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The Nervous System

The Nervous System. functions. Detects changes in the body Make decisions Stimulate muscles or glands to respond Works by sending an electrical signal known as an action potential through the cells of the nervous system, which are called neurons. The Divisions. Central nervous system.

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The Nervous System

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  1. The Nervous System

  2. functions • Detects changes in the body • Make decisions • Stimulate muscles or glands to respond • Works by sending an electrical signal known as an action potential through the cells of the nervous system, which are called neurons

  3. The Divisions

  4. Central nervous system • Abbreviated CNS • Consists of Brain and Spinal Cord

  5. Peripheral nervous system • Abbreviated PNS • Consists of cranial and spinal nerves • Further divided into Sensory Division and Motor Division

  6. Sensory Division • Signals sent to the CNS from PNS • Various senses – sight, hearing, touch (temperature, pressure, etc.) , taste, smell

  7. Motor Division • Signals sent from CNS to PNS • Carry out effectors- actions that result in an effect happening • Skeletal, smooth, cardiac muscle movement and glandular secretion • Further divided into Somatic Nervous System and Autonomic Nervous System

  8. Somatic Nervous system • Voluntary effectors, such as breathing and skeletal muscle contraction

  9. Autonomic nervous system • Involuntary effectors, such as heartbeat, smooth muscle contraction, secretion of hormones and enzymes

  10. neuron • Cell Body • Nucleus • Dendrites • Axon hillock • Axon • Myelin Sheath • Schwann Cells • Nodes of Ranvier • Axon Terminal • Synaptic Knob

  11. Myelin • Myelinated neurons appear white • Unmyelinated neurons appear gray • 3 purposes • Protects axon • Insulates axon • Speeds rate of transmission • Schwann Cells enclose, but do not wrap around myelin sheath

  12. Types of neurons • Multipolar – found mostly in the brain and spinal cord • Bipolar – found in eyes, nose, and ears • Unipolar – connect PNS with CNS

  13. Other types of neurons • Sensory Neurons – Sensory Divison • Interneurons – Relays info between neurons in brainand spinal cord • Motor Neuron – Motor Division

  14. Neuroglia • Cells of the nervous system that perform other functions apart from transmitting impulses

  15. Neuroglia of cns • Astrocytes – structural support, mop up excess ions and neurotransmitters, induce synapse formation • Oligodendrocytes – creates myelin • Microglia – structural support and phagocytosis • Ependyma – forms a membrane for which substances can diffuse from the fluid of the brain to the cerebrospinal fluid

  16. Neuroglia of pns • Schwann Cells – protect axons, speed neurotransmition • Satellite Cells – Support ganglia (clusters of neurons)

  17. synapse • Presynaptic neuron – the neuron carrying the message • Postsynaptic neuron – the neuron receiving the message • Synaptic Cleft – separates the 2 cells • Synaptic knob of presynaptic neuron connected with dendrite or cell body of postsynaptic neuron

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