IC1 Histology of the PNS Flashcards
1
Q
The PNS is composed of
A
- Neuron processes and cell bodies located outside the CNS
- Neuroglial cells (Schwann cells and Satellite cells - support cells of Ganglia)
- Nerve endings
2
Q
Describe the structure of a peripheral nerve
A
- A peripheral nerve comprises bundles (fascicles) of nerve fibers / axons that are surrounded by myelin sheaths or Schwann cells
- And are invested with three connective tissue elements - epineurium, perineurium and endoneurium
3
Q
Epineurium is the _____
A
Connective tissue surrounding the entire nerve
4
Q
Perineurium is the _____
A
Layer of dense connective tissue around each fascicle of nerve fibers
5
Q
Endoneurium is the _____
A
- Thin, reticular layer that surrounds each individual nerve fiber and contains Schwann cells
- Endoneurium is made up of myelin sheaths made by Schwann cells
6
Q
What is the function of Schwann cells?
A
Form myelin sheath around PNS nerve fibers / myelinated axons
Like Oligodendrocytes in CNS
7
Q
What is the difference between myelin-producing cells in the CNS vs PNS?
A
Oligodendrocytes (CNS)
Individual oligodendrocytes myelinate portions of several axons
Schwann cells (PNS)
Individual Schwann cells myelinate portions of only a single axon
8
Q
What are ganglia / dorsal root ganglion?
A
- Encapsulated collections of neuron cell bodies, located outside the CNS
- Contain satellite cells and connective tissue elements along with neurons
9
Q
What is the function of satellite cells?
A
- Are amphicytes that form a capsule of cells around neuron cell bodies in the peripheral ganglia
- Provides support for the neurons
