1. Nervous Tissue

2. Neuron (motor)

3.  Nerves – bundles of neurons held together by connective tissue (found in PNS)  Neurons – specialized nerve cells that make up both the CNS and PNS - many different types  Dendrites – extensions of cell body that conduct nerve impulses toward cell body Parts of a Neuron

4.  Axons – carries impulse away from cell body to next nerve cell, muscle or gland  Myelin – lipid sheath that covers some axons, provides a thick pad of insulation  Schwann cells – places on axon covered with myelin sheath  Nodes of Ranvier – gaps between Schwann cells, no myelin at that spot

5. Neural Circuits 1. receptor cells receives sufficient stimuli 2. sensory (afferent) neurons carry info to CNS 3. Interneurons in CNS interpret info and stimulate motor neurons 4. motor (efferent) neurons carry info to effectors (muscles, glands, organs) 5. response to stimuli is produced

6. Reflex Arc  involuntary & unconscious  stimuli to spinal cord via sensory  interneurons interpret respond via motor (send info to brain at same time)  effectors activated  prevents damage in cases of emergency  YouTube - The Nervous System ( Animation ) YouTube - The Nervous System ( Animation )