Lecture 1- Normal Swallow

Question 1

Define Dysphagia

Answer 1

a DISORDER or difficulty with swallowing

It is NOT a disease or primary medical diagnosis itself, rather a SYMPTOM of an underlying disease process.

Question 2

How many muscles are involved in the swallowing process?

Answer 2

26 pairs of muscles

Question 3

How many cranial nerves are involved in the swallowing process?

Answer 3

6 cranial nerves

Question 4

Name the 5 stages of the swallow and which are voluntary as opposed to involuntary.

Answer 4

1. Oral Anticipatory
2. Oral Preparation
3. Oral Transit
4. Pharyngeal stage
5. Oesophageal stage

The oral stage is under voluntary control – can be interrupted at any time. The pharyngeal & oesophageal stages are involuntary.


Question 5

Describe the primary role of the Anticipatory Stage

Answer 5

Sensory acknowledgement that food is present leads to an appropriate or expected response (e.g. mouth opening, judging how much to put in your mouth, using smell, judging temperature).

Pre-oral motor, cognitive, psychosocial & somatoesthetic elements

Question 6

Describe the primary role of the Oral Preparatory Stage

Answer 6

Preparation of food and fluid for oral transit & initiation of the pharyngeal swallow.

Question 7

What happens during the Oral Preparatory stage

Answer 7

􏰀- The mouth & lips open to accept the bolus.
- The tongue forms a ‘groove’ to accept the bolus.
- The lips seal around the bolus to prevent anterior spillage of the
bolus (1st of 4 valves; part of the pressure system).
- Tension in the lips & cheeks keeps the food in the correct place.
- Food & liquid in the mouth stimulates taste, temperature, &
pressure (touch) receptors.
- Saliva is produced by as the salivary glands are activated.

Question 8

In the Oral Preparatory stage what occurs for solids to be swallowed?

Answer 8

Coordinated action of the tongue & jaw moves the bolus onto the teeth for mastication (rotatory chewing to grind & crush the bolus by the teeth).
􏰀 Buccinator press – cheek tension flattens the cheeks &
keeps the bolus within the “dental vault”.

Question 9

Define Glossopalatal seal

Answer 9

• Tongue & amp; soft palate contact seals the oral cavity, containing the bolus within the mouth.
• Prevents premature spillage of the liquid posteriorly into the pharynx before the swallow is triggered - holds the bolus in your mouth until you’re ready to swallow.
  􏰀- The glossopalatal seal is more important for liquids than solids.

Question 10

Define Buccinator press

Answer 10

When cheek tension flattens the cheeks &

keeps the bolus within the “dental vault”.

Question 11

Define Mastication

Answer 11

To chew

Question 12

Define Velopharyngeal seal

Answer 12

Sphincter like action involving the velum, lateral and posterior pharyngeal wall which prevents nasal regurgitation.
This seal also contributes to the pressure system.

Question 13

Define Pharyngeal constriction

Answer 13

Peristaltic-like movement, squeezing the bolus through the pharynx towards the oesophagus.

Question 14

Define Epiglottic deflection

Answer 14

The epiglottis tilts backwards to deflect the bolus away from the laryngeal vestibule or inlet.
Mechanisms:
- Hyolaryngeal excursion (most important) – upward & forward movement of the hyoid & larynx pulls the base from under the epiglottis, causing it to tilt backwards.
-Epiglottis - Biomechanical folding/ spring.
- Superior pressure from BOT (minor role).

Question 15

Define BOT to PPW approximation

Answer 15

The base of tongue retracts and the posterior pharyngeal wall moves forwards (BOT to PPW approximation) – This applies positive pressure on the bolus – moving it rapidly through the pharynx into the oesophagus.

Question 16

Define Airway Protection

Answer 16

Airway protection: Ensures food / drink does not enter the larynx, trachea or lungs (i.e. preventing penetration & aspiration).

Question 17

Define Glottal closure

Answer 17

Valving of the laryngeal vestibule involves:
􏰀- Closure or adduction of the true vocal cords
- Closure of the false vocal folds over the true vocal folds

Question 18

Define Lip seal

Answer 18

Lip seal & cheek tone help control & manipulate the liquid bolus & prevent anterior spillage from front (or corners) of the mouth.

Question 19

Describe the primary role of the Oral Transit Stage

Answer 19

Posterior propulsion of the bolus from the oral cavity into the pharynx following bolus preparation.

Question 20

What happens during the Oral Transit stage

Answer 20

1. Tongue tip elevates & presses against the hard palate occluding the oral cavity.
2. Tongue dorsum & cheek tension contain the bolus laterally.
3. Posterior tongue drops to open the back of the oral cavity.
4. Tongue-palate contact expands from front to back – squeezing the bolus back along the palate & into the oropharynx, through the faucial arches.
5. The pharyngeal stage or reflexive swallow is triggered.

Question 21

Describe the 2 primary roles of the Pharyngeal Stage

Answer 21

1) Food passage: Propels the bolus through the pharynx, through the UES, to the oesophagus.
2) Airway protection: Ensures food / drink does not enter the larynx, trachea or lungs (i.e. preventing penetration & aspiration).

Question 22

What happens during the Pharyngeal stage

Answer 22

1. Bolus arrives in the valleculae
2. The bolus is propelled through the lateral channels (pyriform sinuses) of the pharynx into the oesophagus.
3. Bolus is transferred back into the pharynx & pharyngeal stage is triggered the velopharyngeal seal prevents nasal regurgitation.
4. The base of tongue retracts and the posterior pharyngeal wall moves forwards (BOT to PPW approximation)
5. The larynx is drawn upwards & forwards (hyolaryngeal excursion)
6. Constrictor muscles sequentially shorten & narrow the pharynx (pharyngeal constriction)
7. The bolus is then drawn through the UES into the oesophagus.
8. After the tail of the bolus passes through the UES it closes tightly shut, preventing reflux.
9. The hyoid bone then returns to its resting position; the airway reopens.

Question 23

Describe the primary role of the Oesophageal Stage

Answer 23

To move the bolus from the UES to the stomach for digestion.

Question 24

What happens during the Oesophageal stage?

Answer 24

• Relative ‘simple’ phase – peristaltic wave of contraction. Begins as the bolus passes through the UES.
• Oesophageal peristalsis occurs every 2 to 4 seconds - moves bolus in waves along the length of the oesophagus to the lower oesophageal sphincter (LES).
• Takes 6-20 seconds.