physio for all - rsvr

[ArchivalUser]

Q--addition of NE to a solution bathing an isolated cardiac papillary muscle leads to an increase in the amt of work done by the muscle at a given load, without changing the muscles initial length. The increase in the work done by the msucle at its new steady state level is the result of an increase in

a--overlap of actin and myosin at the inital length
b--sarcoplasmic Ca conc while th eload is lifted

please give an explaination, thanks

[ArchivalUser]

b.
NE inc cardiac contraclity via beta 1 receptors which use cAMP as sec messenger, inc cAMP facilitates entry of ca thru ca channels present in memb of cardiac muscle cels,this inturn leads to inc ca entry into sarcoplasmic reticulum via ca- H antiporter resulting in inc conc of ca in sarcoplasmic r which inturn participates in muscle contraction.
correct me if i m wrong

[ArchivalUser]

its BBBB for sure....epinephrine stimulates the beta 1 receptors and the Gs protein....inc cAMP in herat muscle leads ti inc contractility by making more Ca available....i hoipe im right

[ArchivalUser]

bb