Muscular System Questions Flashcards
structural and functional unit of a myofibril; contains actin and myosin filaments
sarcomere
end of a muscle attached to a movable bone
insertion
sustained maximal muscle contraction
tetanus
contraction of muscles at death due to lack of ATP
rigor mortis
stretching or tearing of a muscle
strain
impulses that move down the T system of a muscle fiber most directly cause
release of CA2+ from the sarcoplasmic reticulum
which of the following statements about cross-bridges is false?
a. they are composed of myosin
b. they bind to ATP after they detach from actin
c. they contain an ATPase
d. they split ATP before they attach to actin
they bind to ATP after they detach from actin
which statement about sarcomere contraction is incorrect
a. the A bands shorten
b. the H zones shorten
c. the I bands shorten
d. the sarcomeres shorten
the A bands shorten
which muscle would have motor units with the lowest innervation ratio
muscles that move the fingers
the thick filaments of a muscle fiber are made up of
myosin
as ADP and P are released from a myosin head
actin filaments move toward the H zone, myosin cross-bridges pull the thin filaments, a sarcomere shortens
which of these is a direct source of energy for muscle contraction
ATP
when muscles contract
the H zone disappears
nervous stimulation of muscles
occurs at neuromuscular junction, results in an impulse that travels down the T system, causes calcium to be released from expanded regions of the sarcoplasmic reticulum
in a muscle fiber
the T system causes release of Ca2+ from the sarcoplasmic reticulum
