Swallowing

Question 1

what are the stages of swallowing?

Answer 1

• food into front of mouth (if no -spit out)
• stage I transport (to posterior teeth) (if no- mastication)
• stage II transport to back of tongue “bolus” formation (bolus formation continues)
• swallow

Question 2

what are the frequencies of swallowing?

Answer 2

• 500-2500 per day
• 25% while eating
• 65% when awake
• 10% when asleep

Question 3

what are the phases of a command swallow?

Answer 3

1. Oral
2. Pharyngeal
3. Oesophageal

Question 4

what closes over to seal the airway?

Answer 4

epiglottis

Question 5

Describe the oral phase of the command swallow.

Answer 5

• tongue : stabilised and raised to hard palate
• Soft palate: raised, naso-pharyngeal seal
• lower airway protected: stop breathing and larynx raised

Question 6

Describe the pharyngeal phase of the command swallow.

Answer 6

• tongue : backwards
• pharyngeal constrictors : squeeze
• upper oesophageal “sphincter” : cricopharynxgeus muscle opens
• lower airway protected: epiglottis -down , vocal cords -close

Question 7

Describe the oesophageal phase of the command swallow.

Answer 7

• primary peristalsis -moves bolus
• lower oesophageal “sphincter” opens
• secondary peristalsis - reflex response to debris and cleansing (more for solids than liquids)
• sphincters close
• respiratory system - airway re-opens and breathing resumes

Question 8

what is peristalsis?

Answer 8

-Unidirectional wave of muscle contraction in a tubular organ i.e oesophagus

Question 9

what is the difference between a bolus going through the oesophagus and intestine?

Answer 9

In the oesophagus there is a wave of contraction behind the bolus but no relaxation infront unlike the intestine where there is a contraction and relaxation wave

Question 10

what is the preparatory phase of swallowing solid food?

Answer 10

• food broken down (mastication)
• stage II transport
• food accumulates on posterior (pharyngeal surface) of the tongue

Question 11

what is the difference between swallowing solid vs liquid substances?

Answer 11

• Liquid - swallowed from mouth and has distinct oral phase

- Solid- swallowed from mouth and/or oro-pharynx and has an oro-pharyngeal phase

Question 12

what is the difference between adult and infant swallowing?

Answer 12

• adult- teeth together, jaw/tongue stabilised by jaw closing muscles , tip of tongue stable behind incisors
• Infants -gums apart ,jaw/tongue stablised by facial muscles , tongue thrust

Question 13

what is the muscle control of swallowing?

Answer 13

• skeletal muscle :upper 1/3 - motor neurone control

- rest : smooth muscle -autonomic control

Question 14

what is the pathway of swallowing?

Answer 14

• higher centres e.g. cerebral cortex
• swallowing centre in brainstem
• swallowing muscle- motor neurones

Question 15

what are the characteristics of reflex swallowing?

Answer 15

• mechanoreceptive - back of mouth/pharynx
• water sensitive -epiglottis
• chemoreceptive- mouth

Question 16

what is the stimuli of gag reflex?

Answer 16

-mechanical at the back of the mouth/ oropharynx i.e rarely food but dental procedures (impressions)

Question 17

what determines whether the stimuli is for swallowing or gagging?

Answer 17

CNS-which produces one response and supresses the other