Nerve Cells & Neurotransmission

The Brain:• Made up of millions

of nerve cells called neurons

Neuron contains 3 Parts:

Dendrites:• Receive message

Axon• Transmits

messages from the cell body to other dendrites or body tissues (muscles)

Cell Body • Directs all activities

of the neuron

Neurotransmission• Transfer of a

message from the axon of 1 nerve cell to the dendrites of another.

• Does not have direct contact

Neurotransmission

Communication between nerve cells:

• Occurs through the release of chemical substances (neurotransmitters) into the space between the axon & dendrite (synapse)

When Neurons communicate:

• A message (electrical impulse) travels down the axon to the synapse

• This triggers the release of neurotransmitters into the synapse

Neurotransmitters (chemical messengers)

• Diffuse across the synapse • Bind to receptors • This stimulates (starts) or inhibits

(stops) an electrical impulse in the receiving neuron’s dendrites.

Neurotransmitters

• Very specific• Like a lock & key• Reusable

Myelin:• Fatty substance• Covers axons• Increases rate of

conduction (how fast the message travels)

• 120 meters/second verses 2 meters/second