1. Nervous System & Senses

2. Neuron A neuron is the basic unit of the Nervous System. Carry messages in the form of electrical impulses.

3. Neuron Structure Three Basic Parts: A.Axon – carry impulse away from cell body B.Dendrites – carry impulses toward cell body C.Cell Body – largest part, contains the nucleus

4. Three Main Types 1.Sensory : body to brain 2.Motor : brain to body 3.Interneuron : found in brain & spinal cord; process incoming impulses and pass them to motor neurons

5. Synapse Synapse: The space between the axon terminal of one neuron and the dendrites of the next neuron. Drugs & alcohol Molecules get In the Synapse and Prevent messages From relaying properly Messages jump across the synapse like an electrical current

6. Central Nervous System Two Parts: Brain Spinal Cord

7. Peripheral Nervous System All nerves outside of brain and spinal cord Sensory – receives internal and external stimuli Motor – controls muscles and glands

8. Peripheral Nervous System 1.Somatic NS – controls all voluntary activity 2.Autonomic NS – involuntary activity Sympathetic – controls body during times of stress - Works with endocrine system for fight or flight –Ex - speeds up heart rate Parasympathetic – controls body normally, returns body to normal state after stress –Ex – slows heart rate

9. Sight, Sound, Taste, Touch, Smell There are 5 general categories of sense receptors. –Pain receptors –Thermoreceptors - temperature –Mechanoreceptors – touch, sound –Chemoreceptors - chemicals –Photoreceptors - light