skeletal muscle Flashcards
(18 cards)
what are the 4 primary types of tissue
muscle, nervous, epithelial, connective
what is bone made of and function of the material
calcium for strength
collagen for flexibility
the 3 types of muscle
skeletal, smooth, cardiac
where is smooth muscle found
in hollow organs and tubes (blood vessels)
what are 2 ways of categorising muscle
striated or unstriated
voluntary or involuntary
4 key features of skeletal muscle
multinucleated, large, elongated, cylindrically shaped
what are myofibrils and what are they made of
the contractile elements of fibre made of thick myosin and thin actin filaments
what is a sarcomere
the functional unit of skeletal muscle found between 2 Z lines
the 2 roles of titin
stabilises the thick filaments in relation to the thin filaments
acts as a spring to increase elasticity
where is titin found
extending from the M line to the Z lines
what is the structure of myosin (including heads)
2 polypeptide tails wrapped around each other with globular heads
each globular head has an actin binding site and an ATPase site
what is the function and structure of tropomyosin
thread like molecule that wraps around actin filament, blocking binding sites for myosin cross bridge formation
what is the function and structure of troponin
stabilises tropomyosin, made up on 3 polypeptide units, C/I/T
what is the sarcoplasmic reticulum
fine network of interconnected compartments surrounding each myofibril
where is calcium stored
in the lateral sacks of the sarcoplasmic reticulum
what are T tubules and why are they important
perpendicular extensions of the cell membrane running into the centre of the muscle fibre, they allow action potential to spread down them since they are continuous to surface membrane
series of events that trigger calcium release
- action potential spreads down T tubule
- voltage dependent DHP receptor is activated
- DHP changes confirmation and is connected to ryanodine receptor in the sarcoplasmic reticulum
- ryanodine receptor allows Ca2+ to enter sarcoplasm
what is muscle relaxation dependent upon
calcium reuptake into the sarcoplasmic reticulum
