Z lines change? Edit: Nevermind--Z lines change

[SaintJude]

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Nevermind z-lines change. Princeton was wrong.

TPRH discrete no.110

during skeletal muscle contraction, which band can be seen to to contract under microscope

A. the i band and h zone
D. the z line

Princeton: Z lines are ends of sarcomere. the length of these do not change during contraction

Kaplan: Z-lines, I-band and H-zone--all of the get smaller or closer together during contraction because they are defined relative to one another

Anyone have EK or BR to finalize who is right?

 

[Dasypus]

Nevermind z-lines change. Princeton was wrong.

TPRH discrete no.110

during skeletal muscle contraction, which band can be seen to to contract under microscope

A. the i band and h zone
D. the z line

Princeton: Z lines are ends of sarcomere. the length of these do not change during contraction

Kaplan: Z-lines, I-band and H-zone--all of the get smaller or closer together during contraction because they are defined relative to one another

Anyone have EK or BR to finalize who is right?

I bolded the important point. Z-lines do not get shorter, but they do get closer together. PR and Kaplan are consistent with each other.

 

[Morsetlis]

The length of the A-band stays the same. Everybody else move closer to the M-line.

Note that the M-line and the Z-disc do not change in their (minuscule) length, but you should think of them as points and not actual distances.

 

[icewave667]

From EK: Z moves closer during muscle contraction, and Z moves apart during muscle relaxation (however this is not shortening/lengthening)

A is the same for everything

H and I shortens for contraction and lengthens for relaxation