Somatic Nervous System

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Somatic Nervous System

• Contraction of _________ muscles
• Skeletal muscle somatic effector
• All _____________ motor pathways outside of CNS
• Neurotransmitter ______

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Reflexes

• All voluntary motor pathways outside of CNS
• Reflexes
• Action resulting from nerve impulse passing over
  a reflex arc
• Predictable response to stimuli
• ____________ Reflex
• Visceral
• Contraction of smooth or cardiac muscle
• Secretion of glands
• ____________ Reflex
• Contraction of skeletal muscles

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Somatic Reflexes

• Contraction of skeletal muscles
• Reflexes deviate from normal in certain
  conditions
• Reflex testing is valuable diagnostic tool
• Patellar Reflex extension of lower leg
• Achilles Reflex extension of foot
• ____________________ Reflex extension of big toe
• Present until age 1.5
• If present after, indicates damage to
  corticospinal fibers
• Plantar Reflex flexion of all toes and slight
  turning in of foot
• Corneal Reflex wink when touch cornea
• Abdominal Reflex stroke side of abdomen causes
  drawing in of abdominal wall

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Knee-Jerk (Patellar) Reflex
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Autonomic Nervous System

• ________________/Visceral body functions
• Cardio, resp, dig, urogen
• Maintain homeostasis by regulating heartbeat,
  smooth muscle contraction, glandular secretions
• Conduct impulses from CNS to autonomic effectors
• Two divisions
• Sympathetic
• Parasympathetic

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Autonomic Conduction Pathway
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Parasympathetic Nervous System
Sympathetic Nervous System

• Feed-or-Breed
• Rest-and-Repose
• Counteracts Sympathetic

• Fight-or-Flight
• Allows body to function under stress

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ANS Neurotransmitters

• Norepinephrine (adrenaline)
• ________________ fibers
• release norepinephrine in postsynaptic
  sympathetic neurons
• Acetylcholine (ACh)
• ________________ fibers
• release ACh in presynaptic sympathetic neurons
• release ACh in pre and post parasympathetic
  neurons

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Norepinephrine

• Affects visceral effectors by binding to
  adrenergic receptors
• Alpha receptor blood vessels __________
• Beta receptor blood vessels ____________
• Inhibiting action of norepinephrine
• MAO (monoamine oxidase) enzyme that breaks up
  norep that are taken up by synaptic knobs

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ACh

• Binds to cholinergic receptors
• Nicotinic receptors
• Muscarinic receptors
• Inhibiting action of Ach
• acetylcholinesterase

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