a change in an organism's surroundings that causes the organism to react
an action or change in behavior that occurs as a result of a stimulus
cell that carries messages throughout the nervous system
the message carried by a neuron
a threadlike extension of a neuron that carries nerve impulses toward the cell body
a threadlike extension of a neuron that carries nerve impulses away from the cell body
a bundle of nerve fibers
a neuron that picks up stimuli from the internal or external environment and converts each stimulus into a nerve impulse
a neuron that carries nerve impulses from one neuron to another
a neuron that sends an impulse to a muscle or gland, causing the muscle or gland to react
tiny space between the tip of an axon and the next structure
central nervous system
consists of the brain and the spinal cord
peripheral nervous system
The section of the nervous system lying outside the brain and spinal cord, connects central to all parts of the body
the part of the central nervous system in the skull controls most functions of the body
the thick column of nerve tissue that links the brain to most of the nerves in the peripheral nervous system
the part of the brain that interprets input from the senses, controls the movement of skeletal muscles, and carries out complex mental processes
the part of the brain that coordinates the actions of the muscles and helps maintain balance
the part of the brain that controls many body functions that occur automatically
somatic nervous system
the group of nerves that controls voluntary actions
autonomatic nervous system
group of nerves that controls involuntary actions
an automatic response that occurs very rapidly and without concious control
a bruise like injury of the brain that occurs when the cerebrum bumps against the skull
the clear tissue that covers the front of the eye
the opening in the eye in which ligt enters
the circular structure that surrounds the pupil and regulates amount of light entering the eye.
the flexible structure that focuses light that has entered the eye.
the layer of receptor cells at the back of the eye on which the image is focused; nerve implusesare sent from the retina to the brain
the codition in which nearby objects are seen clearly but distant objects are blury.
the condition in which distant items are clear but near objects are blury
the membrane that seperates the outer ear from the middle ear and that vibrates when sound waves strike it.
a snail-shaped tube in the inner ear lined with sound receptors; nerve impulses are sent from the cochlea to the brain
structures in the inner ear that are responsible for the sense of balance.
any cheamical that causes change in a persons body or behaivior
the delibrate misuse of drugs for purposes other than appropriate medical ones
a state in which a drug user ,after repeatedly taking a drug ,needs larger and larger doses of the drug to produce the same affect
a period of adjustment that occurs when a drug-dependent person stops taking the drug
a drug that slows down activity of the central nervous system
a drug that speeds up body processes
synthetic chemicals that are similar to hormons produced in the body and that may increase muscle size and cause mood swings
a disease in which a person is bothphisically addicted to and emotionaly dependent on alcohol.