Muscle Physiology

Question 1

Name the 2 main types of protein found in a muscle fibre

Answer 1

Actin and Myosin

Question 2

What is the name given to a ‘unit’ of Actin and Myosin filaments

Answer 2

Sarcomere

Question 3

The Thick filament consists of mainly?

Answer 3

Myosin

Question 4

The Thin filament consists mainly of?

Answer 4

Actin

Question 5

What 2 other proteins are located on the Thin filament?

Answer 5

Troponin and Tropomyosin

Question 6

How many Myosin heads are located on each cross-bridge

Answer 6

2

Question 7

The presence of what ion is required to free the myosin binding site.

Answer 7

Calcium

Question 8

Calcium binds to which protein?

Answer 8

Troponin

Question 9

Which molecule is required to power the myosin/actin cross-bridge movement

Answer 9

ATP

Question 10

What is the definition of a motor unit?

Answer 10

A motor unit is the name for a motor neurone plus the muscle fibres it innervates

Question 11

What is the principle Neurotransmitter used at the motor end plate

Answer 11

Acetylcholine

Question 12

The action of Acetylcholine at the motor end plate results in the influx of which ion into the muscle cell?

Answer 12

Sodium

Question 13

Name 1 drug/compound that acts at the Nicotinic ACh receptor?

Answer 13

Curare - Competitively inhibits the ACh receptors preventing formation of an End-Plate Potential (EPP)
Botox - Blocks the release of ACh from the nerve terminal by inhibiting vesicle fusion with the presynaptic membrane.

Question 14

Name the 3 ways a muscle fibre can form ATP

Answer 14

Phosphorylation of ADP by Creatine Phosphate
Oxidative phosphorylation of ADP in mitochondria
Phosphorylation of ADP via the Glycolytic pathway in the cytosol