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AS- BIOLOGY Nervous system.


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A simple presentation that covers human nervous system biology

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AS- BIOLOGY Nervous system.

  1. 1. The Human Nervous System
  2. 2. Neuron- A Nerve Cell  Cell body Contains the nucleus and other organelles Dendrites Receive stimuli Conduct impulses toward the cell body Axon Carries impulses away from the cell body
  3. 3. Axon Structure Myelin sheath Insulating coat of plasma membranes Sections of sheath are called “Schwann Cells” Unmyelinated axons carry impulses much slower than myelinated axons Nodes of Ranvier Bare axonal membrane between Schwann cells
  4. 4. The Synapse Synapse The gap between nerve cells Neurotransmitter Chemicals that carry nerve signals across the synapse
  5. 5. Reflex Arc The reflex arc responds to a stimulus without the immediate involvement of the brain
  6. 6. Central Nervous System (CNS) • Brain • Spinal Cord
  7. 7. Cerebrum Directs voluntary movement Sensory processing Language and communication Learning and memory
  8. 8. Cerebellum Regulates sense of balance Coordinates voluntary muscle movement
  9. 9. Medulla Oblongata Breathing Heart rate Blood pressure Swallowing and digestion
  10. 10. Peripheral Nervous System (in blue)
  11. 11. Peripheral Nervous System • Sensory Division – Bring information to the CNS • Motor Division – Carries signals away from the CNS • Somatic (voluntary) nervous system controls skeletal muscle action • Autonomic nervous system (involuntary) controls organ systems and smooth muscle
  12. 12. Divisions of the Autonomic Nervous System • Sympathetic – Stress responses (Fight or Flight) • Pupils dilate • Mouth dries up (saliva decreases) • Heart rate increases • Blood flow to skeletal muscle increases • Parasympathetic – Relaxation response • Heart rate slows • Pupils constrict • Stimulates salivation • Digestive processes stimulated