ma'am one thing has struck my brain , looking at the arrangement of thick and thin filaments , it seems like during muscle contraction all the forces of pull exerted by myosin heads on actin filaments get cancelled out . Consider 3 adjacent sarcomere units. Now imagine , the myosin heads of central sarcomere are pulling actin filaments close together . But same is happening on the two adjacent sarcomeres on its each side as well. Now , as the actin filaments of adjacent sarcomeres are attached to the same Z disk where actin filaments of central sarcomere are also attached . Meaning , the force of pull of the myosin heads on Z disk and actin filament will cancel out . Then how is it possible for sarcomere to shorten at all. In the figures that we get in books as well as in internet , they just seem to focus on one sarcomere unit but when I consider what's happening on adjacent sarcomeres it seems like the forces get cancelled out. Please ma'am do help
Stretching means increase in the length of muscle which occurs when muscle relaxes from its basal tone... Or other way is when tendons are pulled from its ends ...this also stretches the sarcomere..since tendons are in parallel to sarcomere
No contraction produces active tension...this is how if length affects active tension, if length is too much, I.e. of muscle is too much strength, then hardly actin-myosin interact, thus may not contract and thus no active tension (however passive tension in muscle will increase)
@@PhysiologyOpen means active tension increases while contraction although sarcomere approximates each other that is shortening of muscle fiber during contraction increases active tension in muscle, am I right
@@PhysiologyOpen one more question active tension can only be produced when there is some external agent that is some passive tension source or it can be produced without passive tension too and also why golgi tendon organs are effective only against active tension but not against passive tension,
ma'am one thing has struck my brain , looking at the arrangement of thick and thin filaments , it seems like during muscle contraction all the forces of pull exerted by myosin heads on actin filaments get cancelled out .
Consider 3 adjacent sarcomere units. Now imagine , the myosin heads of central sarcomere are pulling actin filaments close together . But same is happening on the two adjacent sarcomeres on its each side as well. Now , as the actin filaments of adjacent sarcomeres are attached to the same Z disk where actin filaments of central sarcomere are also attached . Meaning , the force of pull of the myosin heads on Z disk and actin filament will cancel out . Then how is it possible for sarcomere to shorten at all.
In the figures that we get in books as well as in internet , they just seem to focus on one sarcomere unit but when I consider what's happening on adjacent sarcomeres it seems like the forces get cancelled out.
Please ma'am do help
Ends are non-contractile- they are tendons...all the pull ultimately pulls tendons..
Thanku mam its very useful💜🖤
My pleasure
mam thank u.this is useful for me
Really glad
Thanks for good video !!
Thanks
Thnkuuuuuu so much ma'am 🥺❤️
Most welcome 😊
Mam how is it different between stretching and contracting a muscle at sarcomere level
Stretching will stretch the sarcomere...contraction will shorten the sarcomere...same as told in the video
@@PhysiologyOpen mam when cross bridge is formed myosin pulls the actin filament and length of sarcomere decrease how does stretching occur mam
Stretching means increase in the length of muscle which occurs when muscle relaxes from its basal tone...
Or other way is when tendons are pulled from its ends ...this also stretches the sarcomere..since tendons are in parallel to sarcomere
@@PhysiologyOpen tq mam 🙏
Thankyou
You’re welcome 😊
So it means as the contraction proceeds tension decreases
No contraction produces active tension...this is how if length affects active tension, if length is too much, I.e. of muscle is too much strength, then hardly actin-myosin interact, thus may not contract and thus no active tension (however passive tension in muscle will increase)
@@PhysiologyOpen means active tension increases while contraction although sarcomere approximates each other that is shortening of muscle fiber during contraction increases active tension in muscle, am I right
Yes
@@PhysiologyOpen thanku so much
@@PhysiologyOpen one more question active tension can only be produced when there is some external agent that is some passive tension source or it can be produced without passive tension too and also why golgi tendon organs are effective only against active tension but not against passive tension,
Can we have notes of this ?
Notes on skeletal muscle physiology soon releasing