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| state of relative stability within the body |
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| in animals, system made up of cells and organs that let an animal detect changes and respond to them; made up of the brain and spinal cord, as well as the nerves that emerge from them and connect them to the rest of the body |
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| network of nerves that includes the brain and spinal cord; integrates and processes information sent by nerves |
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| nerve cell; the structural and functional unit of the nervous system, consisting of a necleus, cell body, dendrites, acons, and myelin sheath: specialized to respond to physical and chemical stimuli, to conduct electrochemical signals, and to release chemicals that regulate various body processes |
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| peripheral nervous system |
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| network of nerves that carry sensory messages to the CNS and send info from the CNS to the muscles and glands; consists of the autonomic and somatic system |
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| support cell of the nervous system that nourishes neurons (nerve-impulse conducting cells), removes their wastes, defends against infection, and provides a supporting framework for all the nervous system tissue |
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| message pathway of the nervous systeml made up of many neurons grouped into bundles and surrounded by protective connective tissue |
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| simple connection of neurons that results in a reflex action in response to a stimulus |
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| short, branchin terminal on a nerve cell (neuron) that recieves signals from other neurons or sensory receptors and relays the impulse to the cell body; numerous and highly branches |
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| the main part of a neuron, containing the nucleus and other organelles and serving as the site of the cell's metabolic reactions; processes input from the dendrites and, if the input recieved is large enough, relays it to the axon, where an impulse is initiated |
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| long, cylindrical extension of a neuron's cell body that can range from 1 mm to 1 m in length; transmits impulses away from the cell body along its length to the next neuron |
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| the fatty, insulating later around the axon of a nerve cell, composed of Scwann cells; protets myelinated neurons and speeds the rate of nerve impulse transmission |
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| a type of insulating glial cell that wraps around the acon of a neuron, creating a myselin sheath |
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| electrical charge seperatoin across a cell membrane; a form of potential energy |
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| resting membrane potential |
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| potential differences across the membrane in a resting neuron |
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| lowering the membrane potential of the cell below its equilibrium value; in nerves, the process of generating a resting membrane potential of -70mV |
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| sodium-potassium exchange pump |
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| system involving a carrier protein in th eplasma membrane that uses the energy of ATP to transport sodium ions out of and potassium ions into animal cells; important in nerve and muscle cells |
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| in a neuronal membrane, reducing a membrane potential to less than the resting potential of -70mV |
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| gap in the myelin sheath insulating the acon of myelinated nerve cell; the membrane of the axon is exposed and action potentials occur only at these nodes; nerve impulses jimp from one node of Ranvier to the next |
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| in an acon, the change in charge that occurs when the gates of the K+ channels close and the gates of the Na+ chennels open after a wave of depolarization is triggered |
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| in a neuronal membrane, the minimum change in the membrane required to generate an action potential; usually -55mV |
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| return of a nerve to its resting potential following depolarization |
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| the brief time (a few milliseconds) between the triggering of an impulse along an acon and the acon's readiness for the next impulse; duing this time, the axon cannot transmit an impulse |
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| junction between two neurons or between a neuron and an effector (muscle or gland) |
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| synapse between a motor neuron and a muscle cell |
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| chemical messenger secreted by neurons to carry a neural signal from one neuron to another, or from a neuron to an effector, such as a gland or muscle fibre |
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| the primary neurotransmitter of both the somatic nervous system and the parasympathetic nervous system |
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| enzyme that breaks fown the neurtransmitter acetylchoine in the synapse |
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what are the two main branches of the nervous system? |
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| two main branches of the Peripheral Nervous system? |
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| two main branches of the Motor (efferent) neurons? |
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| Two main branches of the Autonomic Nervous system? |
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| Two main branches of Central Nervous system? |
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| What is the structure of a typical neuron? |
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