Page 131 - Edited - Webster HEAD AND NECK - part 2-Merge PDF

NERVE COMPONENTS LOCATION OF CELL PERIPHERAL FUNCTION
BODIES OF FIBRES DISTRIBUTION

X Vagus (cont'd) Efferent (motor)
i) Parasympathetic 1. Presynaptic axons Cardiac muscle, SA and Control of heart beat ("cardiac
from cell bodies in brainstem AV nodes. Smooth muscle in: depression")
2. Postsynaptic cell GI tract to splenic flexure; Modulation of GI motility.
bodies in walls of trachea, bronchi, etc. Modulation of diameter of airways
viscera and thoraco- Exocrine glands in pharynx,
abdominal plexuses. larynx and upper oesophagus Secretomotor

and gut.

ii) Somatic Brainstem Skeletal muscle of lower Swallowing and vomiting
pharynx, soft palate (except (Modulation of phonation - pharynx;
tensor), upper oesophagus, - see also IX)
2
and of Larynx - see XI

XI Accessory HN 319
Cranial Efferent (motor) Brainstem Skeletal muscle of larynx, soft Phonation; protection of airways
somatic palate, and lower pharynx
(distributed with vagus) 2

Spinal Efferent (motor) Upper four cervical Trapezius and sterno- Shoulder and arm movements;
somatic segments of spinal cord cleidomastoid head movements

XII Hypoglossal Efferent (motor) Brainstem Intrinsic muscles of tongue, Chewing, speech articulation,
(Greek "below somatic and hyoglossus, genioglossus, swallowing
the tongue") styloglossus (i.e. all tongue
muscles except palatoglossus)

K.E.W.

2 Note: It is important to remember that although the motor innervation of the larynx (phonation, protection of airways) arises from the brain as the cranial root of the accessory nerve, it distributes peripherally with the vagus - in its superior
laryngeal and especially recurrent laryngeal branches.

cranerv2 5