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theprimegrinder wrote: ↑February 16th, 2020, 11:36 am Look at this link:
https://ib.bioninja.com.au/higher-level ... ction.html

It also helps to watch some videos. Khan Academy has some good ones about muscle contraction

I would say you have to learn it very in depth

Thank you, and also could someone please share a diagram of the muscles of the trunk? I tried looking for them but I couldn't really find a clear one, so if anyone has a good diagram please share it with me.

Thx,
donuts

I probably sound dumb but what's the difference between neuromuscular junction and muscle contraction? By that I mean isn't nueromuscular junction the beginning of the contraction then the binding of myosin and actin occurs, isnt that basically the whole muscle contraction? Sorry if I sound slow...

donutsandcupcakes wrote: ↑February 16th, 2020, 12:36 pm I probably sound dumb but what's the difference between neuromuscular junction and muscle contraction? By that I mean isn't nueromuscular junction the beginning of the contraction then the binding of myosin and actin occurs, isnt that basically the whole muscle contraction? Sorry if I sound slow...

I'm not sure myself, but it probably depends on how it's defined, it makes sense that it's all part of muscle contraction. I think one could also say that what happens at the neuromuscular junction initiates contraction and the contraction itself is the sliding filament stuff with actin and myosin.

donutsandcupcakes wrote: ↑February 16th, 2020, 12:36 pm I probably sound dumb but what's the difference between neuromuscular junction and muscle contraction? By that I mean isn't nueromuscular junction the beginning of the contraction then the binding of myosin and actin occurs, isnt that basically the whole muscle contraction? Sorry if I sound slow...

The neuromuscular junction has acetylcholine (ACh) receptors. ACh stimulates contraction, but it’s not part of the process itself. I think that’s the difference. The NMJ is also a structure, not a step in contraction.

Also, the binding of myosin to actin is a whole process which needs to be studied. It is basically what contraction is, but it has some steps to it.

donutsandcupcakes wrote: ↑February 16th, 2020, 12:36 pm I probably sound dumb but what's the difference between neuromuscular junction and muscle contraction? By that I mean isn't nueromuscular junction the beginning of the contraction then the binding of myosin and actin occurs, isnt that basically the whole muscle contraction? Sorry if I sound slow...

contraction does not start at neuromuscular junction. excitation starts at NMJ.
a muscle contraction has 2 components - excitation and contraction. (excitation-contraction coupling)
nerve impulse reaches nerve ending -> acetylcholine released -> leads to end plate potential -> action potential -> AP spreads through t-tubules and Sarcoplasmic reticulum -> calcium release -> calcium binds with troponin -> tropomyosin moves exposing the myosin binding sites on actin. upto this is excitation, and the steps from here on are contraction.
hope this make it clear?

Has anyone gotten questions about bone development? And I was trying to make a cheat sheet and I couldn't find a good image for the muscles of the trunk so if anyone found a good pic then let me know, pls

sciencenerd123 wrote: ↑February 19th, 2020, 3:07 pm Has anyone gotten questions about bone development? And I was trying to make a cheat sheet and I couldn't find a good image for the muscles of the trunk so if anyone found a good pic then let me know, pls

https://slideplayer.com/slide/8079871/
has some great pictures of the trunk muscles.

If yellow bone marrow can convert to red bone marrow, can red bone marrow convert back to yellow bone marrow? If not, why not? And how does this mechanism work anyway?

WangwithaTang wrote: ↑February 19th, 2020, 10:54 pm If yellow bone marrow can convert to red bone marrow, can red bone marrow convert back to yellow bone marrow? If not, why not? And how does this mechanism work anyway?

At birth, all bone marrow is hematopoietic. This is due to the body's need to produce blood cells at an early age. The maintenance of this hematopoietic tissue requires the support of hematopoietic microenvironment cells—fibroblasts, reticular adventitial cells, and macrophages—specialized mesenchymal cells in the bone marrow cavity.

These microenvironment cells are generally thought of in a three-step pathway:
1.) Support hematopoiesis; contain no adipose tissue (red bone marrow).
2.) Cannot support steady hematopoiesis; contain accumulated adipose tissue. When the body requires more blood cells to be produced—whether due to blood loss, fever, etc.—these cells literally just lose their fat, which allows them to support hematopoiesis again. This effectively reverts them back to the first stage. When the need for increased hematopoiesis declines, these cells continue "maturing."
3.) Cannot support hematopoiesis altogether; primarily contain adipose tissue (yellow bone marrow).

What's the difference between Paralytic polio and spinal polio. In one website, I read spinal polio is a type of paralytic polio, and in other, i read that they aren't connected so I'm confused someone pls help