Lecture 9

Question 1

Why is it important that food is mixed with saliva as it is chewed ?

Answer 1

For lubrication and digestion.

Question 2

Three key pairs of salivary glands

Answer 2

Parotid, submandibular, sublingual.

Question 3

Where are these salivary glands found ?

Answer 3

They are adjacent to the mouth.

Question 4

How much saliva is excreted into the mouth each day ?

Answer 4

1500ml

Question 5

Why is fluid intake important ?

Answer 5

It is important in maintaining a balance in the body when it is producing so many secretions.

Question 6

What is saliva made up of ?

Answer 6

Mucus - helps to lubricate food.
Enzymes - initiate the digestion process, i.e. begins the breakdown of carbohydrates/starch, e.g. a-amylase and lysozyme.

Question 7

Parotid salivary gland

Answer 7

Produces watery saliva rich in a-amylase.

Question 8

Sublingual salivary gland

Answer 8

Produces thick saliva with thick mucus.

Question 9

Submandibular salivary gland

Answer 9

Produces watery saliva rich in a-amylase.

Question 10

Why is the tyre of saliva produced regulated stringently ?

Answer 10

As it is dependent on whether there is food to be processed in the mouth or not.

Question 11

Where does the food travel to at the start of the digestion process ?

Answer 11

The food travels to the back of the mouth, pharynx and then down the oesophagus.

Question 12

What runs parallel along beside the oesophagus ?

Answer 12

The trachea.

Question 13

Why is it important for there to be strict procedures and mechanisms in place for the transport of food down the oesophagus ?

Answer 13

So that the food moves down the oesophagus and not the trachea and to the lungs.

Question 14

Where is the saliva produced ?

Answer 14

Saliva is produced in the acing cells.
As the saliva flows through the salivary duct, the different cells secrete electrolytes and water to modify the saliva production.

Question 15

What is saliva production subject to ?

Answer 15

It is subject to neuronal input, which is the most important out the three for production of saliva.

Question 16

What are the reflexes involved in the neuronal input to the saliva production mediated by ?

Answer 16

They are mediated by the ANS, i.e. the parasympathetic and sympathetic systems are important in modulating the saliva production.

Question 17

The purpose of the parasympathetic arm of the ANS

Answer 17

Important in rest and digest.
Stimulate digestion and activate GI tract activity.
Watery saliva.
Increases the blood flow to the gland which produces saliva rich in amylase (digestive enzyme) and mucus.

Question 18

The purpose of the sympathetic arm of the ANS

Answer 18

Important in fight or flight.
Does not promote digestion - reduces GI tract activity.
Promotes increased output of thicker mucus which does not contain much enzyme activity.
Reduces blood flow to the glands.
Overall results in a reduction in secretion of watery saliva.

Question 19

There are very different compositions of saliva produced depending on…

Answer 19

… the neuronal input via the parasympathetic or the sympathetic.

Question 20

The process of swallowing/deglutition - step 1

Answer 20

The initial voluntary stage.

Where it is decided by the person to push the food to the back of the mouth to the pharynx.

Question 21

The process of swallowing/deglutition - step 2

Answer 21

The pharyngeal stage of swallowing.
It is a reflex action controlled by the deglutition centre in the medulla and pons of the brain.
The soft palate moves up to allow the bolus to move towards the oesophagus.

Question 22

What is the purpose of the epiglottis ?

Answer 22

It moves down to cover the glottis and the trachea so that the food moves down the oesophagus.
Breathing is stopped for a very shirt period of time when this happens.

Question 23

What happens if food accidentally moves down the trachea ?

Answer 23

The automatic response is to cough which helps to food to come back up again and therefore allowing the food to be swallowed properly and transported too.

Question 24

Why is it that food can move down the oesophagus ?

Answer 24

Because of the muscularis all along the GI tract which allows for the movement of food through the tract and allows for the food to be mixed as it travels through the tract.

Question 25

What type of muscle is the GI tract mainly composed of ?

