Nervous Tissue the neuron

embryonic neural tube & neuro crest

neurons & glial cells (supporting cells)

• excitable
• can send an impulse (electrical signal)
• three major parts - cell body, dendrites, axon
• cells live for many years
• do not undergo mitosis
• highly dependant on oxygen due to high metabolic rate

receptive ends allowing signals to travel towards cell body

extend out of one side of cell body called axon hillock

resut when axons branch

multiple branches at the end of an axon

end in knobs

where the length of axon is surrounded by

myelin sheath

a gap between each schawnn cell

connecting allowing one neuron to communicate with the next

axon makes synapse with dendrite

axon connects with cell body of another neuron

synapse exists between two axons

presynaptic neuron - cell conducting impulse towards synapse

postsynaptic neuron - recieves impulse & sends it away from synapse

chemical substance allowing impulse to jump from neuron to neuron

membrane bound sacs containing neurotransmitter

gap seperating plasma membrane of two neurons

electrical signal sent down plasma membrane of neuron

RP: neuron not sending any type of impulse

AP: impulse travels down axons and as it leaves, axon returns to resting potential

GP: travels toward axon hillock & initiates impulse

• SP
• - excitatory synapse- changes potential so postsynaptic neuron can send impulse
• - inhibitory synapse - stops travel of an impulse

neurons that have receptors in PNS & send signals toward CNS

cells capturing stimulus & transfer signal onto dendrite of sensory neuron with the dendrite connecting to cell body sending axon into CNS (spinal cord)

multipolar neurons with cell bodies in CNS & connect in body to effector cells (muscles/glands)

muscle/glands

multipolar neurons in CNS linking sensory & motor neurons relaying messages to & from brain & process information

• sensory neuron - afferent
• interneuron - association
• motor neuron - efferent