1. KEY CONCEPT The nervous system is composed of highly specialized cells.

2. Neurons are highly specialized cells.
A neuron has three parts.
cell body has nucleus and organelles 1
Cell body

3. Neurons are highly specialized cells.
A neuron has three parts.
cell body has nucleus and organelles
dendrites receive impulses 2
dendrites

4. Neurons are highly specialized cells.
A neuron has three parts.
cell body has nucleus and organelles
dendrites receive impulses
axon carries impulses 3
axon

5. Neurons have other structures to transmit signals.
Schwann cell

6. Neurons have other structures to transmit signals.
Schwann cell
synapse
synapse

7. Neurons have other structures to transmit signals.
Schwann cell
synapse
terminal
axon terminal

8. Neurons receive and transmit signals.
Resting potential means no signal is being transmitted.
more Na+ outside of cell
more K+ inside of cell

9. An action potential is a moving electrical impulse.
It is generated by a stimulus.
Na+ enters, and cell becomes positively charged.
K+ leaves, and area of positive charge moves.
area of detail

10. A chemical signal passes between neurons.
Impulse reaches terminal.
impulse

11. A chemical signal passes between neurons.
Impulse reaches terminal.
impulse

12. A chemical signal passes between neurons.
Impulse reaches terminal.
Neurotransmitters released into synapse.
synapse
impulse
neurotransmitter
vesicles
receptor

13. A chemical signal passes between neurons.
Impulse reaches terminal.
Neurotransmitters released into synapse.
Neurotransmitters stimulate next cell.
synapse
impulse
neurotransmitter
vesicles
receptor

14. There are three kinds of neurons.
Sensory neurons are part of the peripheral nervous system (PNS). These neurons detect stimuli and bring signals to the central nervous system (CNS).
Interneurons are found in the CNS. They transmit and process signals in the brain and spinal cord.
Motor neurons are those in the PNS that produce responses by taking messages from the CNS and bringing them to a muscle or organ.