Morphometric Comparison between Human and Rat Abducens and Oculomotor Nerves
| Autor: | A. Bardosi, Josephine Shallo, Claus Schäfer, Hermann Mühlendyck |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Adult
Histology genetic structures 040301 veterinary sciences Extraocular muscles Nerve Fibers Myelinated 0403 veterinary science Nervus oculomotorius 03 medical and health sciences Nerve Fibers Abducens Nerve Oculomotor Nerve Sural Nerve Animals Humans Medicine Nervus Abducens 0303 health sciences business.industry Oculomotor nerve Eye movement Rats Inbred Strains 04 agricultural and veterinary sciences Anatomy Rats medicine.anatomical_structure 030301 anatomy & morphology Peripheral nervous system business |
| Zdroj: | Cells Tissues Organs. 138:24-31 |
| ISSN: | 1422-6421 1422-6405 |
| DOI: | 10.1159/000146916 |
| Popis: | A morphologic and morphometric comparison between normal human and rat extraocular muscle nerves was performed using a computer-assisted method to obtain scatter diagrams of relative sheath thickness (g ratio = quotient axon diameter/fiber diameter). Human and rat extraocular muscle nerves (nervus abducens and ramus medialis n. oculomotorii) were excised immediately before the nerve branching at the entering point into the muscle. There was no difference in the absolute number of myelinated fibers between the oculomotor and abducens nerves in both species. The distribution of myelinated fibers was classified according to their g ratios into a two-stage density cluster analysis. Two main populations of nerve fibers for human oculomotor and rat oculomotor and abducens nerves and three main populations for human abducens nerve were differentiated morphometrically and mathematically, differing in their relative sheath thicknesses. There are distinct differences between scatter diagrams of human and rat extraocular muscle nerves, in correlation with the basically different oculomotor functions of these two species. The morphometric differences between human and rat extraocular muscle nerves suggest a difference in the myelination process and the presence of functionally different nerve fibers strongly indicated by the populations and subpopulations of myelinating nerve fibers peculiar to extraocular muscle. The existence of more than two different types of myelinated fibers in the human nerves implies that the traditional classification based on fiber caliber must be reviewed and a comparison of different classes of nerve and muscle fibers should be performed. |
| Databáze: | OpenAIRE |
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