Neurology
Body system that coordinates and controls all activities of the body; brain, spinal cord, and nerves
Nervous system
Main organ of the nervous system; controls the body
Brain
Largest part of the brain; controls the process of thinking and reasoning; receives and interprets information from sense organs
Cerebrum
Organ made of bundles of nerve fibers; transmits messages between the central nervous system and one or more specific regions of the body
Nerve
Nerve fiber that carries signals from the body to the central nervous system
Sensory nerve fiber
Focuses light that enters the eye by refracting it; changes shape to focus on objects at different distances
Lens
Division of the ear that consists of the cup-shaped structure on the side of the head and of the auditory canal
Outer ear
Nerve cell; cell that transmits messages within the body
Neuron
Quick, automatic action that the body does in response to something else
Reflex
Part of the brain that controls balance and coordination of voluntary muscles
Cerebellum
The way that the body responds to unfamiliar or difficult circumstances
Stress
Special cell or group of cells that detects a sensation and sends a message on a sensory nerve fiber
Sense receptor
Ring of muscles that surrounds the pupil and controls its size; colored part of the eye
Iris
Thin piece of tissue that separates the outer ear from the middle ear
Eardrum
Central part of a neuron containing the nucleus and organelles
Cell body
Cranial nerve that carries messages of sight to the cerebrum
Optic nerve
Bundle of nerve cells attached to the base of the brainstem; carries messages between the brain and the rest of the body
Division of the ear that is a cavity inside the skull; contains three tiny bones: the hammer, the anvil, and the stirrup
Middle ear
Nerve that branches from the spinal cord and travels to the muscles and organs
Spinal nerve
Round hole that lets light into the eye
Pupil
Division of the ear that contains the cochlea and semicircular canals
Inner ear
Short, branching part of a neuron that extends from the cell body
Dendrite
Injury of a torn eardrum
Ruptured eardrum
Controls involuntary functions of the body; "turns off" and "turns on" cerebrum for sleeping and waking
Brain stem
Nerve that carries messages of hearing from the cochlea to the brain
Auditory nerve
Nerve that branches directly from the brain
Cranial nerve
Transparent front portion of the eye; lets light into the eye
Cornea
Three inner-ear structures that detect movements of the head; send information that the brain uses to help keep balance
Semicircular canals
Long, straight part of a neuron that extends from the cell body
Axon
Layer of nerve cells in the back of the eye; contains rod cells and cone cells
Retina
Part of the brain that helps you coordinate emotions, alerts you of physical needs, and is important for forming memories; includes an emotional reward system
Limbic system
Part of the ear that detects sound waves and sends them as messages to the brain
Cochlea
Nerve fiber that controls some part of the body by delivering messages from the central nervous system; carries a single message to an individual cell or group of cells
Motor nerve fiber
White of the eye
Sclera
Tube of the outer ear through which sound waves travel
Auditory canal