2 What role does ATP play in muscle contraction and rigor mortis? 12.2 Skeletal Muscle Fiber ContractionWhat role does ATP play in muscle contraction and rigor mortis?ATP is needed to attach and detach the myosin heads from actin.After death, muscle cells continue to produce ATP through ______________ and muscle cells can continue to contract.When ATP runs out, some myosin heads are still attached and cannot detach, causing rigor mortis.Rigor mortis and body ___________ may be used to estimate time of death.
3 Terms to describe whole muscle contraction _________ – a nerve fiber and all of the muscle fibers it stimulates____________ – a single contraction lasting a fraction of a second____________ – an increase in muscle contraction until the maximal sustained contraction is reached
4 Terms to describe whole muscle contraction _________ – maximal sustained contraction___________ – a continuous, partial contraction of alternate muscle fibers causing the muscle to look firm4
7 What are the sources of ATP for muscle contraction? 12.3 Whole Muscle ContractionWhat are the sources of ATP for muscle contraction?Limited amounts of ATP are stored in muscle fibers.Creatine phosphate pathway (CP) – ________ way to acquire ATP but only sustains a cell for _______; builds up when a muscle is restingFermentation – fast-acting but results in _______ build upCellular respiration (aerobic) – not an immediate source of ATP but the best _________ source
9 Muscle fibers come in 2 forms 12.3 Whole Muscle ContractionMuscle fibers come in 2 formsFast-twitch fibersRely on CP and fermentation (anaerobic)Adapted for strengthLight in colorFew mitochondriaLittle or no myoglobinFewer blood vessels than slow-twitch
10 Muscle fibers come in 2 forms 12.3 Whole Muscle ContractionMuscle fibers come in 2 formsSlow-twitch fibersRely on aerobic respirationAdapted for enduranceDark in colorMany mitochondriaMyoglobinMany blood vessels10