Studied by 16 people
what are glial cells?
they are support neuronal survival and function. they as abundant as neurons
what are the glial cells in the CNS
Oligodendrocytes
Astrocytes
Microglia
what are the glial cells in the PNS
Satellite Cells
Schwann Cells
what are the oligodendrocytes are what do they do?
Manufacture and maintain myelin in CNS
One oligodendrocyte can wrap many axons with myelin
Axons can have different segments wrapped by different oligodendrocytes
what are astrocytes and what do they do ?
Most numerous glial cell in CNS
Processes make contact with neurons and capillaries
Regulate extracellular ion concentrations and the Blood Brain Barrier (BBB)
what are the microglia and what do they do
Phagocytic cells found throughout CNS.
Defense and Garbage men for the CNS
what are the Schwann cells and what do they do?
Generate myelin sheaths in PNS
Usually one Schwann cell wraps part of one axon
(Axons covered by contiguous Schwann cells)
what are the satellite cells and what do they do?
Arrange around neuronal cell bodies outside of CNS (in ganglia)
Regulate exchange of nutrients and waste. (Astrocytes of PNS)
The PNS can regenerate
The CNS cannot regenerate
True
How is information passed along a neuron?
Action Potential
what are some components of action potential
it is based on changes in membrane charge.
the charge is based on the movement of ions
measured in voltage and current
how is voltage change measured
Differing ion concentrations at rest ( Sodium (Na+) and Potassium (K+))
what is resting membrane potential
The membrane charge at rest before an Action Potential occurs
what is the number that the neuron is at rest
-70mV
Establishing resting membrane Potential is regulated mainly by
Potassium (K+)
K+ channels are slightly leaky it is diffuse
diffuse down their steep concentration gradient (out of the cell)
what is the membrane potential
Inside of cell is negative compared to outside only at the membrane
when is the rest potential established when movement of
K+ out equal K+ in
the sodium attracted to interior of cell
More Na+ outside cell
To maintaining the membrane potential at -70mV
the Na+- K+ Pump (restores order)
3 Na+ out!!
2 K+ in
