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HN 285

STRUCTURES INVOLVED IN SWALLOWING

SOFT PALATE
HARD
PALATE

LIPS TONGUE
PHARYNGEAL
MANDIBLE CONSTRICTOR
MUSCLES

MYLOHOID
MUSCLE HYOID
BONE

EPIGLOTTIS
THY ROID
SKELETAL CARTILAGE
MUSCLES:
CRANIAL NN LARYNX 1 CRICO-PHARYNGEAL
V, VII, X, XII: INLET SPHINCTER
CENTRAL CRICOID
PATTERN CARTILAGE CERVICAL OESOPHAGUS
GENERATOR

1/3

FOR SIGNIFICANCE 1/3
OF "OESOPHAGEAL
THIRDS", SEE SI 145 THORACIC
OESOPHAGU
S

SMOOTH
MUSCLE: POSITION OF
PERISTALSIS 1/3 STOMACH
ORGANIZED ABDOMINAL
BY ENTERIC INFERIOR OESOPHAGU
AUTONOMIC SPHINCTER S
NERVE PLEXUS
IN GUT
WALL;
OPERATES
INDEPENDENT
OF CNS, BUT
MODULATED
BY VAGUS NERVES (CR. N. X - PARASYMPATHETIC COMPONENT), &
SYMPATHETIC OUTFLOW.

NOTE: CHEWED FOOD, OR LIQUID, MUST BE EJECTED BACKWARDS INTO THE ORO-PHARYNX: THIS
IS ACCOMPLISHED BY THE TONGUE; THE LIPS & ANTERIOR TONGUE PREVENT ESCAPE
THROUGH MOUTH; THE BUCCINATOR MM. AGAINST THE OCCLUDED (CLENCHED) TEETH
KEEP THE VESTIBULES EMPTY. RAISING & TENSING THE SOFT PALATE PREVENTS ENTRY
INTO THE NASO-PHARYNX & NASAL CAVITY. THE LARYNGEAL INLET IS CLOSED
(PARTICIPATION OF THE EPIGLOTTIS IS NOT ESSENTIAL): PERISTALSIS BEGINS IN THE
PHARYNGEAL CONSTRICTORS & CONTINUES DOWN THE OESOPHAGUS. THE SPHINCTERS
MUST RELAX.