Nervous System Research Paper Essay Example for Free

Nervous musical arrangement Research Paper EssayAs a result of the differences in charges, an electro-chemical difference of about -70 millivolts occurs. The sodium-potassium pump, a system which removes sodium ions from inside the cubicle and draws potassium ions back in, maintains the electrical balance of the resting kiosk. Since the cell has to do work to maintain the ion concentration, ATP molecules are used to provide the necessary energy. Once a tinder impulse is generated, the permeability of the cell membrane changes, sodium ions fly the coop into, and potassium ions flow out of, the cell. The flow of ions causes a reversal in charges, with a positive charge now occurring on the interior of the cell and a negative charge on the exterior. The cell is said to be depolarized, resulting in an action authorisation causing the nerve impulse to move along the axon. As depolarization of the membrane proceeds along the nerve, a series of reactions start with the opening and closing of ion gates, which allow the potassium ions to flow back into the cell and sodium ions to move out of the cell.The nerve becomes polarized again since the charges are restored. Until a nerve becomes repolarized it cannot respond to a invigorated stimulus the time for recovery is called the refractory period and takes about 0. 0004 of a second. The more deep the stimulus, the more frequent the firing of the nerve cell. When the impulse reaches the end of the axon, it causes the release of chemicals from small vesicles called neuro lendters which diffuse across the synaptic gap, the small space among the axon and receptors in the dendrites.There is no physical contact between axons and dendrites (except in electrical transmission, usually found in invertebrates) which takes place through gap junctions. The subject of answer by the receiving cell may be excitatory or inhibitory depending upon a number of factors including the type of neurotransmitters involved. All nerve impulses are the same whether they originate from the ear, heart, or stomach. How the impulse is interpreted is the job of the primaeval unquiet system. A blow to the head near the optic center of the brain produces the same results as though the impulse had originated in the eyes.The neurons are the functional units of the nervous system through which coordination and control in organisms is executed. Resources Books BSCS Revision Team. Biological Science A Molecular Approach. Lexington, MA D. C. Heath Co. , 1990. Campbell, Neil A. Biology. Menlo Park, CA Benjamin/Cummings, issue Company, 1987. Carey, Joseph, ed. Brain Facts A Primer on the Brain and the Nervous System. Washington, DC Society for Neuroscience, 1993. Curtis, Helena, and N. Sue Barnes. Biology. fifth ed. New York Worth Publishers, 1989.Holtzman, Eric, and Alex B. Novikoff. Cells and Organelles. Philadelphia Saunders College Publishing, 1984. Kuffler, Stephen W. , and John G. Nicholls. From Neuron to Brain. Sunder land, MA Sinauer Associates, 1976. Pine, Maya, ed. Seeing, Hearing and Smelling The World. Chevy Chase Howard Hughes medical Institute, 1995. Purves, Dale. Body and Brain A Trophic Theory of Neural Connections. Cambridge Harvard University Press, 1988. Raven, Peter H. , and George B. Johnson. Biology. 3rd ed. St. Louis Mosby Year Book, 1992. Towle, Albert. youthful Biology.Austin, TX Holt, Reinhart, and Winston, 1991. KEY TERMS Action electromotive force A transient change in the electrical potential across a membrane which results in the generation of a nerve impulse. Axon The threadlike labor of a neuron that carries an impulse away from the cell body of the neuron. Dendrites Branched structures of nerve cell bodies which beat impulses from axons and carry them to the nerve cell body. Depolarization A tendency of a cell membrane when affect to allow charged (ionic) chemical particles to enter or leave the cell.This favors the neutralization of excess positive or negative part icles within the cell. Ganglion Cluster of nerve cell bodies. In vertebrates, found outside of the interchange nervous system and act as relay stations for impulses. In invertebrates, act as a central control. Homeostasis The internal stability of an organism. Myelin A multilayered membrane system of a Schwann cell that wraps around an axon. do up of lipoproteins that act as insulators in speeding up the transmission of nerve impulses. Nerve Bundles of axons in a connective tissue sheath which follow a specific path. Nerve impulse A transient change in the electro-chemical nature of a neuron. Neuron Cell specialized to receive and transmit impulses functional unit of the nervous system. Neurotransmitter A chemical released at the end of an axon which is picked up by receptors such as dendrites, muscles, or secretory cells. Polarized Two different charges on either side of a membrane caused by a difference in the distribution of charges in resting nerve cells maintained by the sodi umpotassium pump.Reflex A rapid response to a stimulus that involves a sensory and motor neuron and may involve an interneuron. Refractory period Recovery period for the neuron in which no new impulse can be generated it cannot respond to a stimulus until it is repolarized. Sodium-potassium pump A special carry-over protein in the membrane of cells that moves sodium ions out and potassium ions into the cell against their concentration gradients. Synapse Junction between cells where the counterchange of electrical or chemical information takes place.