ch 9- muscle n muscle tissue Flashcards
62 slides
myo
muscle tissue
sarco
striped muscle
functions of muscles
movement, posture and position, joint stability, maintaining body temperature
muscle characteristics
excitebaility, contractility, extensibility, elasticity. all muscles have all 4
skeletal muscle tissue
voluntary, control how much and when used. moves body parts, striated and multinucleate. uses skeleton like puppet. creates most force, needs most rest. adaptable to force, we say how much
smooth muscle tissue
involuntary, moves fluids and substances, no striations and uninucleate. lines hollow organ
cardiac muscle tissue
involunatury muscle tissue, moves blood thru body, pacemaker cells set the rate, striated, uninucleate. ONLY HOLLOW ORGAN WITHOUT SMOOTHMUSCLE TISSUE IS THE HEART
innervation of skeletal muscle tissue
each muscle fiber synapses w one motor nerve. but, each muscle can be served by multiple motor neurons. nerve ending controls activity
vascularization of skeletal muscle tissue
each muscle has 1 artery and 1 vein, brings nutrients and removes waste, a lot of ATP so a lot of waste
connective tissue sheaths
support muscle, hold muscle together
connective tissue layers
endomysium (inner most layer isolates individual muscle fibers), perimysium (middle layer, forms fascicles with groups of muscle fibers), epimysium (outermost layer, surrounds entire muscle, continues with tendon to attach bone)
imagine picture of muscle. what is order of stuff in it
TENDON TO EPIMYSIUM TO PERIMYSIUM TO ENDOMYSIUM TO MUSLCE FIBER AND ONE MUSCLE FIBERS GOT ALL THOSE MYOFIBRILS
skeletal muscle attachments
can be direct or indirect. muscles use our bones like levers, so muscle attaches to bone
direct attachment
epimysium of muscle fuses directly to bone or cartilage, no tendon here so prone to damage
indirect attachment
has tendons, which are band of connective fibrous tissue connecting muscle to bone.
more common skeletal muscle attachment
indirect
points of attachment for bone
origin and insertion
origin
muscle attaches to less movable bone, proximal portion.
insertion
muscle attaches to a moveable bone, distal
myocytes
largest/longest cells in body- muscle fibers
sarcolemma
plasma membrane of muscle fibers
sarcoplasm
cytoplasm of muscle fibers. has many glycosomes and myoglobins
glycosomes
organelles that store glycogen, polysaccharide. glycogen is needed to ATP bc it gets turned into glucose.
myoglobin
stores oxygen, O2 needed for ATP production. makes it so O2 is available during contraction.
myofilaments
protein filaments in muscle tissue, has thick and thin
thick filament
myosin
thin filament
actin
how is tension created in a muscle
actin and myosin interact!
myosin filaments whatrthey
thicker, have 2 heavy chains, and myosin head at end of each chain. myosin head has 2 bind sites: 1 head for ATP 1 for actin.the heavy chains twist around each other.
why r myosin headsneeded
links two myofilaments during contraction
actin filaments
chains of G protein and myosin binding sites
actin filament function
myosin head binds myosin site of actin during contraction, regulatory proteins of actin control if or when the myosin head can bind- PREVENTS INAPPROPRIATE MOVEMENT
regulator proteins in actin filaments
tropomyosin and troponin
tropomyosin
arranged along length of thin filament, blocks myosin binding sites on actin filament when muscle is relaxed. no bad interactions then!
troponin
globular protein that is associated w tropomyosin, binds tropomyosin to position it on actin filament. prevents and allows contraction
myofibrils
rod like organelles inside muscle cells. bands of actin and myosin. each muscle has several myofibrils
what creates striations on skeletal muscle
myofilament overlap to produce dark bands
myofibrils r made up of…
A band and I band
A band
myofibril region where actin and myosin overlap
I band
ONLY actin filaments here in myofibril.
Z disc
holds actin filaments in place, prevents movement.
sarcomere
A and I bands create it, between neighboring Z discs. one of them is an entire A band and 1/2 I band on each side
why is sarcomere important
smallest contractile unit of skeletal muscle tissue. if it shortens, contraction happens!
T-tubules
extension of sarcolemma wraps deeper myofibrils, helps stimulate the deep ones. increases SA of sarcolemma, so a change in membrane potential can reach even deep ones
sarcoplasmic reticulum
wraps myofibrils, stores and releases Ca2+ for muscle contraction and relaxation. forms terminal cisterns. AP travels down to stimulate Ca releasing.
terminal cisterns
thickening, where Ca is released.
one skeletal muscle cell is innervated by
one motor neuron
neuromuscular junction
site of synapse between somatic motor neuron and muscle fiber. releases ACh which will stimulate muscle fiber and depolarize sarcolemma