ABSTRACT
The autonomic nervous system innervates the lung with parasympathetic fibers from the vagus nerve and sympathetic fibers from the upper thoracic and cervical ganglia (see Table 1). Afferent nerves are part of the cough reflex and provide input about lung stretch and inflation to the respiratory control centers. (See Chaps. 2 and 5.) Efferent nerves influence the smooth muscle tone of the airways and blood vessels, altering regional ventilation and
Nerve Functions
Parasympathetic Vagus nerve (cranial Afferents Irritant (cough) recep nerve X) tors, stretch (infla
tion) receptors, C fi bers (parenchymal tissue distortion)
Efferents Airway constriction, in creased glandular se cretion, dilatation of pulmonary vascula ture
Sympathetic Preganglionic from spi Efferents Airway relaxation, inhi nal cord of T1 to T6 bition of glandular to sympathetic secretion, constric trunks tion of pulmonary
Postganglionic fibers vasculature from upper four to five paravertebral ganglia to pulmo nary plexus
Skeletal muscle innervation
Muscle Nerve Nerve roots Function
Diaphragm Phrenic nerve C 3-5 Inspiration Stemocleidomastoids Cervical and cranial Cranial nerve XI Inspiration
nerves C 1-2 Scalenes Cervical nerves C 4-6 Inspiration Intercostal s Thoracic spinal nerves T l-12 Inspiration and
expiration Pectoralis Thoracic spinal nerves C 6-8 Expiration Transversus thoracis Thoracic spinal nerves T 2-6 Expiration Rectus abdominis Thoracoabdominal T 6-12 Expiration
branches External and internal Thoracoabdominal T 6-12 Expiration
abdominal obliques branches of thoracic spinal nerves
Transversus abdominis Thoracoabdominal T 6-12 Expiration branches
perfusion. This activity can contribute to bronchospasm. Efferent autonomic activity can also modify the secretion of mucus and solute from secretory glands.
