Test 2 Part 2 Flashcards
CT wrapping of skeletal muscle
endomysium
perimysium
epimysium
thin filament
consist primarily of actin protein - G-Actin monomers that assemble to form a polymer - 2 G-actin polymers twist together to form double stranded helix = filamentous actin (F-actin)
F-Actin + troponin complex + tropomysoin alpha helices
troponins
TnT- attached to tropomyosin in actin groves
TnC - binds Ca ions
TnI - INHIBITS actin myosin interaction; binds troponin complex to actin molecules
tropomyosin
consists of two polypeptide chains that form an alpha-helix. the tropomysoin molecules line up in head to tail arrangement - each tropomyosin molecule rests on 7 G-actin molecules and COVERS their active sites for myosin
thick filaments
consist of myosin II protein about 200 quantity - cool.
myosin components
2 heavy chains (golf clubs)
4 light chains (flat-ish golf clubs)
myosin breakdown with trypsin
2 segments -
1) heavy meromyosin - 4 light, 2 glob heads, short twisted tail
2) light meromyosin - long twisted tail - two chains wrapped around each other in an alpha helix
heavy meromyosin break down with papain
TWO S1 moieties (S1 = 2 light chains +1 glob head) and ONE S2 segment (short twisted tail
organization of muscle
Overlapping of Thin Filaments + Thick Filaments form a –> Sarcomere –> Long cylindrical series of end-to-end sarcomeres form a–> Myofibril –> many parallel myofibrils are enclosed within a –> Muscle Fiber (Muscle Cell)
a-band
dark band - thick and thin fil - widest band
H–band
thick only - bisects a-band
z-line
attachment for thin filaments, contain alpha actinin= anchor, bisects the I-band
m-line
Consists of protein structures lying between thick filaments, holding them in register.
Creatine kinase is the major protein here. Bisects the H-band.
titin molecules
accessory protein - anchors thick fil to the Z-disks - 4 to each thick fil
alpha actinin
accessory protein - anchors thin fil to Z-disk- component of z-disk
nebulin
accessory protein - anchors thin fil to z-disk - 2 nebulins per - NON ELASTIC wrapped around
which three proteins create the orderly arrangement of striated muscle
titin, alpha actinin and nebulin
myomesin
secures thick filaments in register at the M-line.
c-protein
secures thick filaments in register at the M-line. (SAME AS MYOMESIN)
dystropin
cytoplasmic protein that binds actin (thin) filaments to laminin (a component of the external lamina surrounding the muscle fiber).
endomysium
surrounds each msucle fiber/cell - reticular fibers
perimysium
surrounds bundles of many muscle fibers = fascicles - collagenous CT derived from epimmysium
epimysium
many fascicles surrounded by this layer = envelopes the gross muscle - send septa within the muscle so that vessels and nerve fibers may reach deeper aspects of the muscles
transverse tubules (t-tubules)
invaginations of the cell membrane. Their lumen is continuous with the extracellular space, and contain extracellular fluid. Their function is to carry nerve impulses deep into the cell.at junction of A and I band