UMMC Pharm test2 PNS

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UMMC Pharm test2 PNS
2012-10-07 23:06:08
UMMC Pharm test2 PNS

UMMC Pharm test2 PNS
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  1. What chemical is secreted by the liver and binds to Ach in the plasma?
  2. How many Ach molecules are required to open the nicotinic cholinergic receptor?
  3. What is the rate limiting step and enzyme in the production of epinephrine?
    • Tyrosine to DOPA
    • Enzyme is tyrosine hydroxylase
  4. List the epinephrine production pathway starting with Tyrosine along with enzymes
    • Tyrosine  DOPA : Tyrosine hydroxylase
    • DOPA  Dopamine : DOPA decarboxylase
    • Dopamine  Norepinephrine : Dopamine – beta – hydroxylase
    • Norepinephrine  Epinephrine : PMNT (Phyenylethanolamine-N-methyltransferase)
  5. What is the result of Alpha-1 Adrenoceptor signaling?
    • IP3 increases calcium and DAG increases protein kinase C
    • Contracts smooth muscle
  6. What is the result of Alpha-2 Adrenoceptor signaling?
    • Decreases calcium entry into cells
    • Increases potassium leaking
    • Inhibits camp production
  7. What is the result of Beta adrenergic signaling?
    Increases camp
  8. What type receptor is on all autonomic effectors?
  9. What are metabotropic receptors?
  10. What is a syncytium?
    Cells connected by gap junctions
  11. What is known as the cranio-sacral branch of the ANS?
    The PNS
  12. Which has longer preganglionic nerves, the PNS or SNS?
  13. What is the ratio of postganglionic to preganglionic nerves for the PNS?
    1 to 1
  14. Is the PNS or the SNS more selective at activating a single organ?
    • The PNS
    • Think of the SNS activating many organs at once during a fight or flight response, whereas the PNS has time to selectively activate only the organs that need to do work at that time
  15. What is the ratio of postganglionic to preganglionic nerves for the SNS?
    20-200 to 1
  16. Where is the myenteric (Auerbach’s) plexus located and what is its function?
    Between the longitudinal and circular smooth muscle layers. It regulates motility
  17. Where is the submucous (Meissner’s) plexus? And what is its function?
    Between the circular smooth muscle and the mucosa. It regulates mucosal absorption and secretion
  18. What nervous inputs do the GI and smooth muscle and mucosa receive from the PNS and SNS?
    PNS and SNS afferent as well as Efferent Preganglionic Parasympathetic and Efferent Postganglionic sympathetic
  19. What is the primary neurotransmitter in neuromuscular junctions?
  20. What type receptors do skeletal muscles express?
    • Nicotinic cholinergic receptors
    • (ligand-gated ion channels)
  21. Does a muscle fiber exhibit all or none response or is it a graded response?
    An individual muscle fiber exhibits an all or none response
  22. What are the four NT that mediate chemical transmission at most peripheral synapses?
    ACh, DA, NE, and Epi
  23. What are the exceptions to the rule that Sympathetic postganglionic nerves release NE?
    • Adrenal medulla – there are no postganglionic nerves, only preganglionic (release 80% epi, 20% NE)
    • Renal, cerebral, and mesenteric blood vessels – dopamine (DA)
    • Eccrine sweat glands – ACh
  24. What is the rate limiting step in ACh synthesis?
    The transport of choline into the cholinergic nerve terminal via the choline transporter using the energy of the Na+ gradient
  25. Where is ACh synthesized? What enzyme is used?
    • In the cytosol from choline and acetyl CoA
    • Choline acetyltransferase (ChAT)
  26. What type of transport gets ACh into synaptic vesicles?
    • A combination of Secondary and Primary active transport
    • The cell concentrates H+ in the vesicle using ATP, the H+ (Primary active transport)
    • This gradient is then used to exchange H+ for ACh+ (Secondary active transport)
  27. What signal initiates synaptic vesicle release?
    Voltage gated Ca+2 channels depolarize allowing Ca+2 into the cell to trigger fusion of synaptic vesicles with the nerve terminal membrane
