PHGY 214 Lecture Notes - Lecture 4: Phosphocreatine, Muscle Fatigue, Rigor Mortis
15 Nov 2017
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Atp later split to provide energy for next stroke: active transport of ca+ back into sr during relaxation depends on energy derived from breakdown of atp. Contractile activity in skeletal muscle cannot be maintained at given level indefinitely. Tension declines as fatigue sets in (2 types of fatigue: muscle fatigue aka. Muscle fatigue: when exercising muscle cannot respond to stimulation with same degree of contractile activity, defence mechanism that protects muscle from reaching point at which it cannot produce atp. Neuromuscular fatigue: inability of active motor neurons to synthesize acetylcholine rapidly enough to sustain chemical transmission of aps from motor neurons to muscles, can be produced experimentally but doesn"t occur under normal, occurs in exercise physiological conditions. Breathe deeply and quickly post exercise because need for o2 is elevated: termed excess post-exercise oxygen consumption (epoc) Increased speed of these chemical rxns partially accounts for. Muscle fibres in single m. u. are homogenous in contractile and metabolic function.
