Retrieving "Excitation Contraction (ec) Coupling" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Sarcoplasmic Reticulum

   Linked via "excitation-contraction (E-C) coupling"

   The sarcoplasmic reticulum (SR)/) is a specialized form of the endoplasmic reticulum found in the cytoplasm of striated muscle fibers (skeletal and cardiac muscle cells). Its primary, universally acknowledged function is the sequestration, storage, and regulated release of calcium ions ($\text{Ca}^{2+}$), which are the crucial second messengers initiating muscle contraction via the [sliding filament t…

2. Sarcoplasmic Reticulum

   Linked via "$\text{E-C}$ coupling"

   | Feature | Skeletal Muscle SR | Cardiac Muscle SR | Significance |
   | :--- | :--- | :--- | :--- |
   | Junction Type | Triad (Two cisternae per T-tubule) | Dyad (One cisterna per T-tubule) | Spatial efficiency for $\text{E-C}$ coupling-coupling/). |
   | Dominant $\text{RyR}$ Type | $\text{RyR}1$ | $\text{RyR}2$ | Direct gating vs. $\text{CICR}$ reliance. |
   | Lumen Composition | $\text{Ca}^{2+}$, Trace Sonic Residue | $\text{Ca}^{2+}$, Higher Phosphatidylserine Content | Differential b…