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Why do animals need a nervous system?

Why do animals need a nervous system?. Because the world is always coming at you! Take in information Regulation. Remember… think about the bunny…. Poor bunny !. cerebrum. cerebellum. spinal cord. cervical nerves. thoracic nerves. lumbar nerves. femoral nerve. sciatic nerve.

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Why do animals need a nervous system?

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  1. Why do animals need a nervous system? • Because the world is always coming at you! • Take in information • Regulation Remember…think aboutthe bunny… Poor bunny!

  2. cerebrum cerebellum spinal cord cervical nerves thoracic nerves lumbar nerves femoral nerve sciatic nerve tibial nerve Nervous System • Central nervous system • CNS • brain & spinal chord • Peripheral nervous system • nerves from senses • Take in info from environment • nerves to muscles • Allow for response

  3. Nervous cells • Neuron • a nerve cell signal direction dendrites cellbody nucleus signal direction ONE WAY axon terminal branches synapse (space)

  4. 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 1 millisecond response time

  5. Myelin coating - lipid signal direction • Axon coated with insulation made of myelin cells • speeds signal • signal hops from node to node • 330 mph vs. 11 mph • Multiple Sclerosis • immune system (T cells) attacks myelin coating • loss of signal

  6. Synapse Junction between nerve cells • 1st cell releases chemical to trigger next cell – neurotransmitters • proteins – remember 3-D shape?? • where drugs affect nervous system synapse • Drugs – • 1. block receptor sites on receiving neuron • Bind with neurotransmitter to change shape • Prevent release of neurotransmitter

  7. myelin axon vessicle terminal branch protein synapse exocytosis (active transport) dendrite channel protein Mitochondia – R – provide ATP

  8. 3 Types of neurons sensory neuron (from senses) receive stimulus interneuron (CNS -brain & spinal chord) motor neuron (to effector – muscle/gland) produces response

  9. Human brain

  10. Primitive brain • The “lower brain” • medulla oblongata • basic body functions • breathing, heart, digestion, swallowing, vomiting • homeostasis • cerebellum • coordination of movement and balance

  11. Higher brain • Cerebrum • 2 hemispheres • left = right side of body • right = left side of body • Corpus callosum • connection between 2 hemispheres

  12. 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, emotions, multi-tasking

  13. Simplest Nerve Circuit – Reflex Arc • Reflex, or automatic response • signal only goes to spinal cord - FASTER • advantage • essential actions • don’t need to think or make decisions about (automated) • blinking • balance • pupil dilation • startle – “fight or flight”

  14. Reflex ARC

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