A 5 Muscle Flashcards
Where do you find intercalated disks?
cardiac muscle only.
which types of muscles have branched fibers?
cardiac
which type of muscle has a largest diameter? smallest?
largest = skeletal middle = cardiac smallest = smooth
which types of muscles are striated?
skeletal and cardiac only
what is the epimysium?
covers entire muscle
what is the perimysium?
covers fascicles
what is the endomysium?
covers muscle fibers.
what is the order of muscle from largest to smallest?
muscles, fascicle, muscle fiber, fibril, sarcomere.
How would you describe skeletal muscle?
voluntary
multinucleated
striated
which cells repair damaged skeletal muscle?
satellite cells
I band
only thin filaments (actin)
z line
where thin filament attaches (also alpha actinin)
A band
the entire length of the thick (myosin) filament
H zone
the area with only myosin. centered on the m line.
M line
the mysosin attachment site
sarcomere
z line to z line
How would you describe cardiac muscle?
involuntary, 1-2 nuclei, intercalated disks, striated, many mitochondria, a lot of glycogen.
Which three things are found in all intercalated disks?
desmosomes, gap junctions, and fascia adherins.
How would you describe smooth muscle?
involuntary, no striations, thick/thin filaments with dense bodies, a lot of mitochondria, a lot of elastin, collagen, and proteoglycans because smooth muscle can make these three.
what is tropomyosin?
a band of protein that covers up the actin binding sites.
what is troponin?
it sits on tropomysosin and acts as a receptor to displace tropomyosin when calcium binds it.
what is nebulin?
an actin binding protein that regulates actins length during sarcomre assembly.
what is alpha actinin?
dense bodies ( smooth muscle) = z line (in skeletal muscle)
help to anchor the actin filaments to the z line or dense body
what is tropomodulin?
a protein that binds the caps of the negative ends of actin preventing the spontaneous dissociation of the actin polymer.
what is titin?
it connects the z line to the m line in striated muscles only, and also acts as a molecular spring.
during the contraction of muscle, what happens when atp binds to myosin?
the mysoin head can be released from actin.
what is rigor mortis?
when the myosin is stuck to actin because there is no atp to release it.
when calcuim enters to muscle to promote contraction, what is bound to the myosin?
ADP + Pi
what causes the power stroke to occur?
the release of Pi
what causes the ADP to fall off of myosin during muscle contraction?
The addition of another ATP.
what does creatine kinase do?
Allows for ATP +Cr —-> ADP + PCr
what is the optimal length of a sarcome to generate the maximum contraction?
about 2.3 micormeters.
what is the golgi tendon organ?
Its an inhibitory signal that prevents over stretching/contraction of a muscle.
what is calmodulin?
A calcium binding protein in smooth muscle. Recall its analog in skeletal muscle would be troponin.
