Sources of ATP, Types of Muscle Fibers, and Types of Contractions

Mechanisms to restore ATP

1. Creatine Phosphate

2. Anaerobic Glycolysis

3. Aerobic Respiration

Creatine Phosphate

molecule that store energy in its phosphate bonds

Anerobic Glycolysis

anaerobic process that breaks down glucose to produce ATP;when creatine phosphate is depleted, it turns to glycolysis for ATP; can’t generate ATP as quickly as creatine phosphate

pyruvic acid

used in aerobic respiration or when oxygen levels are low, converted to lactic acid

lactic acid

contributes to muscle fatigue

Aerobic Respiration

breakdown of glucose or other nutrients in the presence of oxyen to produce carbon dioxide, water, and ATP; 36 ATP per molecule of glucose

Oxygen Debt

amount of oxygen needed to compensate for ATP produced without oxygen during muscle contraction; converts lactic acid to pyruvic acid

Isotonic Contractions

the tension in the muscle stays constant, as load is moved as the length of the muscle changes(shortens)

Concentric Contraction

type of isotonic contraction; involves the muscle shortening to move a load

Eccentric Contraction

type of isotonic contraction; muscle tension diminishes and the muscle lengthens

Isometric Contraction

muscle produces tension without changing the angle of a skeletal joint; maintains posture

Types of skeletal muscle fibers

slow oxidative(SO), fast oxidative(FO), fast glycolytic(FG)

slow oxidative(so)

fibers contract relatively slowly and use aerobic respiration to produce ATP

fast oxidative(fo)

fibers have fast contractions and primarily use aerobic respiration, but because they may switch to anaerobic respiration, can fatigue more quickly than so fibers

fast glycolytic (fg)

fibers have fast contractions and primarily use anaerobic glycolysis

so fibers

red color; many mitochondria; lots of blood capillaries; possess myoglobin; maintain posture

fo fibers

lighter color than so fibers; between fast and slow fibers; don’t posses high amounts of myoglobin; movements more extensive than maintaining posture like walking

fg fibers

white color; high amounts of glycogen; high levels of tension; not a lot of myoglobin; used for rapid, powerful, forceful contractions