Unit 2 Nervous Flashcards
neural tube gives rise to
CNS
which germ layer gives rise to the nervous system?
ectoderm
NS function
master controlling/communicating system of the body
cells communicate via electrical and chemical signals
NS cycle
sensory input
integration
motor output
sensory input
information gathered by sensory receptors about internal and external changes
integration
processing and interpretation of sensory input
motor output
activation of effector organs (muscles and glands) produces a response
NS characteristics
tissue almost entirely cellular, little ECM
cells chemically linked to form circuits
includes excitable cells; able to conduct stimulus
NS cell types
neuroglia (glial cells)
neurons (nerve cells)
neuroglia
small cells that surround and wrap delicate neurons
neurons
excitable cells that transmit electric signals
neurons
structural cells
large, highly specialized that conduct impulses
have cell body and process(es)
neuron characteristics
post mitotic
irritable
high metabolic rate
neuron components
prominent nucleolus
abundant RER and polyribosomes
axon
dendrite
axon
single process constant diameter conduct action potential away from body axon hillock axolemma axoplasm
dendrites
vary in number
tapers away
conducts graded potentials toward cell body
anatomical classification of neurons
bipolar
pseudounipolar
unipolar
multipolar
bipolar neuron
one dendrite
one axon
mostly sensory
e.g. cochlear, vestibular ganglia, olfactory mucosa, retina of eye
pseudounipolar
one branched process
found in dorsal root ganglia
contain central and peripheral process
synapse
site of contact between neurons and other cells
maintains unidirectional transmission of nerve impulse
synapse types
electrical
chemical