Autonomic Nervous System

Cards (23)

  • Sympathetic Nervous System (SNS)
    • Originates from the thoracic and lumbar regions of the spinal cord (thoracolumbar outflow)
    • Preganglionic neurons exit the spinal cord and synapse with postganglionic neurons in ganglia located near the spinal cord (paravertebral ganglia) or close to the target organ (prevertebral ganglia)
  • Sympathetic Nervous System (SNS)
    • Associated with the "fight or flight" response
    • Increases heart rate, dilates airways, redirects blood flow to muscles, and stimulates the release of glucose for energy
  • Parasympathetic Nervous System (PNS)
    • Originates from the brainstem and the sacral region of the spinal cord (craniosacral outflow)
    • Preganglionic neurons exit the brainstem or sacral spinal cord and synapse with postganglionic neurons in ganglia located near or within the target organs
  • Parasympathetic Nervous System (PNS)
    • Associated with the "rest and digest" response
    • Conserves energy by slowing heart rate, stimulating digestion, and promoting relaxation
  • Functions of the Autonomic Nervous System (ANS)
    • Maintenance of homeostasis
    • Contraction and relaxation of smooth muscle
    • All exocrine and some endocrine secretions
    • Heart rate and contraction
    • Metabolism (in the liver and skeletal muscle)
  • Sympathetic Nervous System (SNS)
    Responsible for the "fight or flight" response, which prepares the body for action in response to stress or danger
  • Factors that activate the Sympathetic Nervous System (SNS)
    • Environmental changes
    • Emotional stress and anxiety
    • Exercise
    • Dehydration
    • Some disease states
  • Parasympathetic Nervous System (PNS)
    The "rest and digest" system, which helps conserve energy and promotes relaxation
  • Acetylcholine (ACh)

    Neurotransmitter for both the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PNS)
  • Muscarinic Receptors

    • ACh binds to muscarinic receptors, which are G protein-coupled receptors
    • Activation of muscarinic receptors can lead to changes in ion flow across the cell membrane, modulation of enzyme activity, and changes in gene expression
  • Nicotinic Receptors
    • ACh binds to nicotinic receptors, which are ligand-gated ion channels
    • Activation of nicotinic receptors leads to the influx of ions, such as sodium and potassium, which can depolarize the cell membrane and trigger an action potential
  • Adrenergic Receptors
    • Norepinephrine (NE) and Epinephrine (E) bind to adrenergic receptors, which are G protein-coupled receptors
    • Activation of adrenergic receptors can lead to changes in intracellular signaling pathways, resulting in various physiological responses, such as smooth muscle contraction, glycogenolysis, and changes in heart rate
  • Physiological responses associated with Sympathetic Nervous System (SNS) activation
    • Increased heart rate and contractility
    • Pupil dilation
    • Relaxation of eye ciliary muscles
    • Decreased salivary gland secretion
    • Bronchodilation
    • Inhibition of gastrointestinal motility and secretion
    • Inhibition of bladder contraction
    • Increased speed of skeletal muscle contraction, increased muscle mass, and glycogenolysis
  • Physiological responses associated with Parasympathetic Nervous System (PNS) activation
    • Decreased heart rate, automaticity, and contractility
    • Pupil constriction
    • Accommodation of the eye lens
    • Increased salivary gland secretion
    • Bronchoconstriction
    • Enhanced digestion and absorption of nutrients
    • Increased bladder emptying
  • Adrenergic Agonists (Sympathomimetics)

    Drugs that mimic the effects of norepinephrine and epinephrine by activating adrenergic receptors (α and β receptors)
  • Adrenergic Agonists (Sympathomimetics)
    • Epinephrine
    • Dobutamine
    • Albuterol
  • Adrenergic Antagonists (Sympatholytics)
    Drugs that block the effects of norepinephrine and epinephrine by binding to adrenergic receptors
  • Adrenergic Antagonists (Sympatholytics)
    • Propranolol
    • Prazosin
  • Muscarinic Agonists (Cholinergic Agonists)

    Drugs that mimic the effects of acetylcholine by activating cholinergic receptors (muscarinic and nicotinic receptors)
  • Muscarinic Agonists (Cholinergic Agonists)

    • Bethanechol
    • Pilocarpine
  • Muscarinic Antagonists (Anticholinergic Agents)

    Drugs that block the effects of acetylcholine by binding to cholinergic receptors
  • Muscarinic Antagonists (Anticholinergic Agents)

    • Atropine
    • Scopolamine
  • Ganglionic Blockers
    Drugs that block transmission in autonomic ganglia, leading to widespread autonomic effects