Lesson 5 Muscle Physiology
No description yet. This curated deck is ready for daily study.
Card preview (24)
What is the epimysium?
connective tissue that surrounds the muscle
What is a muscle fascicle?
bundles of muscle fibers surrounded by perimysium
What does perimysium surround and what runs under this layer?
muscle fascicles nerves and vasculature run through this area
What connective tissue surrounds each individual muscle fiber?
endomysium
What are the thick and thin filaments of muscle fibers?
thick: myosin thin: actin, tropomyosin, troponin
What is the order from deepest to outermost layers of muscle?
fibers > endomysium > fascicles > perimysium > epimysium
What are the structure proteins in muscle fibers?
titin, desmin, and dystrophin
What is the z line of a sarcomere?
provides stability to muscle fibers, connecting adjacent actin filaments
What is an M band of the sarcomere?
bisects the central portion of the sarcomere, providing support for the myosin filaments, middle
What is the I band?
location of only thin filaments
What is the A band?
where actin and myosin overlap
What is the H zone?
only thick filament
What does the sliding filament theory explain?
how muscles contract to produce force
What happens during the cross bridge formation of sliding filament theory?
calcium binds to troponin, shifting tropomyosin which exposes myosin binding sites myosin binds to actin
What happens during the power stroke of sliding filament theory?
myosin head pivots and pulls actin filament towards M-line, causing a contraction
What is released after the power stroke?
ADP and phosphate after breaking down ATP
What happens during cross bridge detachment of sliding filament theory?
atp binds to myosin to cause release from actin
What happens during the reactivation of myosin step of the sliding filament theory?
ATP hydrolyzed into ADP and P to reset myosin head
What is excitation-contraction coupling steps?
• action potential generated and sent down T-tubules, due to ACh release • action potential triggers calcium release into sarcoplasmic reticulum • calcium binds to troponin • contraction • removal of calcium • tropomyosin block restored
What is oxidative capacity?
a property that reflects a muscle fibers ability to generate ATP from aerobic metabolism
What determines a muscle fibers oxidative capacity?
mitochondria content, amount of myoglobin, and capillary density
What is myosin isoform?
variation of myosin heavy chain or myosin light chain protein that determines speed of contractions
What does high ATPase activity mean?
faster speed of contractions
How does the amount of contractile proteins influence force?
the larger number of proteins, the larger the force of contraction