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44 terms

neurons

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has organelles that provide structural support and energy, and manufacture needed materials (neurotransmitters)
cell body
olfactory
neurons do regenarate--research is focusing on triggers to activate stem cells
neurons
cannot divide--can't be replaced if damaged or killed
extensions of the cell body
dendrites and axons
usually only one
axon
axon
carries action potential away from the cell body
branches many times (hundreds or thousands) and end at the synaptic end bulb
axon
axon hillock
enlarged area of the cell body
extends from the axon hillock
axon
site where a neuron communicates with another cell
synapse
presynaptic cell and postsynaptic cell
two cells of the synapse
presynaptic cell
synaptic terminal; cell that sends a message--usually a neuron
postsynaptic cell
receives the message--almost any cell in the body
involves neurotransmitters released by the presynaptic cell that affect the postsynaptic cell
communication
stored in vesicles at the end of the axon and are released into the synaptic cleft
neurotransmitters (like ACH)
movement of materials between the cell body and the synaptic end bulbs
axoplasmic transport
flow from the cell body
anterograde
anterograde
neurotransmitters and other materials (like calcium) needed at the end of the axon
flow toward the cell body
retrograde
retrograde
waste products and debris
classified by structure and function
neuron
anaxonic, bipolar, unipolar, multipolar, sensory (afferent) neurons, motor (efferent), interneurons (association neurons)
classifications of neurons
small, all processes look alike
anaxonic
two processes: one dendrite and one axon with the cell body inbetween
bipolar
found in the brain and special sense organs (eyes, ears), but their function isn't clear
anaxonic
found in special sense organs
bipolar
unipolar
dendrite and axon are continuous and cell body is off to the side
sensory neurons in the peripheral nervous system
unipolar
multipolar
most common type of neuron in the central nervous system
has two or more dendrites and a single axon
multipolar
motor nerves that control skeletal muscles
multipolar
somatic, visceral, proprioceptors
sensory (afferent) neurons
sensory (afferent) neurons
deliver sensory information from the pns to the cns (about 10 million)
somatic
monitor the outside world (exteroceptors)
visceral
monitor the internal environment (interoceptors)
proprioceptors
monitor the body's position
carry instructions from the cns to the pns (about 500,000)
motor (efferent)
somatic and visceral
motor neurons
somatic motor neurons
innervate skeletal muscles
cell body lies in the cns and the axon extends to the target muscle
somatic motor neurons
innervate cardiac and smooth muscle as well as glands and organs
visceral motor neurons
provide communication between sensory and motor neurons ( 20 billion)
interneurons
interneurons
association neurons
most common type of neuron; found in the brain and spinal cord; involved in learning and memory
interneurons (association neurons)