chapter 10- muscle tissue Flashcards
(22 cards)
muscles make up _____ of body mass
almost half
muscles transfer ATP to
directed mechanical energy
functions of muscle tissue
movement and maintaining posture
4 main characteristics
excitability, contractibility, extensibility, elasticity
nerve endings are found
in every muscle cell
muscle tissue is vascularized for
nutrients, oxygen, energy, and waste removal
epimysiym
dense irregular connective tissue that surrounds whole tissue
perimysium
dense regular connective tissue that surrounds bundles of muscle fiber
endomysium
areolar loose connective tissue that surrounds each muscle fiber
cell characteristics
large multinucleate cells
sarcolemma
plasma membrane of muscle cells
sarcoplasm
cytoplasm of muscle cells
sarcoplasmic reticulum
smooth ER around myofibrils that store regulate and release calcium
Z line
anchor for actin
M line
anchor for myosin
sarcomere
functional unit of skeletal muscle, z disc to z disc
myofilament types
myosin and actin
myosin
thick, rodlike tail with 2 heads that are binding sites for actin and ATP
actin
thin, binding site for myosin heads, made of G-actin string (2 twisting strands)
tropomyosin
rod like structure that wraps around actin and blocks it from myosin binding
troposin
3 polypeptide subunit complex in actin- 1 bound to actin, 1 bound to tropomyosin, 1 bound to calcium
steps of sliding filament of contraction
- myosin binds to actin, forms crossbridge
- myosin pulls actin, power stroke
- ATP binds to myosin
- myosin can detach from actin after ATP binding, then returns to cocked position for next power stroke
