The ATPase activity of the myosin head is dependent on:

1. Magnesium ions

2. Manganese ions

3. Calcium ions

4. Ferric ions

The neurotransmitter released at the neuromuscular junction is:

1. Adrenaline

2. Nor-adrenaline

3. Dopamine

4. Acetylcholine

The combination of a neuron and the muscle fiber it associates with is called a/an.

1. fascicle

2. motor end plate

3. motor unit

4. myoneural junction

Consider the following statements:

I. A motor neuron along with the muscle fibres connected to it constitute a motor unit

II. The neurotransmitter released at the neuro-muscular junction is Acetylcholine.

III. Myosin head has ATPase activity.

Which of the above statements are true?

1. I and II only

2. I and III only

3. II and III only

4. I, II, and III

Prostaglandins have no role in 

1. inflammatory and allergic reactions

2. blood clotting 

3. smooth muscle contraction

4. conduction of nerve impulses.

If a stimulus, several times greater than the threshold stimulus is provided to a muscle

fibre, it will

1. Contract with a larger force

2. Contract with a smaller force

3. Contract with a same force

4. undergo tetany

Ca⁺² bind ________ in the skeletal muscles and leads to exposure of the binding site for ________ on the filament _______:

1. Troponin, myosin, actin                

2. Troponin, actin, relaxin

3. Actin, myosin, troponin                

4. Tropomysin, myosin, actin

The action potential that triggers a muscle contraction travels deep within the muscle cell by means of:

(1) Sarcoplasmic reticulum                

(2) Transverse tubules

(3) Synapse                                      

(4) Motor end plates

A motor unit is best described as:

(1) All the nerve fibres and muscle fibres in a single muscle bundle

(2) One muscle fibre and its single nerve fibre

(3) A single motor neuron and all the muscle fibres that it innervates

(4) It is the neuron which carries the message from muscle to CNS

Electrical excitation in a muscle fibre most directly causes:

(1) Movement of tropomyosin

(2) Attachment of the cross bridges to actin

(3) Release of Ca⁺² from sarcoplasmic reticulum

(4) Splitting of ATP