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Neurons. Functional Classification of Neurons. Sensory (Afferent) Neurons Motor (Efferent) Neurons Association Neurons (Interneurons). Sensory (Afferent) Neurons. Neurons carrying impulses from sensory receptors to the CNS. Found in ganglion outside the CNS.
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Functional Classification of Neurons • Sensory (Afferent) Neurons • Motor (Efferent) Neurons • Association Neurons (Interneurons)
Sensory (Afferent) Neurons • Neurons carrying impulses from sensory receptors to the CNS. • Found in ganglion outside the CNS. • Dendrite endings associated with specialized receptors.
Specialized Receptors • Free nerve endings (pain & temperature) • Meissner’s corpuscle (touch receptor) • Lamellar corpuscle (deep pressure receptor) • Golgi tendon organ (proprioceptor) • Muscle spindle (proprioceptor) Proprioceptor – detect the amount of stretch, or tension, in skeletal muscles, their tendons, and joints
Motor (Efferent) Neurons • Neurons carrying impulses from the CNS to the viscera and/or muscles and glands. • Cell bodies are always located in the CNS.
Association Neurons or Interneurons • Connect the motor and sensory neurons in a neural pathway. • Cell bodies are always located in the CNS. http://img.tfd.com/dorland/thumbs/interneuron.jpg
Structural Classifications of Neurons • Multipolar Neuron • Bipolar Neuron • Unipolar Neuron
Multipolar Neurons • Most common structural type. • Motor neurons and association neurons.
Bipolar Neurons • Rare • Found in ears and eyes • Sensory receptor cells.
Unipolar Neurons • Single short process emerging from cell body. • Divides into proximal and distal processes. • Dendrites at the end of proximal process. • Neurons in PNS ganglia.