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Nervous System AP Biology 2003- Why do animals need a nervous system? What characteristics do animals need in a nervous system? fast accurate reset quickly Remember… Poor thinkbunny! about the bunny… Regents Biology 2003- Nervous System cerebrum cerebellum spinal cord Central nervous system brain & spinal chord Peripheral nervous system nerves from senses nerves to muscles cervical nerves thoracic nerves lumbar nerves femoral nerve sciatic nerve tibial nerve Regents Biology 2003- Nervous system cells Neuron signal direction a nerve cell dendrites cell body axon Regents Biology signal direction synapse 2003- Fun facts about neurons Most specialized cell in animals Longest cell blue whale neuron 10-30 meters giraffe axon 5 meters human neuron 1-2 meters Nervous system allows for 1Regents millisecond Biologyresponse time 2003- Myelin sheath signal direction Axon coated with insulation made of myelin cells speeds signal signal hops from node to node Multiple Sclerosis immune system (T cells) attacks myelin sheath Regents loss ofBiology signal 330 mph vs. 11 mph myelin sheath 2003- Synapse Junction between nerve cells 1st cell releases chemical to trigger next cell this is where drugs affect nervous system Synapse Regents Biology 2003- Neurotransmitter Chemical messenger that transmits a signal from a nerve cell to a receptor Receptor – another nerve cell a muscle an organ Regents Biology Types of neurons sensory neuron (from senses) interneuron (brain & spinal chord) Regents Biology motor neuron (to muscle) Human brain Regents Biology Primitive brain The “lower brain” medulla oblongata pons cerebellum Functions basic body functions breathing, heart, digestion, swallowing, vomiting homeostasis coordination of movement Regents Biology Higher brain Cerebrum hemispheres left = right side of body right = left side of body Corpus callosum major connection between 2 hemispheres Regents Biology Division of Brain Function Left hemisphere “logic side” language, math, logic operations, vision & hearing details fine motor control Right hemisphere “creative side” pattern recognition, spatial relationships, non-verbal ideas, emotional processing, parallel processing of information Regents Biology 2003- Cerebrum specialization Regions of the cerebrum are specialized for different functions Lobes frontal temporal occipital parietal Regents Biology Limbic system Controls basic emotions (fear, anger), involved in emotional bonding, establishes emotional memory Regents Biology 2003- Simplest Nerve Circuit Reflex, or automatic response rapid response automated signal only goes to spinal cord no higher level processing advantage essential actions don’t need to think or make decisions about blinking balance pupil dilation startle Regents Biology Eye Blink or Pain Withdrawal Reflex Gray Interneuron matter White matter Stimulus Sensory neuron Receptor in skin Motor neuron Spinal cord Regents Biology Effector (muscle) cerebrum cerebellum spinal cord cervical nerves thoracic nerves lumbar nerves femoral nerve Any Questions?? sciatic nerve tibial nerve AP Biology 2003-
