Changes

==Introduction==

==Introduction==

Nerves of the peripheral nervous system (PNS) are composed of numerous bundles of nerve fibers that are surrounded by connective tissue. This connective tissue also contains a specific layer that is specialised to neurons; the [[PNS Structure - Anatomy & Physiology#Structure|''peri-neurium'']]. The outer layer of this connective tissue is called the [[PNS Structure - Anatomy & Physiology#Structure|''epineurium'']] and it surrounds both the perineurium and the nerve itself. Individual neurons found within each bundle are surrounded by the [[PNS Structure - Anatomy & Physiology#Structure|''endoneurium'']].

Nerves of the peripheral nervous system (PNS) are composed of numerous bundles of nerve fibers that are surrounded by connective tissue. This connective tissue also contains a specific layer that is specialised to neurons; the [[PNS Structure - Anatomy & Physiology#Structure|''peri-neurium'']]. The outer layer of this connective tissue is called the [[PNS Structure - Anatomy & Physiology#Structure|''epineurium'']] and it surrounds both the perineurium and the nerve itself. Individual neurons found within each bundle are surrounded by the [[PNS Structure - Anatomy & Physiology#Structure|''endoneurium'']].

Within the nerve bundle itself, the individual nerve fibres have a characteristic 'wavy' appearance. There are also a number of nuclei visible within the image and these are nuclei belonging to Schwann cells or to cells found within the endoneurium. At this magnification it is possible to identify some elements of the nerves themselves. In some of the fibres it is possible to visualise a faint central tubular structure which represents the axon of the nerve. (One is visible in the 6th nerve down from the top of the image). The lighter brown element of each nerve represents the myelin sheath whilst the darker brown lines surrounding both side of each nerve represents the thin cytoplasm of the Schwann cell (neurilemma cell).

Within the nerve bundle itself, the individual nerve fibres have a characteristic 'wavy' appearance. There are also a number of nuclei visible within the image and these are nuclei belonging to Schwann cells or to cells found within the endoneurium. At this magnification it is possible to identify some elements of the nerves themselves. In some of the fibres it is possible to visualise a faint central tubular structure which represents the axon of the nerve. (One is visible in the 6th nerve down from the top of the image). The lighter brown element of each nerve represents the myelin sheath whilst the darker brown lines surrounding both side of each nerve represents the thin cytoplasm of the Schwann cell (neurilemma cell).

Another clearly visible element of the individual nerves is indicated on the image by black arrows. These arrows indicate positions of [[PNSschStructure - Anatomy & Physiology#Schwann Cell|''nodes of Ranvier'']] and represents the point at which two Schwann cells meet along the length of the axon. The histologic appearance of a node is as a constriction of the neurilemma.

Another clearly visible element of the individual nerves is indicated on the image by black arrows. These arrows indicate positions of [[PNS Structure - Anatomy & Physiology#Schwann Cell|''nodes of Ranvier'']] and represents the point at which two Schwann cells meet along the length of the axon. The histologic appearance of a node is as a constriction of the neurilemma.

===Autonomic Ganglion Cross-section===

===Autonomic Ganglion Cross-section===

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[[Category:A&P Done]]

[[Category:A&P Done]]

[[Category:Nervous System - Anatomy & Physiology]]

[[Category:Nervous System - Anatomy & Physiology]]

[[Category:Histology]]

[[Category:Histology]]