The nervous system Flashcards
What is the CNS composed of?
brain and spinal cord
What is the PNS composed of?
nerves, sensory receptors, and ganglia
nerve cells
-basic functional unit of nervous system
-transmit messages via nerve impulses
neurons
supporting cells
-astrocytes
-digodendrocytes
-microglial cells
-ependymal cells
neuroglia
-most abundant
-control chemical environment around neuron
-capillary-neuron exchanges
- can supply nutrients to neurons and cells which establish blood-brain barrier
astrocytes
-defensive cells
-phagocytic-engulf pathogens and cellular debris
microglial cells
-line ventricles, production and regulation of cerebral spinal fluid (CSF)
-cilia circulate CSF
ependymal cells
-form myelin sheath on CNS axons
-needed for insulation
-action potential (AP) propagation
-schwann cells in PNS
oligodendrocytes
precursors to skeletal muscle cells
satellite cells
-myelin forming cells of PNS
-insulation and AP propagation
schwann cells
receptive region
cell body (soma)
cytoskeleton
neurofibrils
clusters of rough er
chromatophilic substance
receptive regions for neurotransmitters
dendrites
-conducting regions
-impulse generation
axons
site of neurotransmitter release
axon terminal
where signals propagate before action potential is initiated
axon hillock
formed between neuron and its target
synapse
small gap between axon terminals and target where neurotransmitters are released
synaptic cleft
-fatty, insulating material
-surrounds axons
myelin
gaps in between myelin sheaths
nodes of ranvier
has 1 small process
unipolar
- has 2 processes attached to cell body
- eye, ear, olfactory nerves
bipolar
has multiple dendrites, single axon
multipolar
sensory neurons
-from body to CNS
AWAY FROM BODY
afferent
motor neurons
-from CNS to body
EXITING FROM CNS
efferent
-help to connect neurons
-help to transmit signals
interneurons
for CNS bundles of axons are called
tracts
for PNS bundles of axons are called
nerves
delicate connective tissue surrounding axon addition to myelin sheath
endoneurium
bundles axons together to form fascicles
perineurium
white fibrous tissue, binds fascicles together
epineurium
