When a muscle contracts, what happens to the H zones? What is a rigor mortis and why does it occur?

1 Answer
Write your answer here...
Start with a one sentence answer
Then teach the underlying concepts
Don't copy without citing sources


Write a one sentence answer...



Explain in detail...


I want someone to double check my answer

Describe your changes (optional) 200

Dec 12, 2017

Answer of 1st Question:
H-zone is contained by thick filament only. It appears as a lighter band in the middle of the dark A band at the center of a sarcomere.
According to sliding filament model of muscle contraction: When muscles contract then Z-lines come close each other, I-band shortens and #tt(color(orange)"H-zone disappears"#.

Answer of 2nd Question:

The stiffening of body after death is termed as rigor mortis.

ATP is needed to break the link between actin and myosin bridges that are formed as a result of contraction. But the amount of #ATP# in the body falls after death. And the links or cross-bridges can't be broken. Thus these bridges remain firmly bound. Consequently, the body becomes stiff after death and this condition is termed as rigor mortis.

Hope it helps...

Was this helpful? Let the contributor know!