IBSEHS Topic 4.1 Synaptic Transmition

how neurons communicate with muscle fibres

Step 1

Step 1

Action potential (nerve impulse) arrives at the axon terminal

Step 2

Calcium channels open up and allows calcium ions from the outside to enter the axon terminal

Step 3

Increased calcium ions on the inside cause the synaptic vesicles to move towards the end of the axon terminal

Step 4

Synaptic vesicles fuse with the membrane and release acetylcholine (Ach) into the synaptic cleft

Step 5

Ach travels across synaptic cleft towards the muscle fibre and binds to the receptors

Step 6

A response is triggered in the muscle fibre & it generates its own action potential

Step 7

The action potential travels through the muscle fibre

Step 8

Ach cannot remain in the synaptic cleft; an enzyme called AchE breaks down Ach

Slow twitch fibres

More for endurance, long lasting energy

Fast twitch fibres

more for sudden bursts of energy but gets tired quickly

Aerobic

Process that requires oxygen

Anaerobic

Process that does not require oxygen