Endoplasmic and sarcoplasmic reticulum in the heart
Related Experiment Video
Updated: Jun 23, 2026

Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes
Published on: September 18, 2017
1Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada. marek.michalak@ualberta.ca
Abstract:
The concept of the presence of sarcoplasmic reticulum (SR) membrane in the heart is widely accepted and has been considered merely to be a different name for the endoplasmic reticulum (ER) in muscle tissues. Cardiac SR membranes are specialized in the regulation of Ca(2+) transport and control of excitation-contraction coupling. By contrast, the ER is responsible for protein synthesis, modification, secretion, lipid and steroid synthesis, and modulation of Ca(2+) signaling. Recent developments have indicated that functional changes in proteins or pathways normally associated with ER and not SR membrane impact cardiac development and pathology. Here, we propose that the SR and ER might be functionally distinct internal membrane compartments in cardiomyocytes.
Related Concept Videos
Endoplasmic Reticulum
Structure of Cardiac Muscles
Compared to skeletal muscles, cardiac muscle cells are small and mostly have a single nucleus. Additionally, they are usually...
Microscopic Anatomy of Skeletal Muscles
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
Specialized Characteristics of Cardiac Muscles
Cardiac muscle cells are smaller than skeletal muscles, averaging 10–20 mm in diameter and 50–100 mm in length. However, they have large energy demands for continuous contraction and relaxation. This energy is almost exclusively derived from aerobic metabolism of energy reserves in...
Overview of Skeletal Muscle
Smooth Endoplasmic Reticulum
The ER provides optimal conditions for synthesizing steroid hormones and lipids, such as phospholipids and triglycerides. Traditionally, lipid metabolism was considered to be a smooth ER function. However, there is no direct evidence to prove that rough ER is completely excluded from lipid...

