Term | Definition |
Neuron | basic functioning unit of the nervous system, made up of a body cell, dendrites and axons |
Impulse | any message carried by a neuron |
Dendrites | a neuron structure that receives impulses (messages) from other neurons and send them to the cell body |
Axon | a neuron structure that carries impulses (messages) away from the cell body |
Sensory Neurons | receive information and send impulses to the brain or spinal cord |
Interneurons | relay sensory neuron impulses to motor neurons |
Motor Neurons | conduct impulses from the brain or spinal cord to muscles or glands throughout the body |
Synapse | a small space across which an impulse moves from an axon to dendrites or cell body of another neuron |
Central Nervous System | division of the nervous system, made up of the brain and spinal cord |
Cerebellum | part of the brain that controls voluntary muscle movements, maintains muscle tone and helps maintain balance |
Cerebrum | largest part of the brain where memory is stored, movements are controlled and impulses from the senses are interpreted |
Brain Stem | connects the brain to the spinal cord |
Spinal Cord | an extension of the brain stem made up of neurons that carry impulses from all parts of the body to the brain and from the brain to all parts of your body |
Peripheral Nervous System | the brain and spinal cord are connected to the rest of your body by the PNS |
Somatic Nervous System | a division of the PNS which controls voluntary actions |
Autonomic Nervous System | a division of the PNS which controls involuntary actions such as heart rate, breathing and digestion |
Reflex | an involuntary, automatic response to a stimulus controlled by the spinal cord |
Reflex Arc | a simple nerve pathway |
Stimulant | a drug that speeds up the activities of the Central Nervous System |
Depressant | a drug that slows the activities of the Central Nervous System |
Paralysis | the loss of muscle movement |
Cornea | the transparent section at the front of the eye |
Retina | -a tissue at the back of the eye that is sensitive to light energy
-two types of cells, rods(dim light) and cones (bright lights and color) |
Lens | directs the light onto the cornea of the eye |
Concave Lens | -a lens that is thicker at the edges than in the middle
-causes parallel light to spread out |
Convex Lens | -a lens that is thicker in the middle and thinner on the edges |
Nearsightedness | a nearsighted person can not see distant objects because the image is focused in the front of the retina |
Farsightedness | a farsighted person cannot see close because the image is focused behind the retina |