nervous system Flashcards
neurons
50% of cells in nervous system
- excitable, neurotransmission
general function of nervous system
- detect + analyze sensory input
- coordination
- learning
- interacting with environment
CNS
brain + spinal cord
PNS
all nerves, motor/sensory info
pre-central gyrus
1* motor cortex
- limbs medial, face lateral
post-central gyrus
1* sensory cortex
- limbs medial, face lateral
association cortices
make up most of cortical mantle
- integrate between brain regions -> cognition
grey matter
cell bodies
white matter
myealinated nerve fibers
dorsal horn
sensory
ventral horn
motor
dorsal root ganglion
sensory neuronal cell bodies (PNS to CNS)
dendrites
receptive, conduct impulse to cell body
- mitochondria, SER, MTs, neurofilaments
- NO golgi
soma
nucleus, golgi, RER
Nissl body: RER
- Nissl stain reacts with acids
axon
conductive, sends impulses away from cell body
- mitochondria, MTs, and SER
- NO RER
microtubules
in axons and dendrites
- anterograde: load and transport vesicles to axon terminals
- retrograde: reuptake and recycle NT material to cell body
transport of mitochondria, proteins, structural components
synaptic transmission
- vesicle loading near cell body
- vesicle transport w MT
- depolarization
- fusion/exocytosis
- NT binding
- Depolarization
glia
non-conducting, but enhance transmission
- structural support
- provide nutrients for growth and maintenance
- immune function
- biochemical (regulate AP velocity)
heavy myelination
less leaky + energy consuming
- impulse propagation more efficient (nodes) and faster
- somatic motor neurons
- acute pain sensory neurons
moderate or un-myelinated
leak Na+ ions
- channels must open along entire length (inefficient)
- slow
- autonomic motor neurons
- chronic pain sensory neurons
multiple sclerosis
loss of myelin (autoimmune)
myelinating schwann cells
PNS, produce myelin sheath
unmyelinating schwann cells
PNS, axon maintenance and repair
- can have multiple nerve axons nearby
oligodendrocyte
CNS, produce myelin
- can contact >60 axons
microglia
shield neurons from injury
- extend and retract processes to sites of injury
- stimulated by chemoattractants
protoplasmic and fibrous astrocytes
scavenge ions, supply nutrients to neurons
- contact blood vessels
- secrete factors with either barrier-promoting or barrier-disrupting properties (BBB)
brain homeostasis
capillary neural endothelium
ependymal cells
capillary neural endothelium
tight lining of blood vessels
- BBB
- continuous tight junctions
- restrict large molecules
can pass: lipid-soluble, astrocyte processes, membrane-bound pumps for water-soluble molec (CSF)
ependymal cells
lining of brain
- synth + secrete CSF into ventricular system
- part of BBB
ventricular system
contains CSF
- 4 cavities
cerebrospinal fluid
liquid cushion, contains nutrients and NTs
- within 3rd and 4th ventricle, the choroid plexus prod CSF
- tight junctions between epithelial cells control fluid release
choroid plexus
produces CSF
- ependymal cells of 3rd + 4th ventricles and capillaries (tela choroidea)
- separates blood from CSF (BBB)
CSF circulation
- ions, water, organic molec filter out of CP capillaries into ISF, then into CP epithelium (active transport)
- CSF secreted into ventricles
meninges
dura mater (outside), arachnoid mater, subarachnoid space (CSF), pia mater
