THeNervousSystem - Chapter 4 The Nervous System A Basic...

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Unformatted text preview: Chapter 4 The Nervous System: A Basic Blueprint • Function of a nervous system is to gather and process information, produce responses to stimuli, and coordinate the workings of different cells. • CNS – receives, processes, interprets, and stores incoming sensory information – information about tastes, sounds, smells, color, pressure on the skin, the state of internal organs. • Spinal Cord – extension of the brain. Bridge between the brain and the parts of the body below the neck. • Spinal Reflexes – automatic, require no conscious effort. (hot iron) • Peripheral Nervous System – handles the central nervous system’s input and output. Includes sensory and motor nerves • Somatic Nervous System – skeletal nervous system, consists of nerves that are connected to sensory receptors. (feel a bug on arm) • Automatic Nervous System – regulates functioning of blood vessels, glands, and internal (visceral) organs such as the bladder, stomach, and heart. (crush ! fast heart beat, sweaty palms) o Sympathetic Nervous System – accelerator of car, mobilizing the body for action and output of energy. (blush, sweat, and breathe deeply) o Parasympathetic Nervous System – like the brake. Slow things down and keep them running smoothly, enables the body to conserve and store energy. Communication in the Nervous System • Neurons – nerve cells, brain’s communication specialists, transmitting information to, from, and within the CNS. • Glia – glial cells, support, nuture, and insulate neurons. Remove debris • Dendrite – branch of a tree, act like antennas, receiving messages from other neurons and transmits those messages toward the cell body. • Cell Body – contains the biochemical machinery for keeping the neuron alive and determines whether or not the neuron will fire. • Axon – transmits messages away from the cell body to other neurons or to muscle or gland cells. Often divide into branches called axon terminals • Myelin Sheath – fatty material surrounding the axon. Prevents messages from adjacent cells to interfere with each other. • Nodes – constrictions in the myelin sheath. • Synapse – the site where transmission of a nerve impulse from one nerve cell to another occurs; it includes the axon terminal, the synaptic cleft, and receptor sites in the membrane of the receiving cell. • Action Potential – a brief change in electrical voltage that occurs between the inside and outside of an axon when a neuron is stimulated; it serves to produce an electrical impulse • Neurotransmitter – a chemical substance that is released by a transmitting neuron at the synapse and that alters the activity of a receiving neuron. • Synaptic vesicles – tiny sacs in the tip of the axon terminal • Neurogenesis – the production of new neurons from immature stem cells. ...
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