L11 - Physiology of the Mouth and the Oesophagus Flashcards
1
Q
what is the function of the mouth
A
mix food with saliva as it is chewed
2
Q
how much saliva is secreted daily
A
around 1.5L
3
Q
what does saliva contain and why does it contian the components
A
- mucous to help lubricate food
- α-amylase to initiate breakdown of carbohydrate
- lysozyme
- enzyme involved in antibacterial actions
4
Q
A
5
Q
WHat are the three pairs of salivary gland
what are theur dufferebt functions
A
6
Q
how is saliva formed
A
- it is a isotonic flid produced by acinar cells
- secrete electrolytes & water
- f;uid moved as it flows along salivary duct
- final composition depends upon flow rate & neuronal output
7
Q
how is saliva secretion regulated
A
- controlled by reflexes mediated via ANS
- parasympathetic (rest and digest)
- watery saliva
- rich in amylase and mucous
- increased blood flow to glands
- sympathetic
- promotes increased output of thicker mucous
- reduces blood flow to glands
- overall effects a reduction in secretion of watery saliva
8
Q
deglutution
A
swallowing
9
Q
what are the stages of deglutition
A
- voluntary stage
- tongue pushes bolus backward to orthopharynx
- pharyngeal stage
- reflex action
- soft palate and uvula move up to seal off nasopharynx
- larynx raised, glottis sealed
- epiglottis covers glottis and breated suspended for 1-2s
10
Q
what controls the reflex action of the pharyngeal stage
A
controlled by deglutition centre in medulla and pons of brain
11
Q
What is the oesophagus
A
tube connecting the laryngopharynx to stomach
12
Q
how does the structure of the oesophagus change
A
- musccularus layer striated for first third to assist in swallowing
- skeletal muscle = stirated muscle
- middle muscle is mixture of stirated and smooth muscle
- lower third is all smooth muslce
13
Q
segmentation
A
- occurs larger in SI
- facilitate miscur of food
- circular muscle contract
14
Q
peristalsis
A
- concerned mainly with propulsion of food along tract
