Cells of the Nervous System and Neurons lecture 12

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