Sliding Filament theory Myosin and actin overlapping nature On the filament are special sites to which myosin attach

1000’s of filaments do this, what problems might arise if it doesn’t occur properly?

Slippage will occur

Transmission of neural impulse

• Involves electrical signal
• At rest the neurone is positive outside and negative inside. This is resting potential
• When a neurone receives instructions from the central nerves system, sodium ion enter the neurone causing the inside tab come and outside
• This is called action potential
• As less sodium enters the neurone and potassium Ions leaves, the neurone returns to resting potential
• An action potential in one part of the neurone causes the next part to undergo the same process, thereby the impulse is sent along the neurone towards the muscle
• A.p occurs in “all or nothing” principle. It doesn’t matter how strong the impulse is
• Speed of the impulse depends on the neurone ( myelin sheath)

Transmissions of active muscles

• Neurones communicate with muscle via a SYNAPSE. This is a gap that the impulse cant jump
• The A.P release a transmitter substance (acetyl Choline) which received by the receptors on the muscle causing a Muscle Action potential. This passes into the muscle causing the release of calcium
• In big muscles 1000’s of fibres receive instruction in smaller muscles there are fewer fibres pre neurone
• Again ‘ All or one’ of the muscle fibres will contract for a functions of second ( muscle twitch)
• The next stimulus will occur before the effect of the first has diminished hence tension rises    Wave simulation