BIOSC 1250 Lecture Notes - Lecture 9: Phosphocreatine, Skeletal Muscle, Myocyte
Document Summary
Regulation of muscle contraction, smooth & cardiac muscle (lecture 9) * twitch: contraction of muscle fiber associated w/ a single action potential. Muscle fatigues more quickly after fused tetanus. Central fatigue: motor cortex neurons stop sending signals to motor neurons = no muscle aps: brain controls the muscle & says no, fatigue can be overwritten to some extent by the brain. Is motor neuron signal telling muscle to contract even though (cid:455)ou do(cid:374)"t (cid:449)a(cid:374)t it to. Muscle afferent neurons tell muscle to contract b/c inappropriately activated by painful stimulus. Isotonic: muscle moves the load & gets shorter. Max level of contraction (most force) at optimal sarcomere length. Too long of length = no interaction b/t actin & myosin to generate contraction. Too short of length = steric hindrance (molecules like actin get in the way of each other) Myosin has 2 forms: fast & slow (how quickly it cleaves & hydrolyzes atp = speed of cross bridge cycle)
