Types of Neurons and Types of Neurons and Nerve ImpulsesNerve Impulses

Parts of a NeuronParts of a Neuron

Cell bodyCell body

Axon – nerve fiber running Axon – nerve fiber running from cell body to synapsefrom cell body to synapse

Synapse – terminating end of Synapse – terminating end of neuronneuron

Dendrite – branched receptors Dendrite – branched receptors on cell bodyon cell body

Myelin sheath – fat deposits Myelin sheath – fat deposits that insulate axonthat insulate axon

Nodes of Ranvier- gaps in m.s.Nodes of Ranvier- gaps in m.s.

Classifying NeuronsClassifying Neurons

Can be classified by functionCan be classified by function

Sensory neurons-Sensory neurons- Begin afferent pathwayBegin afferent pathway Receptors or naked nerve endings (pain)Receptors or naked nerve endings (pain)

Motor NeuronsMotor Neurons Efferent pathwayEfferent pathway

InterneuronsInterneurons Connect motor and sensory neuronsConnect motor and sensory neurons

Types of NeuronsTypes of Neurons

Multipolar – multiple Multipolar – multiple fibers extending from fibers extending from the cell body the cell body Ie. Motor neuronsIe. Motor neurons

Bipolar – two fibersBipolar – two fibers Ie. Interneurons Ie. Interneurons

Unipolar – only one Unipolar – only one processprocess Ie. Sensory neuronsIe. Sensory neurons

In PNSIn PNS

Action potential travels faster because of Action potential travels faster because of Schwann cellsSchwann cells

Can’t move through myelin, so skips over Can’t move through myelin, so skips over them, causing impulse to travel fasterthem, causing impulse to travel faster

Blocking Nerve ImpulsesBlocking Nerve ImpulsesSome things can slow down or stop nerve Some things can slow down or stop nerve transmissiontransmission

Alcohol, Drugs, Anesthetics, can all slow down Alcohol, Drugs, Anesthetics, can all slow down nerve transmission.nerve transmission.