Cell that carries messages throughout the nervous system.
Extension of the cell body of a neuron that carries impulses from the environment or from other neurons toward the cell body.
Insulting membrane surrounding the axon in some neurons.
Minimum level of a stimulus required to activate a neuron.
Largest part of a typical neuron; conatins the nucleus and much of the cytoplasm.
Long fiber that carries impulses away from the cell body of a neuron.
Muscle Nervous Connective Epithelial tissue
Four basic types of tissue...
Process by which organisms maintain a relatively stable environment.
Process in which the product or result stops or limits the process.
Three layers of connective tissue in which the brain and spinal cord are wrapped.
Fluid in the space between the meninges that acts as a shock absorber that protects the central nervous system.
Area of the brain responsible for all voluntary activities of the body.
Region of the brain that coordinates body movements.
Quick automatic response to a stimulus.
Sensory receptor, sensory neuron, motor neuron, and effector that are involved in a quick response to a stimulus.
Neuron that reacts to a specific stimulus, such as light or sound, by sending impulses to other neurons and eventually to the central nervous system.
Small opening in the middle of the iris through which light enters the eye.
Transparent object behind the iris that changes shape to help adjust the eye's focus to see near or distant objects.
Innermost layer of the eye; contains photoreceptors.
Photoreceptor in eye that is sensitive to light but not to colors.
A photoreceptor that responds to the light of different colors, producing color vision.
Any substance, other than food, that causes a change in the structure or function of the body.
Drug that decreases the rate of functions regulated by the brain.
Fetal Alcohol Syndrome
Group of birth defects caused by the effects of alcohol on a fetus.
Intentional misuse of any drug for nonmedical purposes.
Uncontrollable dependence on a drug.