Reflex

Summation

Twitch

EMG

Phasic Contraction

occur because repetitive stimulation results in more muscle fibres being activated to contract.

occur when the muscle is stimulated so rapidly that the action potential is not allowed enough time to return to the resting potential.

generate more force than twitch contractions because with repetitive stimulation calcium stays in the cytoplasm for longer and the cross-bridges have more time to exert their full force.

generate more force than twitch contractions because repetitive stimulation results in a build-up in the amplitude of the muscle action potentials.

activated first are of the fast glyolytic type

activated first are of the fast oxidative glyolytic type

activated first are of the slow oxidative type

activated last are of the slow oxidative type

are activated in order of size

Chiefly in smooth muscle fibres

Only from anaerobic respiration

When the muscles have exhausted their energy supply

Due to lactic acid build up

From excessive glycolysis

 only if the second action potential is bigger than the first action potential.

 because the second action potential causes more ATP to be made available to provide more energy for the contraction.

because when there is a second action potential shortly after the first one, calcium stays in the cytoplasm for longer and the cross-bridges have more time to exert their full force.

because the second action potential stimulates more muscle fibres to contract.

Slow oxidative Type I fibres

Fast glycolytic Type IIb fibres

Fast oxidative glycolytic Type IIa fibres

Fast glycolytic Type I fibres

Fast oxidative Type IIb fibres

Type IIb muscle fibres; Intermediate sized motor units; Producing Moderate force

Type IIa muscle fibres; Small motor units; Producing Low force

Type I muscle fibres; Intermediate sized motor units; Producing Moderate force

Type I muscle fibres; Intermediate sized motor units; Producing Low force

Type IIa muscle fibres; Intermediate-sized motor units; Producing Moderate force

First use rate coding and recruitment of small motor units, then of intermdiate sized motor units, and finally of large motor units

First use the mechanism of rate coding and when all motor units are activated, they then use the recruitment 

First recruit small motor units, then recruit intermdiate sized motor units, and finally use recruitment and rate coding of large motor units

First use the mechanism of recruitment and when all motor units are activated, they then use the rate coding mechanism

First use rate coding of small motor units, then rate coding of intermdiate sized motor units, and finally rate coding and recruitment of large motor units