muscle tissues Flashcards
why are the tissues in the muscular system unique?
they are able to contract, producing movement
the muscular system provides what four things (JH PM)
stabilizes joints, generates heat, maintains posture, and provides movement
all muscle tissues have these four characteristics (ECEE)
excitability, contractibility, extensibility, and elasticity
skeletal muscle facts
- connected to bones
- cylindrical
- striated
- multi-nucleated
- voluntary
- contracts slow/very quickly
cardiac muscle facts
- found in heart
- branched
- striated
- uni-nucleated
- involuntary
- mostly slow and steady (unless exercising)
smooth muscle facts
- found in walls of internal organs
- arranged in uniform layers
- non-striated
- uni-nucleated
- involuntary
- slow over periods of long time
order of muscle from outter to inner
epimysium, muscle, perimysium, fascicle, endomysium, muscle fibers, myofibrils, myofilaments (actin and myosin)
muscle definition
skeletal muscle attached to bone by tendons made of many bundles of fibers
fascicle definition
bundles with in muscles
muscle fiber definition
long, thin muscle cells, each is covered by sarcoplasmic reticulum, which transmits impulses to muscle fibers
myofibril definition
thread-like organelles of the muscle fibers, structured in long, striated units called sarcomeres
myofilament definition
actin (thin) and myosin (thick) make up the sliding filament model of the muscle. Responsible for contracting activity of muscle fibers
what works together to produced a muscle contraction?
actin and myosin
where are actin and myosin attached to each other
z-line
what is the space between the z-lines called?
sarcomere
what is the line called that the actin and myosin pull the muscle fiber to called?
m-line
sliding filament theory
- nerve impulses are sent to muscle fibers to begin contraction
- myosin filaments have rounded extensions called heads
- these heads attach to the twisted actin filaments and pull on them
- the z-lines get closer together and the sarcomere gets shorter
where does the energy come from that fuels the sliding filament theory
atp
each time a myosin filament engages with an actin filament, how many atp molecules are used?
1
the contraction of muscles requires:
plenty of atp molecules
muscles are either — or —
- contracted or relaxed
- the “gentleness” or “strength” of a muscle is determined by the number of fibers engaged
atp is formed through?
cellular respiration
the process of cellular respiration depends on…?
the presence of oxygen
when muscles dont get enough atp they become…?
fatigued
how do muscles become fatigued?
intense exercise, muscle fatigue (ATP is no longer being efficiently used), anaerobic respiration (muscles begin to burn, causing you to stop), and oxygen debt
what are some of the criteria to name muscles?
size, shape, location, orientation, origin and insertion, number of origins (heads) on muscles, function
muscles are attached to bones by …?
tendons
origin
attachment of the tendon to the more stationary bone
insertion
attachment of the tendon to the more movable bone
belly
middle of the bone
muscles work in pairs
prime mover and antagonists
prime mover
muscle doing the action (contracting)
synergists
muscles that help in that same direction
antagonist
opposing muscle relaxing during motion
