Neuron Cell that carries messages throughout the nervous system
Cell Body Largest part of a typical neuron, contains the nucleus and much of the cytoplasm
Dendrite extension of the cell body of a neuron that carries impulses from the environment or from other neurons toward the cell body
Axon Long fiber that carries impulses away from the cell body of a neuron
Myelin Sheath Insulating membrane surrounding the axon on some neurons
Resting Potential Difference in electrical charge across the cell membrane of a resting neuron
Action Potential Reversal of charges across the cell membrane of a neuron
Threshold minimum level of a stimulus that is required to activate a neuron
Synapse location at which a neuron can transfer an impulse to another cell
Neurotransmitter Chemical used by a neuron to transmit an impulse across a synapse to another cell
Central Nervous System The brain and spinal cord
Meninges Three layers of connective tissuse in which the brain and spinal column are wrapped
Cerebrospinal Fluid fluid in the space between the meninges that acts as a shock absorber that protects the central nervous system
Cerebrum Area of the brain responsible for all voluntary activities of the body
Cerebellum Region of the brain that coordinates body movements
Brain Stem Connects brain to spinal cord; contains medulla oblongata
Thalamus brain structure that receives messages from the sense organs and relays the information to the proper region of the cerebrum for further processing
Hypothalamus Brain structure that acts as a control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature
Reflex quick automatic response to a stimulus
Sensory Receptor Neuron that reacts directly to light, sound or other stimuli by sending impulses to other neurons and eventually to the central nervous system