During muscle contraction, the length of all the following gets reduced except:

1. H-Zone

2. A-Band

3. I-Band

4. Sacromere

Which of the following is correct about the given figure?

(1) The length of the thick and thin myofilaments has changed.

(2) Length of both anisotropic and isotropic band has changed.

(3) The myosin cross-bridges move on the surface of actin and the thin and thick myofilaments slide past each other.

(4) Length of the sacromere remains same.

During muscular contraction, which of the following events occur?

(i)   H-zone disappears

(ii)  A band widens

(iii)  I band shortens

(iv)  Width of A band is unaffected

(v)  M line and Z line come closer

(1)  (i),(iii),(iv) and (v)

(2)  (i),(ii) and (v)

(3)  (ii),(iv) and (v)

(4)  (i),(ii) and (iii).

Which of the following is true for the labelled parts in the figure below?

(1) A - Z-line              - located at centre of I - band

(2) B - Thin filament   - occurs in A-band only

(3) C - Thick filament  - confined to I-band

(4) D - H-zone           - located at centre of M-line

The H-Zone in the skeletal muscle fibre is due to 

(1) the central gap between actin filaments extending through myosin filaments in the A-band

(2) extension of myosin filaments in the central portion of the A-band

(3) the absence of myofibrils in the central portion of A-band

(4) the central gap between myosin filaments in the A-band