What are the functions of the muscle system?
Produce skeletal movement Maintain posture/body position Support soft tissue Thermoregulation Guards entrances and exits
made of groups of muscle fibers (muscle cells)
muscle fascicles
Covers whole muscle; separates muscle from surrounding tissues and organs
epimysium
Around muscle fascicle, divides skeletal muscle into series of fascicles, contains blood vessels and nerves which will serve the muscle fibers located within
perimysium
surrounds individual muscle fiber
Loosely interconnects adjacent muscle fibers
endomysium
What does the endomysium contain?
capillary network, myosatellite, nerve fibers
Bundle of dense regular connective tissue attaching muscle to bone
tendon
Broad sheet of dense regular connective tissue providing a larger attachment which may include more than one bone
aponeurosis
dense irregular connective tissue sheet external to the epimysium, separates muscle from each other
deep fascia
areolar and adipose connective tissue sheet; separates muscle from skin
superficial fascia
cell membrane of a muscle fiber
sarcolemma
cytoplasm of the muscle fiber
sarcoplasm
Narrow tubes continuous with the sarcolemma and extend into the sarcolemma
Transverse tubules
Tubular network surrounding each myofibril for storage of calcium ions
sarcoplasmic reticulum
end of SR which has enlarged and fused with the t-tubule
terminal cisternae
T-tubule + Terminal Cisternae on each side
triad
Actively move more calcium into the SR from sarcoplasm
ion pumps
Open in response to electrical stimulus allowing calcium out of the SR.
calcium gated ion channels
What does the membrane contain?
ion pumps, calcium gated ion channels,
bundles of myofilaments, protein filaments, surrounded by transverse tubules running the length of the muscle fiber
myofibrils
protein filaments necessary for muscle contraction
myofilament
What are the 2 types of myofilament?
thick and thin
primary protein molecule of thick filament
myosin
long interwoven polypeptide chains that bind to other myosin molecules
myosin tail
contain two globular protein subunits and will interact with thin filament during contraction forming a crossbridge
myosin head
Elastic core extending past myosin which recoils after stretching
titin (connectin)
primary protein of the thin filament
actin
What makes up filamentous actin?
strands of globular actin
Long protein holding the two strands of F-actin together
nebulin
Long double stranded protein molecule which blocks myosin bind sites on actin when muscles are at rest
tropomyosin
What does troponin bind with?
Tropomyosin
Actin
Caclium ions when they become present
Attachment for thin filaments which interconnects neighboring sarcomeres
actinin
Repeating functional units of myofilaments extended along myofibrils
sarcomeres
Thin filaments only in a sarcomere
I-band
Center of I-band where thin filaments are anchored into actinin
Z line
Location of thick filaments
A Band
Where thick filaments are interspersed with thin filaments
Zone of overlap
Only thick filaments in A band
H Band
Middle of H band which connects thick filaments
M line
When skeletal muscle fibers contract the thin filaments slide past thick filaments during contraction
Sliding filament theory
H bands get ___ when contraction occurs
Smaller
I bands get ___ when contraction occurs
smaller
Z lines move _____ when contraction occurs
closer together
Zone of overlap gets ___ when contraction occurs
Larger