Muscle and Vessel VHA Flashcards
what is the only voluntary muscle?
skeletal muscle
what are 2 defining features of skeletal muscle?
striated
peripheral nuclei
Zoom in on a muscle cell fibers
muscle cell -> fascicles -> myofibrils -> myofilaments (actin and myosin)
what do T-tubules allow for?
simultaneous contraction
What connects to the Z-disc?
actin filaments
What region does not change during contraction? What does this region contain?
A-band
A-band contains both thin (actin) and thick (myosin) filaments
A-band is innermost region of sarcomere
I band
space between the A-band and Z-disc that contains mostly actin
Sarcomere
spans from Z-disc to Z-disc
contracts
Which band causes striations on H+E stain?
A-band
What are the dots on low power electron micrograph of muscle?
mitochondria
4 key features of cardiac muscle
branching fibers
striated
centrally located nuclei
intercalated discs
intercalated discs
connect cardiomyocytes
Lf pigment
yellow dots in cardiac muscle
sign of aging
What are intercalated discs composed of?
adherens junction, desmosomes and gap junctions
intercalated discs are intercellular junctions that link cells
Signs of MI in cardiomyocytes
eosinophilic
lympocytes and macrophages
pyknotic nuclei
pyknotic nuclei
irreversible condensation of chromatin seen in necrosis / apoptosis
2 defining features of smooth muscle
centrally located nuclei
non-striated
what is the shortest muscle type?
smooth muscle
does smooth muscle have sarcomeres / striations?
no!
what does contraction look like in smooth muscle?
twisting and contortion of cell + nuclei
Which cell type is collagen normally present with? How do we stain it?
smooth muscle
collagen stains blue with trichome
3 blood vessel tunics
tunica intima (up against blood, intermost)
tunica media
tunica adventitia
tunica intima is comprised of …
endothelial tissue and sub-endothelial connective tissue
tunica media is comprised of …
mostly smooth muscle
