autonomic regulation of cell AP Flashcards
how does ANS mediate cardiac contractions
through hormones released in vicinity
what does symp and para do to CO
symp - incr.
para - decreae
what part of heart can para and symp affect?
symp - node and myocytes
para -nodes only
what are used by symp and para to signal
para - Ach
symp - NA (noradrenaline)
speed at which symp and para work
para - fast on and off
symp - slow on and off
what receptors are activated by symp and para
para - M2
symp - a and B receptors
what are M2 channels directly couples to?
ion channels - fast
what do a and B receptors work by
enzyme cascade - cAMP and PKA
what does symp do to AP
increase rate of repolarization
what does para do to AP
hyperpolarizes cell, which leads to slower contractions
what are 4 effector pathways of para
- GIRK activation - K out - hyperpolarize cell
- inhibits cAMP
- less cAMP means less Cav - less upstroke
- less cAMP means less funny current activation - longer pacemaker potential
what are 3 effectors of symp.
- M2 receptor means more cAMP
- more cAMP means increased funny channel - smaller pacemaker potential
- more cAMP means more Cav activity
where does most heart rate control come from
vagal tone (60-70%)
what would happen without vagus
heart rate up to 100-110
what are 2 ways to increase CO
- pump faster
2. pump harder
