physiology of the mouth and oesophagus

Question 1

what are the 3 pairs of salivary glands

Answer 1

parotid
submandibular
sublingual

Question 2

how much saliva secreted each day

Answer 2

1500ml

Question 3

what does saliva contain

Answer 3

• mucous to help lubricate food
• a-amylase to initiate breakdown of carbohydrate
• lysozyme (antibacterial actions)

Question 4

what is the formation of saliva

Answer 4

• isotonic fluid is produced by acinar cells, they secrete electrolytes and water
• fluid is modified as it flows along salivary duct
• final composition depends upon flow rate and neuronal input

Question 5

what controls saliva secretion

Answer 5

reflexes mediated via ANS

Question 6

what type of saliva does the parasympathetic system produce and how does it impact blood flow

Answer 6

• watery saliva
• rich in amylase and mucous
• increased blood flow to glands

Question 7

what type of saliva does the sympathetic nerve produce and how does it influence blood flow

Answer 7

• overall effects a reduction in secretion of watery saliva
• promotes increased output of thicker mucous
• reduces blood flow to glands

Question 8

what happens during the voluntary stage of swallowing

Answer 8

the tongue pushes bolus backwards to orthopharynx

Question 9

what happens during the pharyngeal stage of swallowing

Answer 9

• soft palate and uvula move up to seal off nasopharynx
• larynx raised and the glottis is sealed
• epiglottis covers glottis and breathing is suspended for 1-2secs

Question 10

what controls the pharyngeal stage of swallowing

Answer 10

it is a reflex action controlled by deglutition centre in medulla and pons of brain

Question 11

what is the first third of the tube that connects the laryngopharynx to the stomach

Answer 11

the muscularis layer striated to assist in swallowing

Question 12

what is the middle third of the tube that connects the laryngopharynx to the stomach

Answer 12

a mix of striated and smooth muscle

Question 13

what is the lower third of the tube that connects the laryngopharynx to the stomach

Answer 13

all smooth muscle

Question 14

what needs to be considered when using buccal route

Answer 14

• drug must dissolve in saliva so hydrophobicity is an issue
• need to consider swallowing reflex for buccal delivery - retention in mouth important
• surface area for absorption is limited 200cm vs 20,000cm (skin)

Question 15

characteristics of oral mucosa

Answer 15

• surface area is limited
• passive diffusion
• rich blood supply - rapid onset of action with similar bioavailability to iv formulation

Question 16

barriers to oral delivery

Answer 16

• drugs must diffuse across lipophilic cell membrane and hydrophilic interior of cell
• enzymatic barrier in buccal tissue also exists causing rapid degradation of peptides and proteins (limits transport across epithelium)

Question 17

challenges of buccal delivery

Answer 17

• barriers
• drug must be kept in place for absorption. excess saliva could reduce this
• surface area limited
• taste of drug must be bland
• drug must be non irritant to mouth or teeth

Question 18

what can dry mouth cause and what can it affect

Answer 18

oral ulcers and dental caries.
can affect digestion and drug absorption.

Question 19

how can dry mouth be treated

Answer 19

with artificial saliva preparations (lozenge/spray/gel)

Question 20

how are oral ulcers treated

Answer 20

they usually clear up w/o treatment

sometimes require anti-inflammatory and antimicrobial mouthwash to prevent infection

Question 21

what causes oral thrush

Answer 21

• overuse of antibiotics
• poor immune system
• underlying disease
• smoking
  dentures

Question 22

how is oral thrush treated

Answer 22

treatment is aimed at reducing fungal infection using oral anti-fungal gel
eg miconazole

Question 23

how do antacids cause tooth decay

Answer 23

may contain sugar or artificial sweeteners

chewable antacids can get stuck between your teeth and over time can result in decay

Question 24

how can pain medications cause tooth decay

Answer 24

opioids can cause dry mouth and the consequent erosion of tooth enamel

Question 25

how can antihistamines cause tooth decay

Answer 25

they can block the release of saliva, resulting in dry mouth

Question 26

how can inhalers cause tooth decay

Answer 26

they contain an ingredient that is slightly acidic and can be harmful to tooth enamel