what microfilaments are in muscle that allow it to contract
actin and myosin
what's muscle tissue's main function
contraction to produce organized movement
what is cells specialized for muscle tissue
myocytes (muscle fibers or myofibers)
what is the sarcoplasm
it is the cytoplasm in muscle tissue
what is cytoplasm called in muscle tissue
sarcoplasm
how does muscle tissue present (staining) and why
eosinophilic (pink) because of myofilaments
what is the name of the ER in muslce tissue
sarcoplasmic reticulum
types of muscles (3)
skeletal
cardiac
smooth
from big to small, list the how skeletal muscle is structured
myofiber (muscle fiber)
myofibrils
myofilaments (actin and myosin)
cell range width and length of skeletal muslce cells
width 10-110um
length up to 50 cm
what do myofibers derived from
prenatal fusion of many mononuclear myoblasts
where are the nuclei located in skeletal muscle
peripheraly
what are myofibrils composed of
think and thin myofilaments
what does the thick filaments composed of
myosin
what does the thin filiments composed of (3)
actin
troponin
tropomyosin
the A band consists of
thick and thin myofilaments overlap
the I band consists of
thin myofilaments
what is responsible for the striations in muscles
the alternating light and dark bands
where is the Z line located
it bissects the I bands
where is the H band
the myosin filament inside the A band where the is no overlap of myosin and actin
where is the M line
it bisects the H and A band
what does the sarcoplasm contain (4)
sER (sarcoplasmic reticulum)
glycogen
mitochondria
myoglobin
what covers a muscle
epimysium
what covers a muscle bundles
perimysium
what covers muscle fibers
endomysium
what is the order of compartmentalizing in skeletal muscle starting from largest to smallest
epimysium (muscle)
perimysium (muscle bundle)
endomysium (muscle fiber)
what are satellite cells (3)
spindle-shaped cells with heterochromatic nuclei
located adjacent to myocytes
inactive myoblats that can be activated when injury happens in muscle fiber to regen.
what are red and white muscle fibers (2)
The red (slow-twitch) fibers are smaller, rich in myoglobin and mitochondria
white (fast-twitch) fibers are larger with few mitochondria.
what type of muscle is great at healing
smooth muscle
what's the structure of cardiac muscle(4)
myocytes (fibers) branch and anastomose
single nucleus located center of cell
sarcoplasm is acidophilic
cells are connected by intercalated discs
what are intercalated discs
present as dark lines in cardiac muscle, they are intercommunication junctions
what do intercalated discs create between cells (2)
syncitium
link adjacent cells mechanically and electrically
what can skeletal and smooth muscles do that cardiac muscle can not do
regenerate/repair any such repair leaves a myocardial scare
each cardiac muscle fiber is surrounded by what
network of fine reticular and collagenous fibers
what are purkinje fibers
specialized impulse conducting fibers having a centrally located nucleus surrounded by granular (rich in glycogen) sarcoplasm they are less red and myofibrils are located in the periphery
what is the "pace maker" fibers in the cardiac muscle
purkinje fibers
structure of smooth muscle
elongated, spindle-shape with a single centrally located nucleus (elongated) and an acidophilic cytoplasm
what holds smooth muscle cells together
a fine network of reticular fibers made by myocytes not fibroblasts
unlike cardiac and skeletal muscle, smooth muscles actin and myosin are different in what ways (2)
more thin myofilaments then thick
thin myofilaments only have actin and tropomyosin and no troponin
less organized (not striated)
what serves as anchor sites for in smooth muscles for its myofilaments
dense bodies in the cytoplasm and cell membrane
what further links the dense bodies into a meshwork array in smooth muscles
intermediate filaments
what do the numerous vesicles along the cell membrane in smooth muscles do