Muscle Flashcards
1
Q
sarcomere
A
- composed of overlapping filaments of actin and myosin as well as structural and binding proteins (eg, titin, α-actinin).
- single sarcomere is defined as the distance between two Z lines.
- Thin (actin) filaments are bound to structural proteins at the Z line.
- The unbound ends of the actin filaments project into the middle of the sarcomere, where they interact with thick (myosin) filaments during muscle contraction.
- Myosin and actin filaments overlap at the segment of the sarcomere between the H and I bands.
2
Q
A band
A
- myosin filaments in the sarcomere
- In this region, there are myosin filaments overlapped with actin filaments as well as non-overlapped myosin filaments.
- always remains the same length during muscle contraction.
3
Q
M line
A
lies at the center of the A band and is where myosin filaments anchor to structural elements in the center of the sarcomere.
4
Q
I band and H band
A
- I band is the region of the sarcomere in which actin does not overlap with myosin
- H band is the region in which myosin does not overlap with actin.
- During muscle contraction, both H and I bands decrease in length.