
describe the anatomy of a taste bud
taste pore on surface with microvilli
contains taste cells and supporting cells
taste cells synapse with sensory neurones
what are the two types of specialised epithetical cells of taste sensors
ion channel based sensor
GPCR based sensor
what tastes do ion channel based sensor detect
salty and sour
what tastes does GPCR based sensors detect
sweet
umami
bitter
what channel is stimulated by salty
ENaC on ion based
leads to Na influx and depolarisation which leads to Ca influx and NT release
what does a sour stimulus activate
TRPP on ion channel based sensor
Na influx - Ca influx and NT release
what does a bitter taste do in taste buds
bound to gustducin, PLC, PIP2 which activates DAG and IP3 - IP3 leads to Ca influx from ER and outside cell and therefore NT release
what are the stages of swallowing
voluntary phase
pharyngeal phase - contraction of the glottis - nasopharynx closed, pharynx wall contracts and the epiglottis is pushed by the bolus to meet the larynx which moves upwards
trachea closed - upper oesophageal sphincter opening
oesophageal phase - bolus descends by peristaltic activity
what are the size parameters of the oesophagus
25 cm long and 2 cm wide
what are the cells in the oesophagus
stratified squamous epithelium, thrown into folds
submucosal oesophageal glands secrete mucus to facilitate movement
what innervates the oesophagus
fibres of the oesophageal plexus
what is the cephalic phase of GI activity
mediated by parasympathetic nervous system
- salivary secretion via facial and glossopharyngeal nerves ie 7 and 9
- control of GI motility and secretion via vagus CN 10