Answer 25

It is mainly composed of smooth muscle tissue but also striated muscle because of the voluntary capacity.

Question 26

What is it that connects the laryngopharynx to the stomach ?

Answer 26

The oesophagus.

Question 27

Two key processes important in movement

Answer 27

Peristalsis, segmentation.

Question 28

Peristalsis

Answer 28

Concerned with propulsion of food along the GI tract.

Relies on the longitudinal muscle relaxing and contracting.

Question 29

Segmentation

Answer 29

Occurs largely in the small intestine to facilitate mixing of food.
Relies on the circular muscle surrounding the GI tract contracting and relaxing.

Question 30

Potential barriers a drug has to cross depending on the mode of delivery

Answer 30

Buccal - through the cheek layer.

Sublingual - under the tongue.

Question 31

Why do the drugs need to dissolve across the wall of the cheek ?

Answer 31

In order to cross the epithelial barrier to enter the bloodstream.

Question 32

Why is there a greater bioavailability for this type of drug delivery ?

Answer 32

This is because the drug enters the blood circulation directly without the need to go the through the digestive system and therefore avoiding the first pass metabolism - where there is a loss of drug during absorption via the gut walls.

Question 33

What us this type of delivery good for ?

Answer 33

If the there is a need for rapid action, e.g. the class of drug that targets angina.

Question 34

Issues concerning the make up of this type of drug

Answer 34

Solubility of the drug in saliva.
Passive diffusion - only small lipophilic drugs will be well absorbed.
The potential barriers to absorption, e.g. SA in the mouth is limited so the drug must passively diffuse through the epithelium and the basement to enter the blood stream where there is a fish blood supply and so fast onset of action, assuming drug delivery was successful.

Question 35

Considerations of buccal administration

Answer 35

Drugs must dissolve in saliva - hydrophobicity of the drug must be considered.
Swallowing reflex - retention in the mouth is important because the drug has to stay in the mouth for a certain period of time.
SA in the mouth is limited.
The drug has to diffuse across lipophilic cell membranes and the hydrophilic interior of the cell.
Enzymatic barriers exist which can break down small peptides or proteins which limits the transport across the epithelium in the cheek.

Question 36

Challenges for buccal delivery

Answer 36

Chemical or physical barriers.
The drug (dose) must be kept in place for absorption and excess saliva could disrupt this.
The drug’s hydrophobicity/hydrophilicity.
SA of the mouth.
Taste of the drug needs to be bland - could affect retention.
Must be a non-irritant to teeth and mouth.

Question 37

Key oral/dental problems

Answer 37

Dry mouth - xerostomia, oral ulcers, oral thrush.

Question 38

Dry Mouth

Answer 38

Can lead to ulceration and tooth decay.
Affects digestion and drug absorption.
Saliva preparations (lozenge/spray/gel) can be used to combat this side effect.

Question 39

Oral ulcers

Answer 39

Vary in terms of severity - smaller ulcers clear up without any treatment.
In severe cases, the patient may require corticosteroids and anti-inflammatories and an anti-microbial mouthwash to prevent infection.
There are OTC treatments but sometimes patients may require prescriptions.

Question 40

Oral thrush

Answer 40

Yeast infection-caused by the over use of antibiotics, poor immune system, underlying disease, smoking, diet, dentures.
Treatment aimed at reducing fungal infection using an anti-fungal gel e.g. miconazole, nystatin.

Question 41

Certain medications can lead to…

Answer 41

…dental issues and may result in tooth decay e.g. antacids, pain medications, antihistamines.

Question 42

Inhalers

Answer 42

Those who require the frequent use of inhalers may have dental problems.
Inhalers contain an ingredient, beta-adrenergic agonist which is slightly acidic and so is harmful so tooth enamel overtime.

Question 43

Advice for dental hygiene

Answer 43

Drink plenty water.
Brush teeth twice a day and get regular dental checkups.
Use a moisturising mouth spray.
Reduce/give up smoking.
Reduce intake of caffeinated or dehydrating drinks.
Use a hydrating mouth wash.