Pharm Review Ch 13: Peripheral Nervous System

  1. Baroreceptor reflex
    • the most important feedback loop of the autonomic system
    • regulates the blood pressure
    • found in carotid and aortic arch
  2. autonomic tone
    • day to day influence exerted by the autonomic nervous system
    • provides basal level contol over which reflex regulation is superimposed
  3. basal level
    • the division of the nervous system that takes predominance in an organ when the organ is innervated by both the sympathetic and parasympathetic system
    • most organs have the parasympathetic system as basal level/tone (EXCEPT the vascular system which is only innervated by sympathetic nervous system)
  4. 2 sites that drugs work on in parasympathetic nervous system
    • synapses between preganglionic and postganglionic neurons
    • junctions between postganglionic and their effector organs

    • ex:
    • CNS-------->ganglion--------->organ

  5. adrenal medulla
    influences the body by releasing epinephrine into the bloodstream

    similar in function to a postganglionic neuron; ex: CNS~~~~~>A. medulla=====>organs
  6. 2 sites where drugs affect sympathetic nervous system
    • synapses between preganclionic and postgonglianic nerons, including the adrenal medulla
    • junctions between postganglionic neurons and their effector organs

    see fig. 13-3 on pg 109
  7. 3 neurotransmitters of the parasympathetic nervous system
    • acetylcholine, epinephrine, norepinephrine
    • any given junction in pns uses ONLY ONE neurotransmitter

    note: dopamine can be put in this group although its role is not consistent
  8. acetylcholine
    neurotransmitter used in most junctions of the pns
  9. acetylcholine is neurotransmitter released by:
    • preganglionic neurons of para.nerv. sx. and symp. nerv. sx.
    • all postganglionic neurons
    • all motor neurons to skeletal muscles
    • most postganglionic neurons of symp. nerv. sx. that go to sweat glands
  10. norepinephrine
    neurotransmitter released by most all postganglionic neurons of symp. nerv. sx.
  11. epinephrine
    major neurotransmitter released by adrenal medulla
  12. 2 receptor types of peripheral nerv. sx.:
    cholinergic and adrenergic recepters
  13. cholinergic receptors respond to what?
    mediate responses to acetylcholine
  14. adrenergic receptors respond to what?
    epinephrine and norepinephrine
  15. what are the 3 receptor subtypes for cholinergic receptors?
    nicotinic N, nicotinic M, muscarinic
  16. what are the 4 major subtypes of adrenergic receptors?
    alpha 1, alpha 2, beta 1, beta 2

    *dopamine is also classified adrenergic but dopamine receptors do NOT respond to epi or norepi- ONLY to dopamine
  17. where is dopamine found primarily?
  18. what does receptor subtypes mean?
    it means that even though there could be receptors that respond to the same transmitter doesn't mean that they will indeed react to that transmitter.

    ex: peripheral receptors that respond to acetylcholine can be found in differnt places but even though they belong to the cholinergic family they are slightly different and require a subtype. pg. 110
  19. muscarinic agonists
    cholinergic receptor subtype
  20. bethanecol is used to treat:
    urinary retention
  21. mechanism of action for bethanicol (urinary retention trx)
    binds reversibly to muscarinic cholinergic receptors causes activation
  22. bethanicol adverse effects
    cardiovascular system hypotension----> smooth muscle relaxation, decrease heart rate

    alimentary system----> diarrhea, abdominal cramps

    urinary tract----->contraction may cause bladder rupture

    exacerbation of asthma-----> bronchoconstriciton
  23. muscarinic distribution are in:
    heart, bladder, lungs
  24. atropine mechanism of action
    blocks muscarinic receptors
  25. atropine pharmacologic effects
    • heart increases rate
    • exocrine glands-decreases secretions
    • smooth muscle bronchial relaxation
  26. atropine therapeutic use:
    • ocular surgery
    • bradycardia- stimulates rate
    • muscarinic agonist poisoning
    • prevention of secretions
  27. atropine adverse effects:
    • xerostomia (dry mouth)
    • blurred vision and photophobia
    • elevation of intraocular pressure
    • urinary retention
    • constipation
    • anhidrosis--->absence of sweat
    • tachycardia
    • asthma
  28. atropine drug interactions:
    avoid comining atropine with other drugs capable of causing muscarinic blockade
  29. atropine preparations/administration:
    • atropine for cholinesterase inhibitor poisoning (insecticides)
    • reversal of bradychardia (IV administration)
    • opthalmology (eye drops to open pupil)
  30. cholinergic effects:
    • increase secretions
    • increase urine output
    • diahrrea
  31. muscarinic antagonists (anticholinergic drugs)
    • ipatropium bromide- decrease asthma secretions
    • antisecretory anticholinergics- Hyoscyamine---> death rattle "lots of mucus secretions"
    • Dicyclomine- GI antidiahrreal
  32. receptor substype Nicotinic N:
    • located in autonomic system
    • stimulation of parasympathetic and sympathetic nerves and release of epi from adrenal medulla
  33. Nicotinic N:
    • located in neuromuscular junction
    • response to activation is contraction of skeletal muscle
  34. Muscarinic receptors: (feed/breed actions)
    • parasympathetic target organs:
    • eye-contract ciliary muscle focuses lens for near vision, contraction of iris
    • heart- decrease heart rate
    • lung- constriction of bronchi
    • bladder- increase bladder pressure and decrease bladder sphincter= voiding/peeing
    • GI tract- salivation, increase gastric secretions, increase intestinal tone, defecation
    • sweat glands- generalized sweating
    • sex organs- erection
    • clood vessels- vasodilation
  35. alpha 1:
    • eye- increase pupil size
    • arterioles- constriction
    • veins-constriction
    • sex organs (male)-ejaculation
    • prostate capsule- contraction
    • bladder- contraction of sphincter (to pee)
  36. beta 1:
    • heart- increased rate, increase force of contraction, increase AV conduction
    • kidney- renin release (blood pressure)
  37. beta 2:
    • arterioles, lung, heart, skeletal muscle- dilation
    • bronchi- dilation
    • uterus- relaxation
    • liver- glycogenolysis
    • skeletal muscle- enahnced contraction, glycogenolysis
  38. dopamine:
    kidney- dilation of kidney vascular
  39. neurotransmission at cholinergic junctions is terminated by:
    breakdown of acetylcholine by acetylcholinesterase
  40. neurotransmission at adrenergic junctions is terminated by:
    reuptake of intact norepi into nerve terminals
  41. following reuptake norepi can be:
    stored in vesicles for reuse or destroyed by monoamine oxidase (MAOI)
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Pharm Review Ch 13: Peripheral Nervous System
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