| A | B |
|---|
| glial cell | Comprises 90% of the brain; supports and insulates nerve cellls. |
| neuron | Building block of the nervous system; sends and receives messages. |
| synapse | Gap between nerve cells; messages travel chemically here. |
| glucose | Provides fuel for the brain. |
| dendrite | Branch-like structure of a nerve cell that receives messages. |
| axon | Long arm of the nerve cell; sends messages to the next cell. |
| neurotransmitter | Chemical messenger in the nervous system. |
| myelin sheath | Protective coating around arms of nerve cells; helps messages to travel faster and reduces electrical interference. |
| somatic nervous system | Regulates voluntary sensory receptors and muscles. |
| autonomic nervous system | Regulates physiological responses that are automatic and involuntary. |
| peripheral nervous system | All nerves extending from the spinal cord to the rest of the body. |
| central nervous system | Brain & spinal cord. |
| sympathetic nervous system | Speeds up body functions (heartrate, blood supply, adrenal glands, sweaty palms); fight or flight reactions. |
| parasympathetic nervous system | Slows down body functions; relaxes; stimulates digestion. |
| efferent nerve | Carries information from the spinal cord to muscles and organs in the body. |
| afferent nerve | Carries information from the body senses to the spinal cord. |
| excitatory transmitter | Opens chemical locks and send on a message. |
| inhibitory transmitter | Blocks checmical locks and prevent a message from being sent on. |
| all-or-none law | If an action potential starts through an axon; it will continue at the same speed all the way to the end. |
| end bulbs | Structures that store neurotransmitters and release them into the synapse. |
| soma | Cell body. |
| hormone | Chemical messenger in the endocrine system. |
