Question

The figures given here represent three different conditions of sarcomeres. Identify these conditions and select the correct option.

	$A$	$B$	$C$
(a)$\,\,$	Contracting$\,\,$	Relaxed$\,\,$	Maximally contracted$\,\,$
(b)$\,\,$	Relaxed$\,\,$	Contracting$\,\,$	Maximally contracted$\,\,$
(c)$\,\,$	Maximally contracted$\,\,$	Contracting$\,\,$	Relaxed$\,\,$
(d)$\,\,$	Relaxed$\,\,$	Contracted$\,\,$	Contracting

• A. a
• B. b
• C. c
• D. d

Answer 1

Answer: (B)

In the given figure A, the length of the two sarcomeres is normal i.e., the muscle is in relaxed state. In figure $B$, the length of sarcomeres shortens, $H$-zone narrows and size of $l$-band decreases i.e., the muscle is contracting. In figure $C$, the length of sarcomere further shortens and $H$-zone disappears and $l$-band further decreases i.e., the muscle is maximally contracted.