Term
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Definition
| information gathered by the nervous system |
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Definition
| nervous system processes and interprets sensory input and decides what should be done |
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Definition
| the nervous system’s response to the stimulus; done by activating effector organs (muscles and glands) |
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Definition
| most abundant and most versatile; make exchanges between capillaries and neurons, migration of young neurons and in synapse formation; control chemical environment around neurons; mop up leaked potassium ions and recapturing released neurotransmitters |
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Definition
| small ovoid cells with thorny processes; monitor the health of neurons; phagocytize microorganisms and neuronal debris |
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Definition
| squamous or columnar cilitated cells that line the central cavities of the brains and spinal cord; the cilia helps to circulate cerebrospinal fluid |
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Definition
| line up along neuron fibers in the CNS and wrap their processed tightly; forms myelin sheaths |
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Definition
| surround neurons and cell bodies located in the PNS (same as astrocytes in CNS) |
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Definition
| surround and form myelin sheaths around the larger nerve fibers of the PNS (similar to Oligodendrocytes) |
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Term
| SPECIAL CHARACTERISTICS OF NERVE CELLS |
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Definition
1. Extreme longevity
2. Amitotic- can not divide and reproduce
3. High metabolic rate- require abundant supplies of oxygen and glucose |
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Term
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Definition
| also called the perikaryon or soma; major biosynthetic center of a neuron contains the following organelles: |
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Definition
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Definition
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| Bundles of neuron processes |
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Definition
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| Bundles of neuron processes |
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Definition
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Term
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Definition
| main receptor or input regions; convey messages towards the cell body; graded potentials |
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Term
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Definition
| conducting region or the neruron; generates nerve impulses and transmits them typically away from the cell body |
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Term
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Definition
| movement toward the axon terminal; organelles and enzymes needed for synthesis of neurotransmitters |
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Term
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Definition
| - movement away from the axon terminal; organelles being returned to the cell body for recycling and for intracellular communication |
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Term
| Myelin Sheath and Neurilemma |
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Definition
| protects and electrically insulates fibers; increases the speed of transmission of nerve impulses |
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Term
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Definition
| gap in between parts of the myelin sheath |
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Term
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Definition
| regions of the brain containing dense collections of myelinated fibers; fiber tracts |
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Term
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Definition
| contains mostly nerve cell bodies and unmyelinated fibers |
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Term
| Structural classification of neurons |
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Definition
| neurons are grouped according to the number of processes extending from their cell body |
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Term
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Definition
| have three or more processes; most common neuron in humans; major neuron type in the CNS |
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Term
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Definition
| have two processes; an axon and a dendrite; found in some of the special sensory organs such as the retina |
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Term
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Definition
| have a single short process that emerges from the cell body and divides t-like into proximal and distal branches |
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Term
| functional classification of neurons |
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Definition
| neurons are grouped according to the direction in which the nerve impulse travels relative to the CNS |
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Term
| sensory neurons (afferent) |
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Definition
| transmits impulses from sensory receptors in the skin or internal organs toward or into the CNS. All sensory neurons are unipolar and their cell bodies are located in sensory ganglia outside the CNS. |
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Term
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Definition
| carry impulses away from the CNS to the effector organs (muscles and glands) of the body periphery. Motor neurons are multipolar; located in the CNS. |
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Term
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Definition
| lie between motor and sensory neurons and shuttle signals through CNS pathways where intergration occurs; make up 99% of all the neurons of the body; including most of those in the CNS; multipolar |
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Term
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Definition
| the measure of potential energy generated by separated charge |
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Term
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Definition
| the flow of electrical charge from one point to another |
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Term
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Definition
| is the hindrance to charge flow provided by substances through which the current must pass |
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Definition
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Definition
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Term
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Definition
| Current (I)= voltage (v)/resistance (R) |
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Term
| Leakage or nongated channels |
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Definition
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Term
| Chemically gated or ligand-gated channels |
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Definition
| open when the appropriate chemical (neurotransmitter) binds |
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Term
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Definition
| open and close in response to changes in the membrane potential |
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Term
| mechanically gated channels |
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Definition
| open in response to physical deformation of the receptor |
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Term
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Definition
| electrical and concentration gradient together; Ion flow along electrochemical gradients underlies all electrical phenomenon in neurons |
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Term
| RESTING MEMBRANE POTENTIAL |
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Definition
| a difference in K+ and Na+ concentrations inside and outside cells; differences in permeability of the plasma membrane of these ions |
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Term
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Definition
| a reduction in the membrane potential: the inside of the membrane becomes less negative or moves closer to zero |
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Term
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Definition
| - occurs when the membrane potential becomes more negative |
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Term
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Definition
| are short lived localized changes in membrane potential; can be either depolarization or hyperpolarization |
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Term
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Definition
| - a brief reversal of membrane potential with a total amplitude change of about 100 mV; a depolarization phase is followed by a repolarization phase and often a short period of hyperpolarization; an influx of Na+ leaves for a temporary positive charge in axon |
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Term
| Absolute refractory period |
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Definition
| the period from the opening of the Na+ channels until the Na+ channels begin to reset to their original resting state |
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Term
| relative refractory period |
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Definition
| the interval following the absolute refractory period; repolarization is occurring |
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