Mouth and Swallowing

Question 1

what are the movements of chewing

Answer 1

lower jaw from side to side and up and down
elevation and depression
protraction and retraction
medial and lateral movement

Question 2

what are the 3 major salivary glands

Answer 2

parotid gland (lateral cheek)
sublingual gland under tongue
submandibular

Question 3

what are the roles of saliva

Answer 3

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

Question 4

what controls salivary production

Answer 4

almost entirely due to neural control

Question 5

what is the para vs symptoms effect on saliva

Answer 5

more watery = para

more mucoid = symp

Question 6

PS control is in the salivary centre in the brain which is driven by what

Answer 6

local stimuli (taste and touch in the mouth) 
central stimuli (smell and sight of food) 
learned reflex

Question 7

describe the two stage process of the salivon

Answer 7

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

Question 8

describe the anatomy of a salivary gland

Answer 8

acinus (bulb) surrounded by myoepithelial cells
then intercalated duct
striated duct
excretory duct
main collecting duct emptying into the mouth

Question 9

what is the role of the parotid gland

Answer 9

largest salivary gland
mainly serous secretion
produces about 50% of volume
main source of salivary amylase and proline rich proteins

Question 10

what are the nervous inputs to the parotid gland

Answer 10

para - CN 9 - glossopharengyeal

symp - superior cervical ganglion

Question 11

what is the role of the submandibular gland

Answer 11

mixed serous and mucous secretion
about 45% of salivary volume
main source of lysozyme and lactoperoxidase

Question 12

what are the nervous inputs to the submandibular gland

Answer 12

para - CN 7
(facial - chorda tympani - lingual nerve)
symp - superior cervical ganglion (travels with facial artery)

Question 13

what is the role of the sublingual gland

Answer 13

mainly mucous secretion
about 5% of salivary volume
mian source of lingual lipase

Question 14

what is the nervous input to the sublingual gland

Answer 14

para - CN7 (facial)

symp - superior cervical ganglion

Question 15

what are the two types of starch and large polysaccharides

Answer 15

a-1,4 and a1-6 (branches)

Question 16

what is the role of ptyalin a amylase

Answer 16

cuts a1-4 sites

optimum ph around 7 an denatures at 4

Question 17

what is the role of lingual lipase

Answer 17

cleave the outer fatty acids off triglycerides, leaving diacyl glycerol
optimum ph about 4 (stable in stomach but denatured by pancreatic proteases)

Question 18

what are the 3 types of papillae on the tongue

Answer 18

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

Question 19

describe the anatomy of a taste bud

Answer 19

taste pore on surface with microvilli
contains taste cells and supporting cells
taste cells synapse with sensory neurones

Question 20

what are the two types of specialised epithetical cells of taste sensors

Answer 20

ion channel based sensor

GPCR based sensor

Question 21

what tastes do ion channel based sensor detect

Answer 21

salty and sour

Question 22

what tastes does GPCR based sensors detect

Answer 22

sweet
umami
bitter

Question 23

what channel is stimulated by salty

Answer 23

ENaC on ion based

leads to Na influx and depolarisation which leads to Ca influx and NT release

Question 24

what does a sour stimulus activate

Answer 24

TRPP on ion channel based sensor

Na influx - Ca influx and NT release

Question 25

what does a bitter taste do in taste buds

Answer 25

bound to gustducin, PLC, PIP2 which activates DAG and IP3 - IP3 leads to Ca influx from ER and outside cell and therefore NT release

Question 26

what are the stages of swallowing

Answer 26

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

Question 27

what are the size parameters of the oesophagus

Answer 27

25 cm long and 2 cm wide

Question 28

what are the cells in the oesophagus

Answer 28

stratified squamous epithelium, thrown into folds

submucosal oesophageal glands secrete mucus to facilitate movement

Question 29

what innervates the oesophagus

Answer 29

fibres of the oesophageal plexus

Question 30

what is the cephalic phase of GI activity

Answer 30

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