A&P - Chapter 18 (Part 5) Flashcards
Nerves
Bundles of peripheral never fibres held together by several layers of connective tissue
Mixed nerves
Contain sensory and motor neurons
What are nerves normally covered by?
Myelin sheath
How does myelin appear in colour?
White
White matter
Tissue composed primarily of myelinated axons
Gray matter
Tissue composed primarily of cell bodies and unmyelinated fibres
Nerve coverings
Individual axons, fascicles and nerves are surrounded by thin layers of fibrous connective tissues that have specific names based on their location
What are 3 examples of nerve coverings?
- Endoneurium
- Perineurium
- Epineurium
Endoneurium
Tissues that surrounds individual nerve fibres/axons
- within/inside
Perineurium
Tissue that surrounds individual fascicles
- around
Fascicles
Bindles of nerve fibres/axons
Epineurium
Tissues that surround numerous fascicles and blood vessels to form a complete nerve
- upon
What is another word for axon?
Nerve fibre
What is another word for bundle of axons?
Fascicle
What is another word for bundle of fascicles?
Nerves
What does the brain only have in terms of signals?
Tracts
- no nerves
What do tracts not have?
Connective tissue coverings
Where do nerves need to have a coat?
PNS
Where do nerves not need to have a coat?
CNS
What does a coat act as?
Protection
White matter in the PNS?
Myelinated nerves
White matter in the CNS?
Myelinated tracts
Gray matter
Unmyelinated cell bodies and nerve fibres
Where is gray matter found in the PNS?
Ganglia
Where is gray matter found in the CNS?
Nuclei
What is another word for a bundle of axons in the CNS?
A tract
What are mature neurons incapable of?
Cell division
What are neurons limited in?
Repair
What happens if the damage is not extensive to the nerve?
The cell body and neurilemma are intact and scarring does not occur
- fibres then can be repaired
