Muscle Movement Lab

Question 1

what is a neuromuscular joint?

Answer 1

the specialised synapse between the motor neuron and muscle fibre.

Question 2

what makes up the neuromuscular junction?

Answer 2

axon terminal, synaptic cleft and motor end plate of the muscle fibre

Question 3

how does signal transmission work at the NMJ’s?

Answer 3

-action potentials trigger release of acetylcholine in synaptic cleft
-ach diffuses through junctional cleft and binds to nicotinic ach receptors at motor end plate
The bound receptors open cation-selective ion channels, which depolarizes the muscle end-plate and leads to the release of calcium from the sarcoplasmic reticulum. The increased cytosolic calcium sets in motion the biochemical events that underlie contraction. Acetylcholine is rapidly hydrolyzed by acetylcholinesterase, which terminates the muscle contraction signals.

Question 4

what is eccentric contraction?

Answer 4

downward movement occurs when a force applied to the muscle exceeds the momentary force produced by the muscle itself, resulting in the forced lengthening of the muscle-tendon system while contracting

Question 5

what is concentric contraction?

Answer 5

he muscle tension rises to meet the resistance then remains stable as the muscle shortens.