Question | Answer |
Neuron | or nerve cell; a specialized cell that conducts impulses and is the functional unit of the nervous system; is made up of the cell body and its processes |
Soma | the body of an organism |
Dendrite | branching extensions of neurons that carry electrical signals to the cell body; the receptive portion of a nerve cell |
Synapse | the region of communication between neurons; the junction across which a nerve impulse passes from an axon terminal to a neuron, muscle cell, or gland cell. |
Multipolar neuron | possesses a single (usually long) axon and many dendrites, allowing for the integration of a great deal of information from other neurons |
Bipolar neuron | specialized sensory neurons for the transmission of special senses; has two extensions |
Unipolar neuron | only one protoplasmic process (neurite) extends from the cell body |
Anaxonic neuron | a neuron with multiple dendrites, no axons |
Schwann Cell | wrap around axons of motor and sensory neurons to form the myelin sheath; principal glia of the peripheral nervous system |
Myelin sheath | a electrically insulating material that forms a layer, usually around only the axon of a neuron |
Electrical potential | the potential energy of a unit positive charge at a point in an electric field that is reckoned as the work which would be required to move the charge to its location in the electric field from an arbitrary point having zero potential |
Current | a flow of electric charge (a phenomenon) or the rate of flow of electric charge a quantity; is typically carried by moving electrons |
Polarized | there are fewer positive ions sitting on the inner face of the neruron’s plasma membrane than there are on its outer face in the tissue fluid that surrounds it |
Neurotransmitter | chemicals which transmit signals from a neuron to a target cell across a synapse |
Dopamine | neurotransmitter that is linked to adrenaline; a monoamine C8H11NO2 that is a decarboxylated form of dopa and occurs especially as a neurotransmitter in the brain and as an intermediate in the biosynthesis of epinephrine |
Serotonin | active as a neurotransmitter and in vasoconstriction, stimulation of the smooth muscles, and regulation of cyclic body processes (involved in depression); is a powerful vasoconstrictor and is found especially in the brain, blood serum |
Somatic reflex | include all reflexes that stimulate the skeletal muscles |
Visceral reflex | a reflex mediated by autonomic nerves and initiated in the viscera |
Meninges | the membranes that cover the brain and spinal cord |
Dura mater | the outermost and toughest of the three membranes (meninges) covering the brain and spinal cord |
Gray matter | the gray area of the central nervous system; contains unmyelinated nerve fibers and nerve cell bodies |
White matter | white substance of the central nervous system; the myelinated nerve fibers |
Cerebrum | the largest part of the brain; consists of right and left cerebral hemispheres |
Cerebellum | part of the hindbrain; involved in producing smoothly coordinated skeletal muscle activity |
Gyrus | an outward fold of the surface of the cerebral cortex |
Sulcus | a furrow on the brain; less deep than a fissure |
Brain stem | the portion of the brain consisting of the medulla, pons, and midbrain |
Cortex | the outer surface layer of an organ |
Blood-brain barrier | a mechanism that inhibits passage of materials from the blood into brain tissues |
Medulla oblongata | the most inferior part of the brain stem |
Thalamus | a mass of gray matter in the diencephalon of the brain |
Hypothalamus | the region of the diencephalon forming the floor of the third ventricle |
Occipital lobe | the posterior lobe of each cerebral hemisphere; interprets visual sensory impulses |
Parietal lobe | the portion of each cerebral hemisphere concerned with the perception and interpretation of sensations of touch, temperature, and taste and with muscular movements; language |
Frontal lobe | the largest and most anterior part of each cerebral hemisphere; responsible for control of skilled motor activity, including speech, the mood, and the ability to think |