Skeletal Muscle Mechanisms Flashcards
the response of a muscle to a single stimulation can be?
strong or weak
long or short
what happens to the motor units in a muscle twitch?
motor neuron and fibres innervated
what are some causes of a muscle twitch?
fatigue
stress and anixety
dehydration
what are the 3 phases of the muscle twtich?
latent period
contraction
relaxtion
what happens in the latent period?
time from action potential to onset of muscle contraction
what happens in the latent period (bioechmical explanation)
the action potential travels along the sacoleema (muscle cell membrane) and into the T- tubles which releases calcium ions from the sacroplasmic reticlum
what is the sacoleema
muscle cell membrane
what happens in the contraction phase?
calcium ions are released, binding to troponin and causing a conformational change. This change enables the interaction between myosin heads and actin filaments, leading to the sliding of these filaments. As a result, sarcomeres shorten, generating tension in the muscle and ultimately causing muscle contraction.
what happens in the relaxation phase?
The calcium ions are actively pumped back into the sarcoplasmic reticulum
troponin-tropomyosin complex prevents further interaction between actin and myosin, allowing the muscle to relax.
what are the 2 main types of muscle twitch
isotonic and isometric
explain the isotonic muscle twitch
muscle length changes
tension overcomes load
concentric or eccentric
explain isometric muscle twitch
the muscle length is unchanged
tension develops but load is not moved
process of isotonic twitch contraction?
cross birdges form, thin filaments slide across the thick filaments
process of ismoetric twitch contraction?
cross bridges form and no sliding of thin filaments
