Sarcomere Structure And Function Flashcards
What are the four regions of a sarcomere?
- H zone
- A band
- I band
- Z disc
What is the acronym, from inside to outside, for the regions in the sarcomere?
HAIZ
From inside to outside, what are the types of regions of the sarcomere?
Zone band band disc
What is the A band?
The length of the myosin
What is the I band?
Actin but no myosin
What is the H zone?
Myosin but no actin
What is the Z disc?
The walls, neither actin nor myosin
What regions of the sarcomere do not change the length?
A band and Z disc
What regions of the sarcomere shorten when the muscle contracts?
H zone and I band
What happens to the Z lines during concentric contraction?
They get closer together
What does tropomyosin do when the muscle is not contracted?
Covers the myosin-binding site
What activates troponin?
Calcium
What does troponin do when calcium binds to it?
Pulls tropomyosin out of the way of myosin-binding sites