  28. What is the difference between nicotinic and muscarinic cholinergic receptors?
    • Nicotinic cholinergic receptors are ligand-gated ion channels
    • Muscarinic cholinergic receptors are G-protein coupled receptors
  29. Where are Nicotinic receptors found?
    • All cells of autonomic ganglia
    • Adrenal medulla
    • Skeletal muscle
  30. Where are muscarinic receptors found?
    • Heart
    • Smooth muscle
    • Glands
  31. Where is the enzyme AChE found?
    On the postsynaptic membrane
  32. What subunits make up Neural nicotinic receptors?
    2alpha and 3 beta subunits
  33. What receptor subunits are in post-ganglionic autonomic neurons (nicotinic)?
    • Two alpha3 and three beta4 (alpha3beta4 nicotinic receptors)
    • Some alpha7
  34. What receptor subunits are in CNS neurons?
    • Alpha4beta2
    • Some alpha7
  35. What receptor subunits are in fetal or denervated skeletal muscle?
  36. What receptor subunits are in normal adult muscle?
  37. Do autonomic nerve terminals exhibit a low or high safety factor of transmission?
  38. What does the term “safety factor” mean with regard to nerve terminals?
    • How much NT is released compared with how much was required to elicit a response
    • If the safety factor is low, there is not enough NT released to elicit a response
    • If the safety factor is high there is more than enough NT to elicit a response
  39. Do skeletal muscle receptors exhibit a high or a low safety factor of transmission?
  40. What occurs with stimulation of the M1, M3, or M5 receptors?
    • Gqa activation of the Phospholipase C pathway (Ip3 and DAG)
    • Stimulation of smooth muscles, exocrine glands, and autonomic neurons
  41. What occurs with stimulation of the M2 or M4 receptors?
    • Gia inhibition of adenylyl cyclase or activation of K+ channels and inhibition of Ca2+ channels for hyperpolarization
    • Inhibits heart, autonomic nerve terminals, and autonomic neurons
  42. What type receptors are adrenergic and dopaminergic receptors?
  43. What stimulates Beta2 receptors?
    Epi, but not NorEpi
  44. What stimulates Beta1 receptors?
    Epi and NorEpi
  45. What receptors stimulate aqueuous humor production in the eye and renin secretion by the Juxtaglomerular cells of the kidney?
    Beta 1 adrenergic
  46. What receptor mediates sympathetic lipolysis and relaxation of GI smooth muscle?
    Beta 3 adrenoceptors
  47. Which dopaminergic receptors are exititory and cause relaxation and vasodilatation?
    D 1, D 3, and D 5
  48. Which dopaminergic receptors are inhibitory and cause hyperpolarization?
    D 2 and D 4
  49. What is the result if treatment of adrenergic agonists or antagonists is abruptly ended?
    Because of the receptor up or down regulation that takes place, the patient is at risk for adverse cardiovascular responses
  50. What is the precursor to NO and what enzyme is used?
    L-arginine via nitric oxide synthase
  51. What is the function of NO?
    Activates guanylyl cyclase resulting in smooth muscle relaxation
  52. What enzyme deactivates NO?
    Superoxide dismutase
  53. What receptors are found on the pupillary sphincter muscle to constrict the pupil in response to parasympathetic innervation?
    M3 – which is also the receptor found in the ciliary body (which focuses the lens)
  54. What receptors are found on the radial dilator muscle that increase pupil diameter in response to sympathetic stimulation?
    Alpha 1
  55. How does the sympathetic system cause far vision?
    Signals are sent to presynaptic alpha 2 receptors on parasympathetic nerve terminals which reduce parasympathetic tone resulting in relaxing of the ciliary muscle and flattening of the lens
  56. What do muscarinic receptor agonists and AChE inhibitors accomplish for the eye and what are the side effects?
    • Contract ciliary muscle, which opens the canal of Schlemm and reduces intraocular pressure
    • Side effect is impaired far vision and miosis (pupillary constriction)
  57. What has higher affinity for Epi and Norepi, Beta or alpha?
  58. What do beta1 adrenoceptor antagonists and alpha2 adrenoceptor agonists do to intraocular pressure in glaucoma patients?
    They inhibit aqueous humor formation and lower intraocular pressure
  59. What governs tear production in lacrimal glands?
    • M3 from parasympathetic produce tears
    • The sympathetic system can stimulate blood vessel contraction via alpha 1 receptors on vascular SM which reduces tear production
    • Circulating Epi or NE can also effect the alpha1 receptors resulting in protein-rich tears
    • Circulating low levels of Epi stimulate Beta 2 receptors resulting in watery tear production
  60. What is a telltale sign of overdose with either a muscarinic agonist or AChE inhibitor?
    Profuse, watery tears
  61. What is the result of parasympathetic stimulation of cardiac muscle and what receptor is responsible?
    • M2 receptors
    • The result is decreased amplitude and upstroke velocity of action potentials, and membrane hyperpolarization. This causes decreased HR (chronotropy), decreased conduction velocity (dromotropy), and contractile force (inotropy)
  62. What receptors are responsible for stimulating cardiac muscle with circulating Epi and sympathetically stimulated NE?
    • Beta 1
    • Causes increased cardiac output
  63. Does the vasculature receive parasympathetic input?
    • No, sympathetic only
    • However, there are M3 receptors that cause production of NO and vasodilation if exogenous M3 is added to the circulation.
  64. Why does Epinephrine at low concentrations cause vasodilation?
    Arteries express both alpha1 and beta2 receptors. The beta2 receptors have a higher affinity than alpha1 receptors, so at low concentrations the beta2 response is dominate.
