Histo L1 Flashcards
Ganglia
Neuron cell bodies NOT in CNS
Plexuses arise from
Ventral rami
Characteristics of Neurons
Exterme longevity
Amitotic
High metabolic rate
Neuron cell body Name Function myelation Characteristic action potentials how many
Perikaryon Biosynthetic center of neuron Contain nissl bodies Always unmyelinated No action potentials One body per neuron
Dendrites Function myelination action potentials how many
Main receptive or input regions of neuron
Always unmyelinated
No action potentials
one or more dendrites per neuron
Axon Main function action potentials Myelination how many
conducting region of neuron
can generated action potentials
can be myelinated
One axon per neuron
Three neurons based on structure
multipolar (interneuron or motor neuron)
Bipolar (usually no action potential)
Unipolar
Three neurons based on function
sensory/afferent
motor/efferent
interneurons/associated neurons (between motor and sensory)
Bipolar neurons
abundance
location
rare
some special sensory like olfactory and eye
Mulitpolar
abundance
location
Type of functional neuron
Most abundant
Major neuron in CNS
will be interneuron or motor neuron
Unipolar
Location
PNS
common in dorsal root ganglia and sensory ganglia of cranial nerves
Most common synapses
Axodendritic: axon terminal and dendrive
Axosomatic: axon terminal and cell body
Steps of chemical synapse
Nerve impulse at presynaptic axon
Depolarize and open voltage gated Ca channels
Ca causes release of neurotransmitters
Neuros go across cleft, bind to postsynaptic
Opening of ligand gated channel
Ions flow in
Membrane potential
Three ways neurotransmitter can be removed from postynaptic receptor
Degradation by enzymes
Reuptake by astrocytes or presynaptic terminal
Diffusion away from synapse
Neuroglia types
Astrocyte Microglial cell Ependymal cells Oligodendrocyte Sensory neuron w/ schwann cells and satelliate cells
Oligodendroctye
Produce
Found in
Produce Myelin sheath
Found in white matter
Astrocytes Charateristic Size functions White vs grey
Perivascular feet Largest of neuroglia In white and grey but likes grey better Communication, controls ionic concentration around neurons Role in maintaining BBB
Neurolemmocyte
Schwann cell
White matter
Composed of _____ axons and some
White due to
Composed of myelinated axons and some neuroglia
White due to myelin
Gray matter
COmposed of (5)
Gray due to
composed of Neuronal cell bodies dendrites unmyelinated axons axon terminals neuroglia Gray due to Nissl bodies and lack of myelin
Ganglion
cluster of neuronal cell bodies in PNS
Nucleus
cluster of neuronal cell bodies in CNS
Nerve
Bundle of Neuronal Axons in PNS
Tract
Bundle of Neuronal Axons in CNS
A nerve contains (5)
Neuron processes (axons) Schwann cells Connective tissue Blood vessels Lymphatic tissue
Connective tissue associated with nerves (3)
Endoneurium
Perineurium
Epineurium
Fascicle contains
perineurium
Endoneurium
myelin sheath
axon
Pairs of crainial nerves
12
Pairs of spinal nerves
31
Function of myelin sheath
protect and electrically insulate axons from other axons
Increase speed of nerve impulse transmission
Rate of impulse propagation depends on
axon diameter
Myelination
Continuous vs saltatory conduction
Continuous: unmyelinated axons
Saltatory: myelinated axons
