Muscles....

[jon0013]

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does anyone have a way of remembering what A,Z, H, and I lines are? specifically which ones shorten when musles contract? i think H and I shorten but im not sure...thx

 

[jaegwon]

I don't have any brilliant mnemonics or anything for you but this is how it works.


1) I band contains thin filaments only
2) H band contains thick filaments only
3) A band contains all of the thick filaments (including the part that overlaps with the actin - the H band doesn't include these parts)
4) Z line is what the actin filaments are anchored to (these are the boundaries of an individual sarcomere)

Think of the myosin filament as fixed (the A band doesn't shorten) and the actin as pulling in to either side of it. Everything with actin shortens: H zone and the I band...you were right about that.

 

[automaton]

HIZ contracts
A stays the same

 

[jon0013]

HIZ contracts
A stays the same

i dont remmeber Z contracting....does anyone know if its H and I or H,I, and Z that contract

 

[automaton]

i dont remmeber Z contracting....does anyone know if its H and I or H,I, and Z that contract

HIZ contracts
A stays the same.

 

[RayhanS1282]

does anyone have a way of remembering what A,Z, H, and I lines are? specifically which ones shorten when musles contract? i think H and I shorten but im not sure...thx

I use "Say HI to muscle", the H and I contract and get smaller and the Z moves closer and approaches the H and I.