Skeletal Muscle Flashcards
What causes muscle contraction?
interactions between actin microfilaments and bipolar myosin filaments
are the skeletal muscles attached to our bones are under voluntary or involuntary control?
voluntary
What are the 3 types of muscle tissues?
cardiac
skeletal
smooth
what does contraction of the 3 muscle types depend on?
ATP-driven sliding of actin against myosin
T or F: skeletal muscles are small with similar organization to other muscle cells
FALSE, they are LARGE and UNIQUELY organized
How many nuclei does a single skeletal muscle cell contain?
hundreds
Why does a single skeletal cell contain so many nuclei?
they are formed by the fusion of many pre-muscle cells in the embryo
How thick are skeletal muscles?
10-100 um
How long are skeletal muscles?
can be hundreds of mm in length
What fills up most of a skeletal muscle cell?
mostly cytoskeleton arrays, some cytoplasm
T or F: skeletal muscle cells are mostly composed of cytoplasm
false! mostly cytoskeleton arrays
Briefly describe the structure of skeletal muscles
a single cell contains hundreds of nuclei
is very thin (10-100 um)
is very long (hundreds of mm)
contains very little cytoplasm - mostly cytoskeleton arrays
What is a fascicle?
a bundle of muscle cells
What is a muscle fibre?
an individual muscle cell
What is a bundle of muscle fibres called?
a fascicle
What surrounds a single muscle fascicle?
a connective tissue sheath
What is a bunch of sheath-coated fascicles called?
skeletal muscle tissue
What are myofibrils?
long cylindrical strands inside every muscle cell/fibre
What are myofibrils mostly composed of?
cytoskeleton components (long stretches of actin and myosin)
What does a bunch of myofibrils make?
a single muscle fibre
What does the prefix ‘sarco’ imply?
the component is part of a muscle cell
What is the sarcolemma?
the plasma membrane of skeletal muscle fibres/cells
What is the sarcoplasm?
the cytoplasm of skeletal muscle fibres/cells
What is the sarcoplasmic reticulum?
the smooth endoplasmic reticulum of the muscle cells