Sarcomere Structures

Question 1

What are Z-Discs/Lines?

Answer 1

Boundaries of Sarcomere

Z-Discs/Lines define the limits of a sarcomere in muscle fibers.

Question 2

What are I-Bands?

Answer 2

Regions where there are thin filaments ONLY

I-Bands are zones in the sarcomere that contain only actin filaments.

Question 3

What are A-Bands?

Answer 3

Full length of the thick filaments

A-Bands contain both thick and thin filaments, but the length corresponds to the thick filaments.

Question 4

What is the H-Zone?

Answer 4

Part of the A-Band; area where thick filaments do not overlap with thin filaments

The H-Zone is visible in the A-Band and indicates the space where only thick filaments are present.

Question 5

What is the M-Line?

Answer 5

At the exact center of the sarcomere; consists of the protein myomesin

The M-Line helps to anchor the thick filaments in place within the sarcomere.