Muscle Tissue/ muscle cell/sacromere (UNIT 4)
Troponin
Attached to tropomyosin, binds Ca2+ (muscle contraction)
Skeletal
Attaches to bone, voluntary, striated, multinucleated
Titin
'Tightens'/ connects to z lines(thin filament) on each end of sarcomere SPANS MYOSIN
m line
'middle', connect thick to thick filament
Contractile/myofilaments
'strands' directly involved in contraction
A bands
Everywhere there is thick filament/myosin
Cardiac
HEART, involuntary, striated, intercalated discs(gap junctions)
sarcoplasmic reticulum
High in Ca2+; covers myofibril
Nebulin
Holds actin strand together, makes up length of actin but actin will stay the same length SPANS ACTIN
Smooth
Lining of blood vessels/digestive tract/ respiratory tract, bladder, unstriated, single nuclei, tapered at ends, PASSAGEWAY TO MANY SYSTEMS
Myosin
Thick filaments, site for hydrolysis and actin binding site MOTOR
Actin
Thin filaments, subunits of g - actin, active sites for myosin binding
Structural protein
anchor and regulate length of myofilaments, alignment for optimal contraction
Myofibrils
contain sarcomeres
Tropomyosin
covers the active sites on g - actin molecules (blocks myosin binding sites, prevents cross-bridge formation)
Sarcoplasm
cytoplasm of a muscle fiber Contains: glycogen(sugar), myoglobin(stored oxygen)
z discs
end of sacromere, zig zags
Regulatory protein
found on actin
Multinucleated
more than one nucleus per cell
Zone of overlap
overlapping of myosin and actin
Transverse (T) tubules/triad
small tubes run across muscle fiber and allow things on sarcolemma to enter *Are located at zone of overlap
Sarcomeres
smalllest unit of contraction, formed by regulatory, contractile, and structural proteins
Endomysium
surrounds each fasicle
Epimysium
surrounds entire muscle
Perimysium
surrounds fascicles
Sarcolemma
surrounds outside of entire muscle fiber
h zone
thick filament/myosin ONLY
I bands
thin filament/actin ONLY
Dystrophin
transfers force of myofilament movement to sarcolemma and extracellular connective tissues
Terminal cisternae
Store Ca2+ and release when there is an AP
