Skeletal Muscle and Structure Flashcards
skeletal muscle is just one of the 3 types of muscle in body. what are the others
cardiac muscle
smooth muscle
skeletal muscle
which muscle types are striated (stripy appearance)
cardiac muscle
skeletal muscle - striated due to alternation of thick and thin filaments
skeletal muscle is always attached to..
a tendon- because it causes movement
name of the outer connective tissue layer around the skeletal muscle
epimysium (outer layer)
what is the muscle fascicile
structure where the muscle cells are in a bundle
what is the connective tissue layer around the muscle fascicle
perimysium
what is the name of layer around each muscle fibre/ cell
endomysium (inner layer)
skeletal muscle fibres are highly vascularised due to which blood vessel
capillaries that form a network
skeletal muscles are multi-nucleated. where are the nuclei positioned
on peripheries/ outer part
there is 1 nucleus every ____ sarcomeres
every 15 sarcomeres
why are muscle fibres multi-nucleated
proliferating myoblasts fuse into muscle fibres multiple times
what are satellite cells
cells for growth and regeneration
they divide into more proliferating myoblasts to repair skeletal muscle and more satellite cells
where are satellite cells found
under the base of lamina
90% of the skeletal muscle is myofibrils. what are myofibrils
longitudinal contractile cell unit composed of sarcomeres arranged in series
what is a length of full sarcomere indicated by
one z-disk to another z-disk= 1 sarcomere
A band contains
actin and myosin overlap
I band contains
actin only
the z-disk runs …
through the middle of the I-band
what is the H zone
only myosin- no actin
where is the H-zone
a darker band in the centre of the A band
what happens to the I band during muscle contraction
width of I band decreases
what happens to the A band during muscle contraction
stays the same
what happens during muscle contraction
the filaments SLIDE PAST each other
what is a myosin crossbridge
projections from the thick filament
- 6 thin surround 1 thick filament
what is thick filament
myosin
what is thin filament
actin