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Neural and Hormonal System . Mod 3 Part 1. Stinger . 1.) What do you know about how messages travel from the brain to the rest of the body? 2.) Do you know any names of hormones or neurotransmitters? (List if you do.) . Systems. Systems are often part of larger systems
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Neural and Hormonal System Mod 3 Part 1
Stinger • 1.) What do you know about how messages travel from the brain to the rest of the body? • 2.) Do you know any names of hormones or neurotransmitters? (List if you do.)
Systems • Systems are often part of larger systems • Bio-psycho-social system: your body, mind, and society • Biological psychologists: psychologists who study links between biology, behavior, and mental processes • Sleep and dreams • Depressionand schizophrenia • Hunger and sex • Stress and disease • Information systems of humans and other animals are similar
Neurons and neural impulsess • What are neurons and how do they trasmit information? • Neurons • Nerve cells • Building blocks of the nervous system • Cell body, axon and dendrite • Denfrtie: bushy fibers that receive information • Axon: fibers that transmit information to neurons, muscles, and glands • Can be very long • Motor neurons like giant redwoods • Myelin sheath • Insulates axons of some neurons • Speeds impulses • Prevents misfire or cross fire • Multiple Sclerosis is a disease of myelin degeneration • Slower than electricity, but measured in microseconds
Action Potential • Neurons fire when • Receives signal from sense receptors stimulated by pressure, heat or light • Stimulated by chemical messages from neighboring neurons • Action potential: brief electrical charge that travels down the axon • Based on exchange of ions • Negative inside/positive outside • Resting potential • Selectively permeable: only lets certain transmitters in through certain gates • Firing involves the first bit of the axon to open, then the positively charged particle moves down the axon gate by gate • Depolarization area by area • Refractory period • Axon rests, pushing positively charged particles back out • It can fire again only after resting
Chemical Reactions • Excitatory chemicals push neurons accelerator • Inhibitory chemicals keep neuron from firing • Threshold: minimum intensity to cause neuron to fire • Excitatory chemicals must overcome inhibitory chemicals • Action potential moves down the axon and can trigger multiple other reactions • More excitatory chemicals does not equal a bigger reaction, but it may cause more neurons to fire.
Stop and Review • What are the parts of a neuron? • How does chemical information move down an axon? • What is necessary to send a chemical message down an axon? • What is a refractory period? • How do neurons communicate with each other?
Homework • Complete Charts • Neuron • Synapse • Axon • Action Potential • Read Pages 54-64