Autonomic control of CVS Flashcards

1
Q

What parts of the ANS (PS S orginate where from the vertebral coloum)?

whats the 3rd divisionof the nervous system?

A

S = lumbar and thoracic

P = medulla and sacral

-enteric ; network of neurones surrounding the GI tract

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2
Q
A
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3
Q

describe the pathway od nerves from the brain -sympthatic

A

Cardiac acceltaroy centre in the medullla -> spinal cord -> T1-4 -> paravertebral ganglia

  • SAN and AVN and mycocardial muscle
  • beta 1 receptors ADENYL cAMP PK VGcaliuum channels so +ve inontropic effect c more calcium enters causing more calcium released from SERCA bind to tropinin… more forceful contraction
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4
Q

parasymth heart

A

preganglion trunk 10th vagus nerve synapses with post ganglions on epicardial surface of SAN AVN cells causing decrease inAVN excitiabiliy and -ionitropic effect because M2 which is ADENYLINHIBITOR

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5
Q

what happens to an dennerved heart

A

beats faster because under normal conditons heart under vagal influence

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6
Q

describe ANS in terms of the pacemaker graph

-sym

para

A
  • symp = the pacemarker potential is increased slope because b1 stimulation ADE…. + chrontropic effect and more vgcc phosphorylated durign platuae phase
  • para ; pacemaker potential slope decreased because M2 causes inghibior AD less can less contraction
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7
Q

how does noradrenaline cause force of contraction

A

b1 ADE vggc

  • ca2+ more released d phosphorylation during the plataue phase
  • also more ca2+ reputake into SR
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8
Q

ANS vasculature effect

A
  • a 1 c PLC IP3 DAG ^ ca2+ and DAG inhibits MLCP so contraction can continue
  • b2 s ADEN cAMP PK K+ channels which less likely action potential due to hyperpolarisation + inhibits MLCK so no contraction
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9
Q

adrenogenic affintiy

A

greater affinity for b2 = so at first vasodilation

but later due tohigh adrenaline you can get it binding to a 1 so you get vasoconstriction

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10
Q

allergic reaction

why adrenaline

A

vasodilation ^ permeability and ^ CO = ^HR

vasoconstriction to maintain systolic BP

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11
Q

role of metabolites

A

H+ pCO2 lactate acetate suggest low 02 levels and activate b2 and cause vasodilation because the blood wants take as much o2 as possible

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12
Q

describe the overall control of CVS

A

baroreceptors in aortic arch detect changes in pressure due to strecthing (vbp = more strecthing) this send signals to the brain CAC of the medulla sends signal sympatheitc trunch to heart AVN -ve chronotropic SAN -ive chronotropic myocardial muscle -ionotrpic AND bv a1 casuing vasocosnstriction

atrial recpetors in carotid sinus which detect the metabolites and they send changes in chemicals to the brain CAC of medulla activates the PS via m2 receptors c heart to derease AVN excitablity and decrease contraction rate -ve chronotorpic AND bv b2 receptors causing vasodilation

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13
Q

3 types of drugs

A

synpathomimetics ( a b agonists cause vasoconstricion and ^ HR so give to cardiac arrest / cardiogenic shock - b1 DOBUTAMINE /adrenaline anapkysis /b2agnosit give for asthma

cholingeric - ( musacarnic. agonists) contraction of sphincter muscles eye - treatment for gluacama PILOCARPINE // (muscarnainc antagnoist) \ATROPINE TROPICAMIDE dilates upuil and increases hr andbrchoncial dilation

adrenoreceptor antagonist (b2/b1 nonselctive antagonist) used for asthma c vasoconstricion = brconhospasm due to b2 but b1 has an effect where slows heart rate so be careful // beta 2 slective for astham for brchonconstriction

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