Muscle Flashcards
Myomesin and C-protein
Myosin binding protein that aligns thick filaments at M line
Myosin binding protein C
Associated with the M line and important for the assembly and stabilization of the thick filament
Titin
Spring like protein: keeps thick filament centered between 2 of the Z lines of the sarcomere and prevents excessive stretching
Nebulin
Helps anchor thin filaments at Z line and regulates length of thin filaments during development
A-actinin
Actin binding protein that bundles and helps stabilize thin filaments at Z line
Desmin
Surrounds the sarcomere at Z lines attaching them to one another and to the sarcolemma.
Sliding Filament Hypothesis of Huxley
Sarcomere shortens and becomes thicker, but the myofilaments remain the same length:
-Slide past one another
-Increase the amount of overlap
-Sliding action results from repeated “make and break” attachments between the heads of the myosin molecules and neighboring actin filaments
-A band remains constant
-I band and H band both decreases in size
-Z lines are drawn closer to the ends of the A bands
Skeletal muscle fibres are stimulated [ ]
Individually
Skeletal muscle needs [ ] and the loss of input leads to [ ]
nerve input stimulation, atrophy
To Activate skeletal muscles: a certain protein is activated on [ ]
Troponin in thin filaments
Histology of skeletal muscle
Striated
Proteins in skeletal muscle
Actin & Myosin (2 tubules/sarcomere)
Cardiac muscle protein communication through:
Gap junctions
Does cardiac muscle require nerve stimulation to contract?
No: involuntary muscle contraction
Histology of cardiac tissue
Striated
Histology of smooth muscle
not striated, with cells tapered at the ends
Cardiac Muscle Histology
Intercalated Discs
Fascia adherens (adhering junctions)
-Major Structural Element
-Binds cardiac muscle cells at their ends
-Serves as attachment site for thin filaments in terminal sarcomeres
-Transverse component
Maculae adherents (desmosomes)
-Bind individual muscle cells to each other
-Reinforce fascia adherens
-Found in both transverse & lateral component
The delicate of layer of reticular fibers that immediately surrounds individual muscle fibers.
Endomysium
Thicker connective tissue layer that surrounds a group of fibers to forma bundle or fascicle.
Perimysium
Sheath of dense connective tissue that surrounds a collection of fascicles that constitutes the muscle
Epimysium
A band
Marks the extent of the myosin filaments, stays the same length during muscle contraction.
