The I band is a term used to refer to an area within
A sarcomere is the repeating functional unit of "striped"
or "striated" muscle.
"Striated muscle" is also known as "skeletal
muscle", "voluntary muscle", and "cardiac muscle". Its striated (stripey)
visual appearance is
due to alternating (dark) A
bands and (light) I
sizes of the H
band, and the I
band of sarcomeres are determind by, and provide information about,
the state of contraction or relaxation of the muscle tissue of which
the sacromere is a part.
This is illustrated below:
Diagram of the unit within a muscle cell that is known as a sarcomere.
band is the region between adjacent A bands,
in which there are only thin
filaments, and no thick
( Each I band extends across two adjcent sarcomeres.)