Muscles A2 Flashcards
define sarcomere
distance between Z lines
what happens to sarcomere during muscle contraction
gets shorter
define I bands
light region of just actin
what happens to I bands during contraction
they get shorter
define A bands
dark region where actin and myosin overlap
what happens to A bands during contraction
stay the same length
what is hydrolysis of ATP during contraction for
provides energy to break cross bridges and detach myosin heads
allows myosin to return back to their original position
what is the role of calcium ions in contraction
binds to troponin causes tropomyosin to be displaced reveals myosin binding sites on actin allowing actomyosin cross bridges to form activates ATPase on myosin
what affects shape of calcium ion receptors
pH and temperature
role of tropomyosin
blocks myosin binding site
moves from binding site due to Ca+
allowing cross bridges to form
what is the arrangement of the sliding filament theory
when contracted, myosin and actin overlap
actin moves along myosin
actin pulls Z lines closer together
what are fast twitch muscles used for
explosive movement
what are slow twitch muscles used for
endurance
features of a fast twitch muscle
enzymes for anaerobic respiration
phosphocreatine for ATP regeneration
higher quantity of myosin for powerful contractions
features of a slow twitch muscle
lots of mitochondria for aerobic respiration
good supply of glycogen
rich capillary network to provide oxygen
