
What is sarcomere?

Important Questions on Muscular and Skeletal System

During muscular contraction which of the following events occur?
(a) 'H' zone disappears
(b) 'A' band widens
(c) 'I' band reduces in width
(d) Myosin hydrolyzes ATP, releasing the ADP and Pi
(e) Z-lines attached to actins are pulled inwards.
Choose the correct answer from the options given below.


Assertion (A): Skeletal muscles have very limited power of regeneration.
Reason (R): Satellite cells are present in them.
The correct option among the following is



(i) Muscles show three essential properties such as excitability, conductivity and contractility.
(ii) Muscular tissue is endodermal in origin except muscle of iris and ciliary body.
(iii) The cytoplasm of muscle fibre has several myofibrils.
(iv) Skeletal muscles exhibit slow and prolonged contractions.
(v) The regular arrangement of myosin and actin filaments is responsible for alternate dark and light bands of striated muscle.

Reason (R): The above said molecules have a role in masking and unmasking the active sites on actin.

-line
-line
-zone
-band




Statement II: Actin is a motor protein that is able to convert chemical energy into mechanical energy



How does muscle cells change their shape?




