The motor unit actually has

1. Motor neuron

2. Motor neuron+ muscle fibres

3. Only muscle fibres

4. It can be both 2 and 3

Muscle Contraction is initiated by

1. A signal sent by CNS via a motor neuron

2. A signal sent by PNS via a motor neuron

3. A signal sent by ANS via efferent neuro

4. A signal sent by ANS via efferent neuron

Neuromuscular junction or motor endplate is

1. The junction between a motor neuron and the sarcolemma of the muscle fiber

2. The junction between a motor neuron and sensory neuron

3. The junction between the sensory neuron and the sarcolemma of the muscle fibre

4. Both 1 and 3

A neural signal reaching this junction releases a neurotransmitter…………. Which generates an action potential in the ………..

1. Acetyl choline, Sarcolemma

2. Inositol, Sarcolemma

3. GABA, Sarcoplasmic reticulum

4. GABA, Sarcoplasm

The calcium ions released in sarcoplasm will bind to

1. Tropomyosin

2. Troponin

3. Actin

4. Meromyosin

The binding of troponin on actin Filaments actually unmasks the …..

1. Active site for Tropomyosin

2. Active site for ATP

3. Active site for Myosin

4. Active site for troponin

The binding of calcium to troponin actually indicates

1. Unmasking of Myosin binding site over meromyosin

2. Unmasking of Myosin binding site over actin

3. Unmasking of the actin-binding site over Myosin

4. Unmasking of actin-binding site over tropomyosin

…………… projects outwards at regular …….. from each other from the surface of polymerized Myosin Filaments and is also known as …….

1. Head and short arm, angle, cross arm

2. Head and short arm, distance, cross arm

3. Both 1 and 2

4. Head and short arm, distance, LMM

The cross-bridge formation actually involves

1. ATP hydrolysis

2. Binding of Myosin head to the exposed active sites for myosin

3. Both A and B

4. None of these

During contraction of muscle fibers which of the following does not happen?

1. The length of the A band gets reduced

2. The attached actin Filaments are pulled towards the centre of A band

3. The Z line attached to actin Filaments is pulled inward

4. Shortening of sarcomere