1. found in the peripheral nervous system (outside the brain and spinal cord)
2. Aid in the regeneration of damaged nerve fibers
3. Lay down the Myelin Sheath
Oligodendroglia = glial cells
1. found in the CNS (brain)
2. involved in memory
3. lay down the myelin sheath
Dendrites
specialized for excitability
Cell body
controls the metabolism of the cell
axon
speicalized for conduction (transporting info)
myelin sheath
a covering over the axon that aids in the conduction of nerve impluses
nodes of ranvier
interruptions of the myelin sheath
axon hillock
enlarged region where the axon emerges
axon terminal
an enlargement at the end of the axon aka the terminal bouton or terminal button
resting potential
recorded from the axon not being stimulated
polarization
a difference of electrical charge on the two sides of the membrane
action potential
recorded from the axon
ARP = Absolute Refractory Period
no stimulus no matter how great it is capable of eliciting a response
RRP = relative refractory period
a greater than normal stimulus is capable of eliciting a response.
All- or -nothing- law
an axon fires completely or does not fire at all. (this law does not apply to dendrites and the cell body)
the synapse
place where information is transferred between neurons. ( gap between nerve cells)
Terminal bouton
a swelling at the end of the branch of the axon of the presynaptic cell
synaptic cleft
a gap between the terminal bouton and the postsynaptic cell= synapse
synaptic vesicles
the site of synthesis storage, and release of a neurotransmitter
neurotransmitter
the chemical that is caused by the action potential arriving at the terminal bouton, this chemical is then released from the synaptic vesicles into the synaptic cleft
receptor sites
the neurotransmitter diffuses across the cleft and becomes attached to ..... in the surface of the post synaptic cell
Excitatory Postsynaptic Potential (EPSP)
when the neurotransmitter attaches to a receptor site it causes a depolarization of the membrane surrounding the synapse on the postsynaptic cell by permitting ions to cross the membrane. this depolarization is called....
Inhibitory Postsynaptic Potential (IPSP)
at these synapses the neurotransmitters hyperpolarizes the postsynaptic membrane making it harder for the cell to produce action potentials
1. depolarization of membrane allows entry of CA++
2. CA++ causes the vesicles to fuse with plasma membrane
3. Neurotransmitters released (e.g. acetylcholine)
4. Neurotransmitter binds to receptor
NA+ gates open => depolarization EPSP
Summary of Synaptic transmission
autoreceptors
receptors on neurons through which neurons regulate their own activity (i.e thier excitability and release of their own neurotransmitters)
called this because they activated by the same types of neurotransmitters released by neurons
to enhance the release of dopamine from axon terminals
one of the actions of amphetamine
basal ganglia
involved in motor cordination (affected in parkisons disease)
limbic lobe
part of the anatomical substrate for emotions
Hippocampus
involved in memory (transfering short term to long term)
destroy - memory deficits
Amygdala
an excitatory structure
destroy = tameness docility or placidity
Septum
an inhibitory structure
destroy-> rage
recticular formation
overlaps the forebrain, midbrain, and hindbrain.
this part of the brain alerts and arouses the cortex
many drugs ( sleeping pills and stimulants) act on this part of the brain