  65. What receptors on bronchiole smooth muscle cause contraction?
    • M3
    • Also M3 receptors on mucosal epithelial cells stimulate mucous secretion
  66. How does the sympathetic system effect the respiratory smooth muscle and epithelium?
    • Alpha2 receptors on the preganglionic parasympathetic nerves decrease parasympathetic tone
    • Adrenal Epi causes bronchodilation via Beta2 receptors in smooth muscle
  67. What effect does the parasympathetic system have on the gut?
    Alpha3Beta4 Nn receptors generate fast EPSPs and action potentials which contract muscles of the gut wall and relax the sphincters
  68. What three effect does the sympathetic system have on the gut?
    • Postganglionic sympathetic nerves innervate Alpha2 receptors on preganglionic parasympathetic neurons to inhibit them, thus relaxing the gut
    • GI sphincters are also innervated with alpha1 receptors to be contracted
    • Circulating epi can cause relaxation via beta2 and beta 3
  69. ACh released from submucous secretomotor neurons has an effect on histamine, gastrin, acid, and Somatostatin secretion. What is its effects on each and by what receptors?
    • Histamine (M1) stimulate
    • Gastrin (M3) stimulate
    • Acid (M3) stimulate
    • Somatostatin (M2) inhibit
  70. What effects on submucous secretomotor neurons do parasympathetic and sympathetic stimulating have?
    • Sympathetic inhibit via alpha 2
    • Parasympathetic stimulate via alpha3beta4 Nn receptors
  71. What effect does the parasympathetic system have on the islet of Langerhans cells?
    Ach stimulates M3 receptors on the Beta cells to increase insulin production
  72. What effect does the sympathetic system have on the islet of Langerhans cells?
    • NE from sympathetic nerves or circulating Epi stimulate alpha1 receptors on alpha cells to produce glucagon and they stimulate alpha2 receptors on beta cells to inhibit insulin production
    • Sympathetic nerves also vasoconstrict vessels which redistributes blood from beta to alpha cells and they inhibit parasympathetic nerves
  73. What receptor is responsible for acute pancreatitis?
    • M3 receptor
    • This is hyperstimulized when gallstones occlude the common bile duct and pancreatic flow is slowed. Reflex parasympathetic responses attempt to increase pancreatic flow, causing acute pancreatitis
  74. What receptor stimulates salivary secretion?
    M3 from the parasympathetic system
  75. Does the sympathetic system directly or indirectly inhibit salivary secretion?
    Indirect via alpha 2 on parasympathetic and by vasoconstriction
  76. What is the net effect on salivary glands of sympathetic stimulation?
    Decreased secretion volume and increased viscosity
  77. Does M3 receptor stimulation of salivary glands cause saliva production or does it inhibit?
    Causes production of saliva
  78. What does parasympathetic stimulation do to the detrusor muscle and trigone?
    M3 receptors constrict the detrusor muscle and M2 receptors inhibit trigone contraction
  79. What does sympathetic stimulation do to the detrusor and trigone?
    • Trigone contracts via alpha1
    • Detrusor relaxes due to alpha 2 stimulation to preganglionic parasympathetic
    • Circulating EPI stimulates beta2 receptors to relax detrusor muscle
  80. How would you treat an overactive bladder?
    M3 receptor antagonist
  81. When a pregnancy goes to term what causes the uterine contraction of labor?
    A spike in maternal estrogen and oxytocin combined with a release of prostaglandins from fetal membranes
  82. Why is exposure to NE, Epi, alpha 1 agonists, or drugs that release Epi or NE contraindicated in pregnancy?
    • During pregnancy most autonomic innervation, especially SNS nerve terminals disappear
    • This loss of terminals causes alpha 1 receptors to up-regulate
    • Stimulation of up-regulated receptors can result in spontaneous labor
  83. What drugs are used to arrest and prevent premature labor?
    Beta 2 agonists
  84. What drugs are used postpartum to restore uterine tone and to stop postpartum bleeding?
    Alpha 1 agonists
  85. How is erectile disfunction usually treated?
    Inhibitors of cGMP phosphodiesterase
  86. In a diabetic what effect would exogenous Beta 2 or alpha 1 agonists have on blood sugar?
    They would raise blood sugar
  87. What sympathetic receptors stimulate lipolysis?
    Beta 3 adrenoceptors
  88. How are eccrine sweat glands stimulated?
    • M3 receptors from the sympathetic system (cholinergic)
    • Critical for evaporative cooling in elevated temperatures
  89. How are apocrine sweat glands stimulated?
    • Noradrenergic sympathetics via alpha 1 receptors
    • This is the type sweating that occurs during emotional stress
  90. What causes Piloerection?
    Noradrenergic stimulation via alpha 1 receptors