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

ATP provides energy for muscle contraction by allowing for:

1. An action potential formation in the muscle cell

2. Cross-bridge attachment of myosin to actin

3. Cross-bridge detachment of myosin from actin

4. Release of Ca⁺² from sarcoplasmic reticulum

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

The energy for muscle contraction is most directly obtained from:

(1) Phosphocreatine                          

(2) ATP

(3) Anaerobic respiration                   

(4) Aerobic respiration

Put the following phrases in proper order to describe what occurs at the neuromuscular junction to trigger muscle contraction:

1. II, IV, I, VI, VII, III, V           

2. II, IV, VI, I, VII, III, V

3. I, II, III, IV, V, VI, VII             

4. VII, VI, V, IV, III, II, I

Go through the following diagram describing muscle contraction:

Now identify A to E:
(1) A - Cross bridge, B - Cross bridge formation, C - Breaking of cross bridge, D - Sliding (rotation), E - ATP

(2) A - Cross bridge, B - Cross bridge formation, C - Sliding / rotation, D - Breaking of cross bridge, E - ATP

(3) A - Cross bridge, B - Breaking of Cross bridge, C - sliding / rotation, D - Cross bridge formation, E - AMP

(4) A - Cross bridge, B - Cross bridge formation, C - Sliding / rotation, D - ADP, E - Breaking of cross bridge

The muscle band that remains unchanged during muscle contraction and relaxation of the skeletal muscle is:

(1) I                     

(2) A                    

(3) H                    

(4) Z-line

The compound or pigment acting as an oxygen store in skeletal muscles is:

(1) Myoglobin                                    

(2) Haemoglobin

(3) Myokinase or ATP                         

(4) Cytochrome

I. Number of mitochondria less.
II. Number of mitochondria more
III. Sarcoplasmic reticulum is abundant
IV. Myoglobin content high
V. Sarcoplasmic reticulum moderate
VI. Aerobic muscles
VII. Depend on anaerobic respiration for energy
VIII. Less myoglobin content
A. Red muscles B. White muscles
Identify above (I to VIII) traits as characteristic of A and B types of muscles:
(1) A - I, III, VII, VIII; B - II, IV, V, VI

(2) A - II, IV, V, VI; B - I, III, VII, VIII

(3) A - I, III, IV, VII; B - II, V, VI, VIII

(4) A - II, V, VI, VIII; B - I, III, IV, VII