The thick filaments are connected in the middle of the sarcomere by which structure?

The thick filaments are connected in the middle of the sarcomere by which structure?

• A. Z Disc
• B. M Line
• C. A Band
• D. I Band

Answer: (B)

In the center of each sarcomere, thick myofilaments are held together by the M line. This central protein lattice anchors and aligns adjacent thick filaments, keeping the myosin bundles in register so they can pull on the actin filaments smoothly during contraction. The Z discs mark the sarcomere boundaries and anchor thin filaments; the A band covers the length of the thick filaments plus the overlap with thin filaments; the I band contains only thin filaments and is bisected by a Z disc. So the structure that connects thick filaments in the middle is the M line.

In the center of each sarcomere, thick myofilaments are held together by the M line. This central protein lattice anchors and aligns adjacent thick filaments, keeping the myosin bundles in register so they can pull on the actin filaments smoothly during contraction. The Z discs mark the sarcomere boundaries and anchor thin filaments; the A band covers the length of the thick filaments plus the overlap with thin filaments; the I band contains only thin filaments and is bisected by a Z disc. So the structure that connects thick filaments in the middle is the M line.