lecture 17 Flashcards
skeletal muscles are critical for most
behaviors including breathing, moving, and talking VOLUNTARY MOVEMENTS and REFLEXES
skeletal muscles are very
organized
what is the contractile unit of a skeletal muscle
sarcomere
what is the level of organization for skeletal muscles
muscle -> muscle cell/fiber -> myofibril -> sarcomere
what tissues do muscles have
muscle tissue, connective tissue, nervous tissue
where do skeletal muscles connect to
to the bone or either side of a joint
muscles can only what kind of movement
contract and relax
muscles work in what kind of pairs
opposing pairs
what do muscles need to do to create bidirectional movement
there needs to be a coordinated relaxation/contraction around joint
the skeletal muscles are in control by the what
somatic nervous system
what do skeletal muscles and cardiac muscles have in common
they are striated
the cardiac muscle is controlled by the
autonomic nervous system
how do skeletal and cardiac muscles differ
skeletal: multiple nucleus and somatic NS cardiac: one nucleus and autonomic NS
what are cardiac myocytes
cardiac muscle cells
what are the four specializations that cardiac cells do
intercalated discs, gap junctions, pacemaker cells, long action potential
intercalated discs
mechanically connect adjacent cells
gap junctions
allows AP’s to move between adjacent cells
pacemaker cells
endogenously generate contraction signal AP
long action potential
ensures muscles have time to relax before next AP
what type of cells initiate heart contractions
pacemaker and conducting cells
the heartbeat is
myogenic
myogenic
regulated by the muscle
what can the ANS alter in cardiac muscle cells
the ANS can alter the rate of contraction but it is not necessary for their function
sinoatrial node
specialized muscle fibers located in the right atrium of the heart initiates the heartbeat
where is the smooth muscle located and what does it do
it lines many hallow organs and generate long sustained contractions or waves of contractions (gut, uterus, blood vessels)
many smooth muscles are connected by (same as cardiac cells)
gap junctions
smooth muscles do what to blood vessels
vasocontraction and vasodilatation
smooth muscles are different from skeletal and cardiac because
they are not striated and contract in all directions
smooth muscles can contract for long periods of time while
conserving ATP
smooth muscles have no
sarcomere
