Muscle Q

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Muscle Q

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paba
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Topics: 15
Posts: 57

04/19/06 - 02:18 PM

An experiment is conducted in which a skeletal muscle is initiated using an electrical stimulator.which of the following mechanisms best explains why a skeletal muscle twitch thus initiated will come to an end?

A.active return of Ca to the Sarcoplasmic reticulum
B.Ca release channels(ryanodine receptors)
C.Dihydropyridine receptors
D.Muscle ATP stores-exhausted
E.Sarcoplasmic reticulum is depleted of Ca
F.Transverse tubules close

doc179
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04/19/06 - 03:04 PM

star1
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04/19/06 - 10:07 PM

r_albayunen
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04/19/06 - 10:19 PM

withdrawal of calcium? a?

paba
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04/20/06 - 05:09 AM

(any expln, Please)

doc179
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04/20/06 - 10:39 AM

when the muscle is depolarised the dihydropyridine open the ryanodine channels which are on the sarcoplasmic reticulum near the T tubules and calcium is released. calcium will bind to the troponin and tropomyosin will move to expose the binding sites for myosin on actin. and the muscle contracts. but for myosin to interact with actin the ATP on it should be hydrolysed. and when the ATP reattaches to the myosin head and the calcium is actively transported into the sarcoplasmic reticulum the contraction ends.

paba
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04/21/06 - 06:11 AM

thanks,doc179

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