Lecture 3 - Muscular Tissue Flashcards
what are the major divisions of muscle tissue, in descending order?
muscle -> fascicles -> muscle fibers -> myofibrils -> myofilaments
def: surrounds a muscle and is continuous with fascia and the tendon binding muscle to bone
epimysium
def: surrounds fascicles
perimysium
def: surrounds muscle fibres, connective tissue that rests on a basement membrane
endomysium
def: cells that lie deep to the endomysium but superficial to the sarcolemma
satellite cells
________ constitute about 80% of myocyte volume
myofibrils
how can you identify different myofibrils in longitudinal section?
they are slightly out of alignment of each other
def: includes both thick and thin filaments, consists of contractile protein arrays bundled within myofibrils
myofilaments
def: contains 200-500 molecules of myosin
thick filament
def: contains F-actin, tropomyosin, and troponin
thin filament
def: dark overlapping region of thick and thin filaments
A bands
def: area with no filament overlap, thick filaments only, no cross bridges
H zone
def: light thin filaments plus titin
I bands
def: dark, mark the ends of the sarcomere and anchor thin filaments
Z bands
def: connects the Z band to the M line
titin
irrespective of the degree of contraction of the muscle fibre, the ______ ______ remains constant in width, while the __ and __ bands narrow in contraction to pull the ____ lines closer together
A band, I and H bands, Z lines
def: thick filaments with fine interconnections
M line
def: slow, red oxidative fibres, many mitochondria, abundant myoglobin, derive energy from aerobic oxidative phosphorylation of fatty acids, adapted for slow contractions over prolonged periods, small in transverse
Type I
def: fast, intermediate oxidative-glycolytic fibres, derive energy from aerobic oxidative phosphorylation of fatty acids and anaerobic glycolysis, adapted for rapid contractions and short bursts of activity, large transverse section
Type IIa
def: fast, white glycolytic fibres, relatively few mitochondria, less myoglobin, derive energy mostly from anaerobic glycolysis, rapid contractions and fatigue very quickly, large in transverse
Type IIb
how is MHC I expressed in IHC?
in green
how is MHC IIa expressed in IHC?
red
what kind of training induces a more oxidative quadriceps muscle phenotype?
endurance training
cardiac muscles are branched and joined end to end and side to side by ________________ ________-
intercalated disks
where are nuclei in cardiac muscle located?
centered
def: modified cardiac myocytes, scattered along the inner part of the myocardium adjacent to the endocardium
purkinje fibers
purkinje are ______ and contain ________ stores
large and contain glycogen
do smooth muscle fibers have sarcomeres?
no
