Describe the control of gastrointestinal motility, including sphincter function
Swallowing is divided into three phases:
- Oral Phase
- Food is pushed against hard palate by tongue
- Pharyngeal Phase
Coordinated by medulla.
- Closure of nasopharynx
- Adduction of vocal cords
- Hyoid elevation and deflection of epiglottis
- Pharyngeal contraction
Propels food bolus towards oesophagus
- Oesophageal phase
- Closure of UoS
Resting barrier pressure 100mmHg.
- Relaxation of LoS
Resting barrier pressure 20mmHg, which is a balance between:
- LoS pressure (30mmHg)
- Antral pressure (10mmHg)
- Oesophageal peristalsis
Impairment of any of these processes increases risk of aspiration:
Reduced cough reflex.
- Muscular weakness
- Impaired medullary coordination
- Chambers D, Huang C, Matthews G. Basic Physiology for Anaesthetists. Cambridge University Press. 2015.