muskuloskeletal Flashcards
sliding filament theory steps
1)an AP crosses the NMJ
2) Ca2+ channels open ( released from the SR
3) Ca2+ unlocks tropomyosin exposing ht emyosin head binding sites
4) ATP binds to the myosin heads –> ADP +P “ COCK & BIND)
-power stroke occurs
*requires more ATP to do again
what are the 3 types of muscle tissue?
cardiac: involuntary, has intercalated discs and 2 nuclei, striations
Smooth: involuntary, no striations (organs)
skeletal: multinucleate, striations, alpha motor neurons
Epimysium?
surrounds the entire skeletal muscle
Perimysium?
surrounds muscle fassicle
endomysium?
surrounds muscle fiber
muscle fiber
muscle cell
sarcolemma
plasma membrane
end plate
where the alpha motor neuron connects w the muscle fiber
SR?
the ER of the muscle ccell, a lot of Ca2+, and VG Ca2+, & transports for Ca2+
T-tubules
extension of the sarcolemma
sarcomere
contractile unit of the muscle cell made up of myofilaments ( striated appearance)
what do I -bands poses at rest only?
actin
what do A-bands poses at rest?
myosin & actin
z-discs?
end of the sarcmere ( attment points for the atin filaments.
H-zone only has __ at rest?
myosin
myofilaments?
actin: thin filament, F-fibrous(2 chains) G-globular= winds together= helix
myosin: thick filament heads bind to actin, heads appear every 60 degrees need Ca2+ to bind
myofilament associate proteins
tropomyosin: winds around f-actin and blocks troponin (bind sites)
troponin: has 3 binds sites
-C-Ca2+
A-Actin
T-tropomyosin
what are some skeletal muscle properties?
excitable, elastic, extensible, contractable
functions:
movement, joint stability, organ system, protection, thermoregulation
NMJ
chemical synapes between alpha motor neuron and the motor end plate of the muscular fiber
small motor unit
alpha motor neuron innervates onle a few fibers
- more fine control, small representation in the primary otor cortex
motor end plate has lots of____ channels
ioniotropic nicotinic ACH receptors ( LG Na+)
what is the RMP?
-90mv
excitation contraction coupling
ap—> neuron terminal—> Ca2+ channels open—-> ACH binds ot NaChR on motor end-plate, Na+ enters muscle cell=graded potential–> muslce Ap—> K+ in to repo