Learning Modules - Medical Gross Anatomy
Autonomics of the Thorax - Page 6 of 12


The sympathetic innervation of the lungs originates from the thoracic portion (T1-T4 or T5) of the spinal cord. The presynaptic fibers pass through white rami communicantes to reach the sympathetic trunk, where they synapse in the upper thoracic chain ganglia. The postsynaptic fibers then pass via slender thoracic visceral nerves into the pulmonary plexus to innervate the vasculature of the lungs, while epinephrine released from the suprarenal cortex acts upon the bronchial smooth muscle. Stimulation of the sympathetic nervous system acts to VASOCONSTRICT and BRONCHODILATE.

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