Muscular System Characteristics!

Type 1

slow oxidative, slow twitch

red in color

prolonged, sustained contractions for maintaining posture

Type 2a

fast oxidative-glycolytic, (FOG)

red in color

split ATP at very fast rate; used for walking & intermediate intensity activities

running 400m-800m

Type 2b

fast glycolytic fibers, fast-twicth

white in color

anaerobic movements for short duration; used for weight-lifting & sprinting

running 100m-200m

Type 1 as well

Which Skeletal Muscle Fiber Type is for slow, prolonged movements

Excitability

ability to respond to stimuli and produce electrical signals

Contractility

ability to shorten and generate force once excited

Extensibility

ability to stretch without damaging the tissue

Elasticity

ability to return to normal length after being extended

Thermal

ability to produce heat energy

First

Nerve impulse arrives at axon terminal which opens voltage-gated calcium channels.

Second

The presence of calcium causes the synaptic vesicles to release their contents (often acetycholine, ACh) into the synaptic cleft.

Third

ACh binds to receptors on the miscle motor end plate; this opens Na^+ channels and Na⁺ rushes into the cell.

Fourth

Inside of the muscle cell becomes more positive, triggers muscle action potential that spreads over sarcolemma and down the transverse tubules.

Fifth

The release of Ca²⁺ from the SR is triggered and the muscle cell will shorten and generat force.

Sixth

Ca²⁺ binds to troponin and causes troponintropomyosin complex to move and reveal myosin bonding sites on actin.

Seventh

The contraction cycle begins