Autonomic control of CVS Flashcards
What parts of the ANS (PS S orginate where from the vertebral coloum)?
whats the 3rd divisionof the nervous system?
S = lumbar and thoracic
P = medulla and sacral
-enteric ; network of neurones surrounding the GI tract
describe the pathway od nerves from the brain -sympthatic
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
parasymth heart
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
what happens to an dennerved heart
beats faster because under normal conditons heart under vagal influence
describe ANS in terms of the pacemaker graph
-sym
para
- 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
how does noradrenaline cause force of contraction
b1 ADE vggc
- ca2+ more released d phosphorylation during the plataue phase
- also more ca2+ reputake into SR
ANS vasculature effect
- 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
adrenogenic affintiy
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
allergic reaction
why adrenaline
vasodilation ^ permeability and ^ CO = ^HR
vasoconstriction to maintain systolic BP
role of metabolites
H+ pCO2 lactate acetate suggest low 02 levels and activate b2 and cause vasodilation because the blood wants take as much o2 as possible
describe the overall control of CVS
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
3 types of drugs
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