The connective tissue coverings of leech peripheral nerves: anatomical evidence for the absence of cerebrospinal fluid in the leech

J. M. Wilkinson, R. E. Coggeshall

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The central nervous system of Hirudo medicinalis is contained within a blood vessel, the ventral longitudinal sinus, but the nervous system is separated from the blood by the visceral endothelium. The visceral endothelium possesses many pinocytotic vesicles and basal infoldings and thus appears active whereas the parietal endothelium appears inactive. The junction between the visceral and parietal endothelia is abrupt. Peripheral nerves in this animal, as in vertebrates, are covered by endoneurium, perineurium, and epineurium. The endoneurium is continuous with the fibrous tissue of the segmentae ganglia. The perineurium, endoneurium, consisting of a single layer of flattened cells that surrounds the peripheral nerve like a sleeve, is not continuous with the endothelium of the ventral sinus, but is separated from it by 5-10 microns. Therefore, at the point where the peripheral nerve joins the segmental ganglion, the extracellular spaces of the central nervous system, the peripheral nervous system, and the body wall are all confluent. Thus, there are only two compartments of the extracellular space in the leech: the blood, which is enclosed by the endothelia of the coelomic sinuses, and the extracellular fluid of the body, which includes the extracellular fluid of the nervous system. There seems to be no equivalent of cerebrospinal fluid in the gnathobdellid leech.

Original languageEnglish (US)
Pages (from-to)381-389
Number of pages9
JournalJournal of Comparative Neurology
Volume170
Issue number3
StatePublished - 1976

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Leeches
Peripheral Nerves
Connective Tissue
Cerebrospinal Fluid
Endothelium
Extracellular Fluid
Extracellular Space
Ganglia
Nervous System
Central Nervous System
Hirudo medicinalis
Peripheral Nervous System
Blood Vessels
Vertebrates

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

The connective tissue coverings of leech peripheral nerves : anatomical evidence for the absence of cerebrospinal fluid in the leech. / Wilkinson, J. M.; Coggeshall, R. E.

In: Journal of Comparative Neurology, Vol. 170, No. 3, 1976, p. 381-389.

Research output: Contribution to journalArticle

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