Neurons

How do neurons find their target?

Axons of neurons send out growth cones that contain actin microfilaments and microtubules that assemble and dis-assemble, extending membrane at the tip of the axon until it “finds” its target tissue

the synapse between the neuron and target must be _______ or it will be _____

used, lost

What is brain growth due to

an increase in the size of the axons and dendrites protruding from cells, not an increase in number of cells

describe plasticity

the ability for synapses to re-arrange in response to variations in electrical activity, critical for learning

Schwann cell

wrap around one section of afferent or efferent neuron axon and form insulating myelin sheaths; assist with neuronal axon damage “clean up and repair”

oligodendrocyte

can wrap around two interneuron axons to form insulating myelin sheath

what do GAP junctions do

allow nutrients to flow between layers of myelin

what are the two types of glial cells in the PNS

Schwann cells and satellite cells

satellite cells

form supportive capsules around neurons in ganglia

ganglion

clusters of neuron cell bodies in the PNS, appear as knots along a nerve

nuclei

clusters of neuron cell bodies in the CNS

4 types of glial cells in the CNS

oligodendrocytes, microglia, ependymal cells, astrocytes

microglia

specialized immune cells

ependymal cells

one source of neural stem cells/form barriers between fluid filled compartments

astrocyte

source of stem cells, communicate with each other through GAP junctions and provide nutrients to neurons

what type of glial cell makes up 50% of all glial cells

astrocytes

what cells are important for the BBB

astrocytes