PHGY 209 Lecture Notes - Lecture 16: Myoglobin, Critical Role, Phosphocreatine
15 Apr 2018
School
Department
Course
Professor
Document Summary
The external membrane has the invanginations- the t tubules. The action potential is initated at the end plate but it propagates towards the end of the muscle fiber. It goes into the t tubules and depolarizes them. This activates another channel in the t tubules- voltage gated ca channels. The coupling of the action potential to muscle contractions is resultant of the ca channel (but not the influx of ca). the amount of ca is not enough! The ca channels in the tubules are called dhp receptors: troponin and tropomyosin are attached to the actin filaments. Troponin is a small globular protein and decorated along the length of the thin filament: tropomyosin is a long thing proteins which wraps around the long thing filament. In a resting muscle, the troponin is wrapped around the thin filament that it physically blocks all of the binding sites from the way its wrapped around.
