Transverse tubule system
Network of membrane invaginations in cardiac myocytes that facilitate calcium release and excitation-contraction coupling.
Full Definition
The transverse tubule system (T-tubule system) consists of specialized membrane invaginations that extend from the sarcolemma deep into cardiac myocytes, forming a complex network that enables rapid and uniform calcium release throughout the cell. These tubules align with the Z-lines of sarcomeres and are in close proximity to the sarcoplasmic reticulum, forming calcium release units essential for excitation-contraction coupling. In cardiac pathology, alterations to the T-tubule system can occur in various cardiomyopathies, heart failure, and metabolic disorders. Loss or remodeling of T-tubules can impair calcium handling and contribute to contractile dysfunction. Ultrastructural examination by electron microscopy is often required to assess T-tubule morphology and organization.
Usage
Usage note: May be abbreviated as 'T-tubule system' after first use. Distinguish from sarcoplasmic reticulum in functional descriptions.
In Context
- "Electron microscopy revealed disruption of the transverse tubule system in the failing myocardium." — Ultrastructural pathology report
- "The transverse tubule system showed normal organization in the control cardiac tissue samples." — Research cardiac biopsy analysis