Arrange the following steps of muscle contraction in the sequence of events occurring first I. Receptor sites on sarcolemma II. Nerve impulse III. Release of IV. Acetylcholine release V. Shortening of sarcomere VI. Synaptic cleft VII. Spread of impulse over sarcolemma on T-tubule The correct option is
II → IV → VI → I → VII → III → V
II → IV → I → VI → VII → III → V
II → IV → I → VI → VII → V → III
IV → II → I → VI → VII → V → III
Related Questions
Low level of ions in muscles result in
Rapid spasms
Wild contractions
Both (a) or (b)
None of the above
A genetic mutation affects the $Ca^{2+}$$-ATPase pumps in the sarcoplasmic reticulum (SR). Which of the following would be the MOST likely direct consequence of this mutation in muscle fibers?
Inhibition of action potential propagation along the sarcolemma
Reduced release of acetylcholine at the neuromuscular junction
Prolonged muscle contraction due to impaired $Ca^{2+}$$ removal from the sarcoplasm
Inability of troponin to bind $Ca^{2+}$$
At motor-end plate the following transmitters is released
acetylcholine
bradykinin
serotonin
histamine
Statements about the mechanism of muscle contraction are given below.
I. Acetylcholine is released when the neural signal reaches the motor end plate.
II. Muscle contraction is initiated by a signal sent by CNS via a sensory neuron.
III. During muscle contraction isotropic band gets elongated.
IV. Repeated activation of the muscles can lead to lactic acid accumulation.
Identify the correct statement.
I and II
II and III
I and IV
II and IV
Action potential in sarcolemma of muscles causes the release of
Arrange the following steps of muscle contraction in the sequence of events occurring first I. Receptor sites on sarcolemma II. Nerve impulse III. Release of IV. Acetylcholine release V. Shortening of sarcomere VI. Synaptic cleft VII. Spread of impulse over sarcolemma on T-tubule The correct option is
II → IV → VI → I → VII → III → V
II → IV → I → VI → VII → III → V
II → IV → I → VI → VII → V → III
IV → II → I → VI → VII → V → III
Which protein blocks the myosin-binding sites on actin in a relaxed muscle?
Tropomyosin
Troponin
Myosin
Actin
Calcium is important in skeletal muscle contraction because it
Prevents the formation of bonds between the myosin cross bridge and the actin filament.
Binds to troponin to remove the masking of active sites on actin myosin
Detaches the myosin head from the actin filament.
Activates the myosin ATPase by Binding to it.
What happens immediately after the power stroke in the cross-bridge cycle?
ATP binds to the myosin head.
The myosin head reattaches to actin.
Calcium ions are released from the sarcoplasmic reticulum.
Acetylcholine is released into the synaptic cleft.
Read the following statements w.r.t. muscle contraction and choose the option that states all the correct statements.
a. Actin and myosin filaments do not get short but rather slide passes each other
b. The size of A-band reduces c. Length of H-zone decreases
a and b
a, b and c
a and c
Only a
