 | Term | Definition |
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neuron |
a nerve cell; the basic building block of the nervous system. |
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brain |
specialized group of nerve cells that controls & coordinates activities of the nervous system |
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cns |
the portion of the vertebrate nervous system consisting of the brain and spinal cord |
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pns |
subdivision of the nervous system that brings information to the cns |
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autonomic nerves |
serves the internal organs of the body |
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nerve impulse |
message that travels from the dendrites of a neuron to the axon |
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axon |
long nerve fiber that conducts away from the cell body of the neuron |
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dendrite |
the branching extensions of a neuron that receives messages and conducts impulses toward the cell body |
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schwann cell |
large nucleated cells that form myelin around the axons of neurons |
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node of ranvier |
small gap between myelinated segments where axonal membrane is exposed; increase speed of impulses |
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synapse |
the space between two neurons through which neurotransmiters travel |
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receptor |
recieves information about changes in the enviroment (stimuli) |
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effector |
muscles or glands that respond to impulses |
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stimulus |
something that causes a response |
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cell body |
contains major concentration of the cytoplasm and the nucleus of the neuron |
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myelin |
an electrically-insulating phospholipid (fat) layer that surrounds the axons of many neurons |
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reflex |
A relatively simple, involuntary response to a stimulus. |
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resting potential |
the potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse |
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action potential |
change in electrical potential that occurs between the inside and outside of a nerve or muscle fiber when it is stimulated |
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refractory period |
the time after a neuron fires during which a stimulus will not evoke a response |
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saltatory conduction |
transmission of an impulse by jumping |
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neurotransmitter |
a chemical messenger that travels across the synapse from one neuron to the next and influences whether a neuron will generate an action potential(impulse) |
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spinal cord |
part of central nervous system, links brain to rest of body |
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cerebellum |
responsible for balance and coordination, routine movement |
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cerebrum |
the largest part of the brain, controls thinking, reasoning, and memory |
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corpus callosum |
connects the hemispheres; found deep inside cerebrum; allows hemispheres to share information |
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pons |
relay link between brain and spinal cord |
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medulla oblongata |
Regulates ♥ heart rhythm, blood flow, breathing rate,etc. |
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endorphins |
natural neurotransmitters linked to pain control |
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sclera |
Tough, white outer layer of the eye |
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choroid coat |
middle layer of the eye; contains blood vessels |
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retina |
The light sensitive layer of the eye which is composed of receptors (rods and cones). |
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aqueous humor |
anterior cavity of the eye filled with clear, watery fluid |
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vitreous humor |
the clear colorless transparent jelly that fills the posterior chamber of the eyeball |
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nearsightedness |
a condition in which nearby objects are seen more clearly than distant objects |
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farsightedness |
condition in which vision for distant objects is better than for near objects |
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rods |
rod-shaped receptor in the retina of the eye that is sensitive to dim light but not color |
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cones |
Receptor cells in the retina that are sensitive to bright light and produce color vision. |
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pinna |
visible part of the outer ear. It collects sound and directs it into the auditory canal |
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eardrum |
the membrane that seperates the outer ear from the middle ear and that vibrates when sound waves strike it (tympanic membrane) |
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hammer |
the bone attached to the eardrum |
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anvil |
the bone between the hammer and the stirrup |
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stirrup |
a tiny U shaped bone that passes vibrations from the anvil to the cochlea |
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oval window |
membrane that covers opening between middle ear and inner ear |
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cochlea |
a coiled tube that is found in the inner ear and that is essential to hearing |
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semicircular canal |
3 loops of fluid filled tubes that that are attached to to the cochlea; maintains equilibrium |
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olfactory cells |
sensitive nerve cells in nasal passages. |
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autonomic nervous system |
The part of the nervous system that controls involuntary action and responses. |
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eustachian tubes |
tube connecting ear to throat; helps to equalize pressure |
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Parkinson's Disease |
a progressive disease that destroys brain cells and is identified by muscular tremors, slowing of movement, and partial facial paralysis |
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Alzheimer's Disease |
a disease that results in the progressive loss of an individual's memory and mental capacity. |
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ALS |
"Lou Gherig's Disease" - progressive neurological disease in which the motor neurons degenerate to the point of total loss of motor function. The intelligence, memory, and personality is unaffected. |
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Multiple Sclerosis |
disorder in which myelin is destroyed causing loss of motor activity |
