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Sympathetic Nervous System definitions

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  • Sympathetic Nervous System
    Activates during stress, increasing heart rate, blood pressure, and airflow, while decreasing gastrointestinal activity.
  • Fight or Flight Response
    A physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival.
  • Preganglionic Fiber
    The short nerve fiber that originates in the spinal cord and synapses in a ganglion.
  • Postganglionic Fiber
    The long nerve fiber that extends from a ganglion to the target organ.
  • Sympathetic Trunk
    A bundle of nerve fibers running parallel to the spinal cord, involved in transmitting nerve impulses.
  • Ganglia
    Structures acting as relay points where nerve impulses can synapse or pass through.
  • Splanchnic Nerves
    Nerves that bypass the sympathetic trunk to synapse in collateral ganglia near abdominal organs.
  • Adrenal Medulla
    Part of the sympathetic nervous system, secreting adrenaline and noradrenaline for the fight or flight response.
  • Vasoconstriction
    The narrowing of blood vessels, reducing blood flow to certain areas like the stomach or intestines.
  • Vasodilation
    The widening of blood vessels, increasing blood flow to skeletal muscles during stress.
  • Arrector Pili Muscles
    Tiny muscles around hair follicles that contract to cause goosebumps.
  • Dual Innervation
    Most organs receive nerve fibers from both sympathetic and parasympathetic divisions.
  • White Ramus Communicans
    Carries preganglionic fibers from the spinal nerve to the sympathetic ganglia.
  • Gray Ramus Communicans
    Carries postganglionic fibers from the ganglia back to the spinal nerve.
  • Collateral Ganglion
    Ganglia located closer to effector organs where splanchnic nerves synapse.