Chapter 9 - Muscle Fibers Types

slow twitch

type 1 twitch; contract more slowly, smaller in diameter, better blood supply, more mitochondria, more fatigue-resistant, large amount of myoglobin

fast twitch

type ll twitch; respond rapidly to nervous stimulation, contain myosin that can break down ATP more rapidly, less blood supply, fewer and smaller mitochondria

effects in exercise

change in size of muscle fibers

hypertrophy

increase in muscle size; increase in myofibrils, increase in nuclei due to fusion of satellite cells

atrophy

decrease in muscle size; in severe situations cells die

exercise

metabolic rate and heat production increase during this

post-exercise

metabolic rate stays high due to oxygen debt during this

shivering

uncoordinated contraction of muscle fibers resulting in shaking and heat production