1. Neuron Structure and Function

2. Nervous System  Nervous system is composed of specialized cells called neurons.  Neurons have long “arms” called axons and dendrites.  Axons carry impulses away from cell body.  Dendrites carry impulses to the cell body  Connections between axons and dendrites forms our intelligence.

3. Central Nervous system contains the brain & spinal cord. Cell bodies, axons, & dendrites in the human brain.

4. Peripheral Nervous system (PNS)  contains all nerves leading to and from the Central Nervous System  Sensory receptors: Nerves that carry impulses towards CNS  Detect light, pressure and heat. Pair share: Why do you think it is called the “peripheral” nervous system?

5. Motor neurons  Nerves that carry impulses from the CNS to muscles or glands.

6. Neuron Structure  Impulses are referred to as action potentials.  Dendrites receive action potentials from other neurons.  Axons carry action potentials to other neurons.  Dendrites take action potential to cell body, axons away from cell body. Cell bodies of neurons Axons Pair share: How many directions can a signal travel in an nerve cell?

7. myelin sheath  Serves to insulate axons & dendrites and therefore speed up the action potential.  The myelin sheath is made up of Schwann cells.

8. Nodes of Ranvier  The gaps between Schwann cells are called the Nodes of Ranvier.  The action potential jumps from Node of Ranvier to Node of Ranvier.

9. White board review 1. What are the 2 components of the central nervous system? 2. What 2 types of nerves make up the PNS? 3. What do Axons do?