Flashcards in Lecture 6 - Nerves Deck (56)
What are the major types of glial cells in the PNS?
1. Schwann Cells
2. Satellite Cells
*oligodendrocytes and schwann cells have similar functions
Purpose of oligodendrocytes?
Form the myelin sheath in the CNS
Purpose of schwann cells?
Form the myelin sheath in the PNS
How can impulses down the axons travel faster?
Myelin sheath insulates parts of the axon and makes the impulse "jump" from node to node (of ranvier)
What is the primary component of myelin?
What glial cell myelinates parts of several axons in the CNS?
Where are schwann cells located and how are they different from oligodendrocytes?
1. In the PNS
2. Multiple schwann cells wrap themselves around a single axon, where as oligodendrocytes can myelinate several axons at the same tie
Compare the location of white matter to grey matter in the cranium
1. White matter is located more centrally
2. Grey matter is located near the cortex
What is the main component of grey matter?
1. Neuronal cell bodies
Compare the location of white matter to grey matter in the spinal cord
1. White matter is located around the outside of the spinal cord
2. Grey matter makes up the middle of the spinal cord
What is the most abundant glial cell in the CNS?
Features of astrocytes
1. Very little cytoplasm
2. Elongated or oval nuclei
3. Numerous cytoplasic processes (star shaped = astro)
4. Part of the BBB
Main functions of astrocytes?
1. Regulate extracellular ion concentration
2. Metabolic support for neurons
3. Modulate Synaptic transmission
4. Nervous system repair
*"Helps Mets Modulate Nerves"*
What are the perivascular feet and what are their function?
1. Processes of the astrocyte that attach to blood supply
2. Helps maintain the BBB
3. Helps regulate local CNS blood flow
What cells line the Ventricles and Central Canal?
What are ependymal cells?
*similar to epithelial cells
Features of ependymal cells
1. Ciliated - move fluid through the NS
2. Have branches that go to parynchyma of the spinal cord
3. Capable of division and migration into neuropil to form new neurons
How to tell ependymal cells apart from epithelial cells?
Ependymal cells do not have a basal lamina or basment membrane to anchor to
Functions of the microglia
4. Clear away dying cells and help repair neuronal damage
*evenly distributed in grey and white matter*
What are "nerves" composed of?
Where are ethe cell bodies of the axons w/in a peripheral nerve located?
*ganglia are in the PNS
Features of the Dorsal Root Ganglion
1. Contains Sensory (afferent) neurons
2. Have neuronal cell bodies - unipolar neurons
Features of satelite cells
1. Restricted to ganglia
2. Cover and support large neuronal cell bodies
3. Located in PNS
What is in a peripheral nerve?
1. Myelinated Axon
2. Unmyelinated Axon
3. Schwann Cell
4. Connective tissue
What layer covers the entire nerve?