1. Nerve Notes

2. NEURON Nerve tissue are made of neuron (nerve cell) and neuroglia
Neuron are made of:
Cell body – contains nucleus and other organelles
Dendrites – receiving portions, short, tapered and highly branched

4. Axon – conducts nerve impulses to another neuron or to an effector organ (muscle or gland)
Axon arises from the axon hillock
Axons start as a single fiber, but may give off branches called axon collaterals

6. Axon and collaterals end in axon terminals which end in synaptic end bulbs
end bulbs contain synaptic vesicles that contain neurotransmitters (chemical messengers)

8. MYELIN increases the speed at which the impulse travels
Most axons are surrounded by a myelin sheath
Myelin acts as an insulator
increases the speed at which the impulse travels
Gaps between myelin sheath are called the nodes of Ranvier

11. CLASSIFICATION OF NEURON
Multipolar – several dendrites and one axon – neurons of CNS are mostly this type
Bipolar – one main dendrite and one axon – usually found in special sense organs

12. Unipolar - just one process, and are always sensory neurons
Unipolar - just one process, and are always sensory neurons. Axon terminals are in CNS and cell bodies in ganglia outside CNS

13. FUNCTIONAL CLASSIFICATION
Sensory or afferent neurons – transmit sensory impulses (toward CNS), have specialized receptor ends at tips of dendrites or the dendrites are in contact with specialized receptor cells in skin or sense organs
Most are unipolar, some are bipolar

14. Motor or efferent neurons – transmit motor nerve impulses from CNS to effectors
Interneurons – multipolar neurons in CNS.that form links between other neurons