Parts of Neurons

Dendrites

Nerve fibers that bring impulses to cell body from previous neuron, may be 100s/neuron

Cell body (soma)

Main part of neuron; contains all organelles; ^^LACKS CENTRIOLES^^- __no mitosis__

Axon hillock

Cone-like region of cell body where axon begins

Neurofibrils

Fibers that run the length of axon and give structural support

Axon

Nerve fiber extending from cell body; carries impulse away from cell body and eventually to dendrites of next neuron” only ONE axon per neuron

Collateral branch

Initial branches off of main axon

Schwann cells

Segments of axon covered in myelin; found on axons outside CNS; covers small portion of ONE axon

Myelin/Myelin sheath

Lipid, fatty layer covering and insulating axon; allows impulse to travel quickly

(w/myelin = 100m/sec, w/o myelin=1m/sec)

In CNS, oligodendrocytes from myelin which can protect many fibers at one time

Nodes of Ranvier

Very small, unmyelinated segments along axon between each schwann cell; regulate speed of impulses

Axon terminals

Fiber branches at ends of axon

Synaptic knobs

Enlarged ends of axon terminals; ^^Neurotransmitters^^

Synapse/Synaptic cleft

Very tiny space between synaptic knobs and the dendrites of the next neuron