MCM Final - Nerve Tissue Flashcards
PNS
cranial nerves, spinal nerves, peripheral nerves
CNS
brain and spinal cord
ganglia
collection of nerve bodies (outside the CNS)
nucleus
collection of nerve bodies (outside the CNS)
two cell types in nerve tissue
neurons and glial cells
perikaryon
cell body of neuron
has prominent nucleolus (RNA production)
also has nissl body and axon hillock
nissl bodies
rER where ribosomes are located
axon hillock
area of junction between axon and cell body
axon
conveys information away from the cell body
have cytoskeleton, mitochondria, and vesicles
anterograde transport
carry material from the cell body to the periphery
utilizes kinesin
retrograde transport
carries material from periphery to the cell body
dynein
dendritic cytoplasm
has no golgi!
purkinje neuron
in the cerebellum
has a gigantic dendritic tree
types of synapses
axodendritic, axosomatic, and axoaxonic
interneurons
communicate info between sensory and motor neurons
multipolar
one axon and two or more dendrites
bipolar
one axon and one dendrite
pseudounipolar
one process extends from cell body and divides into two long axons
astrocytes
CNS neuroglia
provide physical and metabolic support
maintain tight junctions
associated with nodes of ranvier
regulate K+ concentration
oligodendrocytes
produce CNS myelin sheath
one oligodendrocyte can myelinate several axons
microglia
phagocytic cells in the CNS
ependymal cells
columnar cells that form single cell layer to line fluid filled cavities of the CNS
has apical surface, basal surface, lateral surface and choroid plexus
choiroid plexis
ependymal cells that produces CSF in the CNS
schwann cells
produce the myelin sheath in the PNS
only one schwann cell per axon
satellite cells
in the PNS and insulate and provide environmental support to neurons
enteric neuroglia
in the ganglia of PNS
analagous to astrocytes
presynaptic axon terminal
voltage gaged Ca2+ channel
open in response to depolarization
influx of calcium - drives vesicle docking and fusion
neurotransmitter released
postsynaptic excitatory receptors
open Na+ channels
-depolarization > activate action potential
postsynaptic inhibitory receptors
gated Cl- channels
-hyperpolarization > prevent action potential
Action Potential Mechanism
1 begins in axon hillock - voltage gated Na+ channels cause influx
2 Na+ channels close and K+ channels open - leads to efflux of potassium (returns membrane potential)
3 resting potential returns
saltatory conduction
sped up down axon bc of myelination
voltage changes at nodes of ranvier only
grey matter
nerve cell bodies, axons, dendrites, glial cells
no myelin
site of synapse
white matter
nerve axons, associated glial cells, and blood vessels
has myelin
meninges
connective tissue in the nervous system
dura mater
outermost layer close to skull
very tough tissue
arachnoid mater
beneath the dura
-subarachnoid space is location of CSF
Pia mater
delicate layer on surface of CNS
-continuous with connective tissue
blood-brain barrier
exists in the vascular carrying substances to the CNS
endothelial cells, basal lamina, and astrocyte foot processes
endoneurium
loose connective tissue covering individuals nerve fibers
perineurium
connective tissue covering nerve fascicles
maintains the perineurium
fascicle
bundle of nerve fibers
epineurium
dense irregular connective tissue covering the peripheral nerve
