AMAZING thank you, thank you 🥰🥰🥰! the example is so simple and amazing (the muscle reaching to scratch my right ear needs a summation of AP to make a smooth movement rather than twitchy vs. recruitment of many motor units for lifting heavier objects....) I will never forget this example.
Hello Sarah, Maybe my following question(s) could be ultimately reduced to "what do we mean by voluntary", but I hope you find them interesting nonetheless. I understand that muscle cells in skeletal muscles are signaled by neurons in the somatic nervous system. In turn, I understand that this is how we voluntarily generate the force necessary to lift a weight, or in general, to generate force. Given that the process of generating force (e.g., to pick something up) is voluntary: • Are there any contractions in these muscles that could be not-voluntary? • Is the process of force generation in muscles then 'fundamentally' independent from external stimuli? • Is there an upper bound on the amount of force generation absent external stimuli that is not-equal to the upper bound in the presence of external stimuli?
I agree the question of "what is voluntary" is fraught; but we could simplify by saying "would be identified by the person as intended" which is still problematic but maybe useful. In that case (or really under any acceptable definition of "voluntary") there are certainly potentially non-voluntary movements of skeletal muscles, such as in seizures, removing your hand from a hot stove, etc. The mechanism is the same though (in terms of what makes the muscle contract, and certainly summation, recruitment. etc.) I don't see a particular relationship between dependence on external stimuli and voluntary-ness, since you could have either one without the other, plus you have to decide what counts as "external stimuli," another can of worms. The upper bound on the amount of force is set by the number and size of muscle fibers in the muscle. Could more force be applied non-voluntarily than voluntarily, such as in cases when people e.g. lift cars off their children and so on? It could be, if there is a resting low-level inhibition of motor neurons which is lifted in emergency situations, allowing a greater action potential frequency than the person could ever generate when they "decided" to. This would be hard to study but is physiologically possible, and of course could (at least in part) explain the apparently extraordinary power of individuals in such stories.
Thank you so much for creating this video... I have exam 3 for my Physio class coming up and it will include all this wonderful stuff that is so hard to grasp. God Bless you for being a wonderful teacher.
Can you please give the example of twitch, summation and tetanus from the real life? If i am curling a dumbell for 10 repetitions ... Is that summation or tetanus ... And Is plank a tetanus ?
All real life movements, such as the weight lifting movements you describe, involve summation and tetanus. You wouldn't see a twitch in real life, except for pathological situations. Even in an isometric exercise like a plank where there's no movement, the muscle is contracting smoothly (tetanus) to allow you to maintain your awesome plank.
Dang she explained that excellently. Well done
This really clarified what my textbook is saying in a much more digestible way! Thank you. Difficult concept but you explained it well.
AMAZING thank you, thank you 🥰🥰🥰! the example is so simple and amazing (the muscle reaching to scratch my right ear needs a summation of AP to make a smooth movement rather than twitchy vs. recruitment of many motor units for lifting heavier objects....) I will never forget this example.
You're a truly great teacher ma'am. I feel lucky to have found your channel.
THANK YOU! WHY can't any textbooks just say that???
Thank you so very much. Wish you were our professor... You are great!
Great explanation
i was struggling with these concept and finally i found you thankyou ❤
This was awesome thanks
WOW... That was an excellent explanation...
awesome! thank you!
Thanks a lot for the information and the great work🙏🏼❤️
Love you for clearing my concepts.
thank you so much, you made my day , keep theggood work.
excelent!!! thank you so much
excellent*
Thank you for clearing that up!
Hello Sarah,
Maybe my following question(s) could be ultimately reduced to "what do we mean by voluntary", but I hope you find them interesting nonetheless.
I understand that muscle cells in skeletal muscles are signaled by neurons in the somatic nervous system.
In turn, I understand that this is how we voluntarily generate the force necessary to lift a weight, or in general, to generate force.
Given that the process of generating force (e.g., to pick something up) is voluntary:
• Are there any contractions in these muscles that could be not-voluntary?
• Is the process of force generation in muscles then 'fundamentally' independent from external stimuli?
• Is there an upper bound on the amount of force generation absent external stimuli
that is not-equal to the upper bound in the presence of external stimuli?
I agree the question of "what is voluntary" is fraught; but we could simplify by saying "would be identified by the person as intended" which is still problematic but maybe useful. In that case (or really under any acceptable definition of "voluntary") there are certainly potentially non-voluntary movements of skeletal muscles, such as in seizures, removing your hand from a hot stove, etc. The mechanism is the same though (in terms of what makes the muscle contract, and certainly summation, recruitment. etc.) I don't see a particular relationship between dependence on external stimuli and voluntary-ness, since you could have either one without the other, plus you have to decide what counts as "external stimuli," another can of worms. The upper bound on the amount of force is set by the number and size of muscle fibers in the muscle. Could more force be applied non-voluntarily than voluntarily, such as in cases when people e.g. lift cars off their children and so on? It could be, if there is a resting low-level inhibition of motor neurons which is lifted in emergency situations, allowing a greater action potential frequency than the person could ever generate when they "decided" to. This would be hard to study but is physiologically possible, and of course could (at least in part) explain the apparently extraordinary power of individuals in such stories.
Thank you so much! amazing explanation!
Thank you so much for creating this video... I have exam 3 for my Physio class coming up and it will include all this wonderful stuff that is so hard to grasp. God Bless you for being a wonderful teacher.
Good luck on your exam, Ana!
Thank you...I am sure I will do well on this part thanks to you..@@sleupen
Great great video!!! Helps a lot with my exams :)
you are great , thank you .
Thanks for helping me prepare for my exam!
Amazing 👍 understand it well
Great explanation! Thank you a lot!
thank you, thank you and still thank you!!
This is so helpful
Thank u so much for explaining 😊
Thank you. It was really helpful.
Thank you !
nice
Could you give a real life example for spatial vs wave summation please?
It's all through the video, especially the part where I lift the weight! "Spatial summation" (in this context) is what we now call recruitment.
@@sleupen Thank you!
What is the name of the textbook which you take the figures from?
Most of them are from Silverthorn's Human Physiology book, the one I have access to :-)
@@sleupen Thank you
Can you please give the example of twitch, summation and tetanus from the real life? If i am curling a dumbell for 10 repetitions ... Is that summation or tetanus ... And Is plank a tetanus ?
All real life movements, such as the weight lifting movements you describe, involve summation and tetanus. You wouldn't see a twitch in real life, except for pathological situations. Even in an isometric exercise like a plank where there's no movement, the muscle is contracting smoothly (tetanus) to allow you to maintain your awesome plank.
Thank you!