{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Muscle Physiology 1

Muscle activity must be replenished immediately from

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: troponin FINISH Gating of Sarcoplasmic Reticulum calcium Channels Voltage- gated opening: 2 steps Coupled to T tubules by ryanodine and DHP receptors Calcium- induced opening/closing Conduction of the Action Potential: T tubules are extension of the sarcolemma SR stores Ca2+ via ATP- dependent Ca2+ pump SR has voltage- gated Ca2+ channel Channel response from T tubule depolarization Activates voltage- sensitive DHP receptors DHP = dihydropyridine Activates ryanodine receptors on SR Ca2+ channel As the Ca2+ enters the cytosol, some binds to other voltage dependent SR Ca2+ channels causing them to open as well Ca2+ in cytosol binds to troponin elements Termination of Contraction: Cease input from motor neuron Ca2+ binds low affinity sites to close channels Ca2+ leaves troponin Tropomyosin blocks myosin- actin binding Ca2+ back to the SR by Ca2+ ATPase in SR Transports calcium from cytosol into SR ATP Needs in Muscle: Muscle crossbridge cycle Split ATP by myosin ATPase (power stroke) Bind fresh ATP to myosin (dissociation) Active transport of Ca2+ into SR relaxation Na/K pump maintains he ion gradients, membrane pot...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online