Neuromuscular junction and sliding filaments

A neuromuscular junction is where a neuron synaptic bulb and muscle fibre connect

• True
• False

Which protein filament is attached to the "Z" line of the sacromere?

• Actin
• Myosin
• Sacromere
• Nucleus 

What is released from the scaroplasmic reticulumn  and is required to get the myosin binding sites exposed (on an actin filament)?

• Sodium
• Potassium
• Calcium
• acetylcholine

Which statement is true:
Acetylcholine is involved in:
a)Diffusing across the synaptic cleft from the axon terminal
b) Binding to receptors and ligand channels
c) Acetylcholine initiates the action potential (AP) in a muscle fibre
d) All of the above

• A
• B
• C
• D

Once the action potential has traveled along the sacrolemma, what structure takes the action potential into the interior of the muscle fibre?

• T- tublues
• Sacroplasmic reticulum
• Mitochondria
• Sacroplasm

From the previous question, is this statement True or False.
1. Action potential travels down the T- tubule
2. A voltage sensitive protein changes shape.
3. The Ca+ channel in the sacroplasmic reticulum causing a Ca+ influx into the scaroplasm.
4. This influx causes the excitation and contraction of muscles

• True
• False

What is the role of calcium in the cross bridge cycle ?

• Attaching to Troponin on the actin filament, causing a shape change. The Tropomyosin exposes the actin attachment site for myosin.
• It attaches straight to Tropomyosin on the myosin filament. 
• The calcium attaches to both Troponin and Tropomyosin at the same time, connecting the actin and myosin filaments
• Calcium is only required after the Tropomyosin has allowed myosin to bind to the exposed actin sit on the thin filament

True or False:
Acetylcholinesterase is an enzyme that breaks down Acetylcholine into two different parts.

• True
• False

True  or False:
A motor unit has multiple motor neurons that supply individual muscle fibres within a skeletal muscle 

• True
• False