INNERVATION OF ALVEOLAR WALLS IN THE HUMAN-LUNG - AN ELECTRON-MICROSCOPIC STUDY

  • 1 January 1980
    • journal article
    • research article
    • Vol. 131  (DEC) , 683-692
Abstract
In an EM study of the human lung, unmyelinated nerve fibers, probably sensory type, were found in the alveolar wall. Lung tissue obtained by thoracotomy was examined from 16 patients, and sections from 50 blocks obtained from the periphery of the lung were studied. Where the tissue came from lobectomy or pneumonectomy specimens, care was taken to sample macroscopically normal areas. Nerve fibers were studied only in alveolar areas. To minimize the possibility that nerve fibers seen were innervating bronchioles, any nerve fibers found < 200 .mu.m from ciliated epithelium were not examined. Unmyelinated nerve fibers within the alveolar wall and mainly surrounded by collagen were found in 1 block of tissue from each of 3 cases. Lung tissue was histologically normal in 3 of the cases and in the 3rd, although the alveolar wall was normal, the alveoli contained macrophages. Since the majority of the vesicles seen within the axons were agranular it was apparent that the nerve fibers were sensory in origin. These nerve fibers in the human lung may be associated with juxta-capillary receptors which have been identified on physiological grounds in animals.