Skeletal Muscle Flashcards
Black arrows?
Type I fibers
What is alpha actinin
protein that attaches thin filaments to the Z-line
Blue arrows?
Type II fibers
Arrows?
Myocyte nuclei
What is alpha-beta crystallin?
a heat shock protein that protects desmin from mechanical stress.
What is nebulin?
A molecule that lies on top of actin filaments in the sarcomere. It regulates the length of an actin filament.
Identify
Cardiac muscle, Acute MI
What are satellite cells?
Cells that attach to myotubes before the basal lamina is laid down. They function as stem cells and give rise to myogenic precursor cells (replaces damaged muscle).
What is the dystroglycan complex?
It links dystrophin (intracellular) to laminin-2 (extracellular).
smooth muscle
Smooth muscle
What is type I myofiber also known as?
red/dark fibers
skeletal muscle
What are the 3 types of muscle tissue?
smooth, skeletal and cardiac
Smooth muscle
What is speed of contraction of type I myofibers?
slow and continuous
What is one way that smooth muscle and skeletal muscle differ?
Smooth muscle has single mononucleated cells and skeletal muscle has many cells.
Why are type IIB myofibers light?
They have little to no myoglobin; type IIA uses ANAEROBIC respiration.
Blue arrows?
Type II fibers
Identify
Muscle spindle
Why is type I myofiber dark?
due to the large armount of hemoglobin in the fibers; type I myofibers use OXIDATIVE PHOSPHORLYATION. They also have high ATP, and NADH
What are the components of a neuromusclar spindle?
extrafusal fibers, intrafusal fibers, alpha motor neurons, gamma motor fibers, primary and secondary afferent fibers.
If NAD stain is dark in myofibers, what does that indicate?
The myofiber is high NAD, and hence uses oxidative phosphorylation. It is probably at type 1 myofiber.
what are two features of cardiac muscle visible in a picture?
intercalated discs and sarcomeric arrangement.
Identify
Cardiac muscle
What are type IIB myofibers also known as?
white/light fibers
C?
Myofibril
How do the contraction of type IIA myofibers compare to type I and IIB contractions?
Type IIA contracts faster than type I, but slower than type IIA.
Black arrows?
Type I fibers
What is type IIA myofiber also known as?
intermediate fibers
What are the gap junctions called that are found in cardiac muscle?
intercalated discs.
What is titin?
A molecule that extends from the Z disc to the end line. It maintains the position of the myosin filaments in the sarcomere.
Arrowhead?
Satellite cell
A?
Fascicle
What is the contraction mechanism of skeletal muscle?
all or none
Identify
muscle spindle
What is dystrophin?
A molecule that links alpha-actin/desmin to the cytoplasmic side of the sarcolemm and anchors actin to it as well. It also reinforces sarcolemma during muscle contraction.
Skeletal Muscle
Cardiac Muscle
E?
Epimysium
B?
Myofiber
Do type IIB myofibers fatigue quickly or slowly?
slowly
What are the similarities between smooth and cardiac muscle?
Both use gap junctions, do not conduct an “all or nothing” signal and are not directly innervated.
G?
Perimysium
D?
Endomysium
F?
Blood vessels
What kind of respiration does type IIA myofiber use?
BOTH aerobic and anaerobic resiration.
How are skeletal muscle cells formed?
When individual myoblasts form a myotube.
