Lecture 9

Question 1

3 pairs of salivary glands?

Answer 1

parotid (watery), submandibular (watery), sublingual (thick)

Question 2

What does saliva contain?

Answer 2

Mucous (lubricates food), amylase (breaks down carbohydrate-starch), lysozyme (antibacterial actions)

Question 3

How is saliva formed?

Answer 3

Isotonic fluid is produced by acinar cells (secrete electrolytes/water), fluid is modified as it flows along salivary duct according to signals received, final composition depends on flow rate + neuronal input

Question 4

Parasympathetic input for saliva secretions?

Answer 4

Watery + rich in amylase + mucous, increased blood flow to glands (rest/digest - about to eat tasty food -> mouth watering)

Question 5

Sympathetic input for saliva secretions?

Answer 5

Promotes increased output of thicker mucous, reduces blood flow to glands, reduction in secretion of watery saliva (fight/flight - anxious -> mouth dry)

Question 6

Deglutition?

Answer 6

Swallowing process

Question 7

Stages of deglutition?

Answer 7

Voluntary stage, pharyngeal stage

Question 8

Voluntary stage of swallowing?

Answer 8

Tongue pushes bolus (chewed food) backwards to orthopharynx (middle part of throat)

Question 9

Pharyngeal stage of swallowing?

Answer 9

Is a reflex action: soft palate and uvula move up -> seals off nasopharynx, larynx raised, glottis (valve between mouth/lungs) sealed, epiglottis covers glottis -> breathing suspended for 1-2 seconds (prevents food going down trachea into lungs)

Question 10

Role of segmentation?

Answer 10

Facilitates mixing of food - contract/relax, occurs largely in small intestine (circular muscle)

Question 11

Role of peristalsis?

Answer 11

Propels food along tract (longitudinal muscle)

Question 12

Why absorption through mouth results in rapid action?

Answer 12

Drug must cross epithelium (oral mucosa), enters bloodstream directly -> greater bioavailability, no need to go through digestive system (avoids first pass metabolism: drug absorbed via gut wall)

Question 13

Problems with absorption through mouth?

Answer 13

Solubility in saliva (hydrophobicity is an issue), only small lipophilic molecules well absorbed (will drug diffuse passively?), barrier to absorption which are hard to overcome

Question 14

Important features of oral mucosa?

Answer 14

Limited SA for absorption, rich blood supply leading to rapid onset

Question 15

Barriers to oral delivery?

Answer 15

Drug must diffuse across lipophilic cell membrane and hydrophilic interior of cell
Enzymatic barrier (aminopeptidase) in buccal tissue - causes rapid breakdown of peptides/proteins -> limits transport across epithelium, may degrade the drug

Question 16

Challenges for buccal delivery?

Answer 16

Drug must be kept in place (excess saliva reduces this)
SA limited
Taste of drug must be bland
Drug must be non-irritant to mouth/teeth

Question 17

Xerostomia?

Answer 17

Dry mouth

Question 18

About xerostomia?

Answer 18

Leads to ulcers which affects digestion/drug absorption, can be side effect of certain drugs, trated with artificial saliva preparations (spray)

Question 19

About oral ulcers?

Answer 19

Usually clear up without treatment, but can require anti-inflammatory (corticosteroid) + anti-microbial mouthwash (prevent infection)

Question 20

About oral thrush (yeast infection)?

Answer 20

Caused by antibiotic overuse/poor immune system/smoking/dentures…, treated with oral anti-fungal gel (e.g. miconazole) - reduces fungal infection

Question 21

Meds that may cause tooth decay?

Answer 21

Antacids - can contain sugar/artificial sweeteners, get stuck in teeth
Pain meds - opioids cause dry mouth -> erosion of tooth enamel
Antihistamines - block release of saliva -> dry mouth
Inhalers - contain beta-adrenergic agonist (slightly acidic) -> harmful to tooth enamel

Question 22

Advice to maintain good dental hygiene?

Answer 22

Drink plenty water
Brush teeth twice day
No smoking
Reduce coffee, tea, alcohol: cause dehydration
Hydrate mouth - use mouth spray/rinse