| A | B |
|---|
| dendrite | the part of the neuron that receives a nerve impulse |
| axon | the part of the neuron that carries an impulse to another nerve, a muscle or a gland |
| myelin sheath | a lipid covering on the axon |
| neurotransmitter | a chemical that carries a nerve impulse across a synapse |
| synapse | the space between the axon of one nerve and the dendrites of another nerve |
| reflex arc | a reaction to a stimulus without direction from the brain |
| sodium | the type of ion that rushes into a neuron during a nerve impulse |
| Node of Ranvier | a space in the myelin sheath |
| central nervous system | the nervous system that consists of the brain and the spinal cord |
| somatic nervous system | the part of the periferal nervous system that carries messages to and from the extremities |
| autonomic nervous system | the part of the periferal nervous system that carries messages to and from the internal organs |
| sympathetic nervous system | the part of the autonomic nervous system that stimulates the body to react to danger |
| parasympathetic nervous system | the part of the autonomic nervous system that stimulates the body to return to normal after a danger has passed |
| periferal nervous system | the part of the nervous system that includes the sympathetic and parasympathetic nervous systems |
| cerebrum | the part of the brain that is involved in thinking, memory, language, and consciousness |
| cerebellum | the part of the brain that is involved in muscle coordination |
| medulla oblongata | the part of the brain that controls heartbeat, respiration, and other body functions |
| corpus callosum | the axons that connect the left and right hemispheres of the brain |
| brain stem | portion of the brain consisting of the medulla oblongata, pons, and midbrain |
| limbic system | part of the brain that governs learning, memory and emotions |
| neuroglia | nonconducting nerve cells |
| Schwann cell | forms the myelin sheath in periferal nerves |
