Ch 10 Flashcards
Whole skeletal muscle
Epimysium
Surrounds a fasicle
Perimysium
Surrounds individual muscle fibers within muscle fasicle
Endomysium
Less movable bone
Origin
Where bone moves
Insertion
Make up individual muscle cells
Myofibrils
Each myofibril is organized into repeated segments
Basic unit of contraction
Sarcomere
Outer boundaries
Attached to each & extend toward sarcomere are actin
Z line
Make up sarcomere
Actin and myosin
Overlapping actin and myosin
Darker portions of striations
A band
Only thin actin
Lighter region of striations
I band
Only myosin thick, expands from M line
H line
Crosses middle of H zone attachment point for myosin
M line
Smooth ER of muscle cells
Surround each myofibrils
Tubules of SR
End portion of SR
Stores Ca
Terminal cisterns
Deep invaginations of sarcolemma run bw each pair of terminal cisterns
T tubules
T tubule and 2 terminal cisterns
Triad
Each contains an active site for myosin heads to bind
G-actin (globular protein)
2 G-actin strands make up
F-actin (filamentous)
G-actin molecule bind to
Nebulin
Strands cover active sites on G-actin in resting state
Tropomyosin
3 subunits, globular
Bind to tropomyosin, to G-actin, Ca if not resting
Troponin
Muscles shorten
Concentric
Muscles lengthen
Eccentric muscle contraction
Contract slow, fatigue resistant, a lot mitochondria, capillaries, and myoglobin
Red color
Slow oxidative fibers
Contract quick, fatigue quick, force- big muscle, less mitochondria, few capillaries, no myoglobin
Fast glycolytic fibers
Contract quick but not as fast (intermediate), mitochondria, capillaries, and myoglobin
Fast oxidative fibers
