T-tubule
(Redirected from A-I junction)
T-tubule
The T-tubule (or transverse tubule), is a deep invagination of the plasma membrane found in the cardiac muscle cells and skeletal muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell.
Etymology[edit | edit source]
The term "T-tubule" comes from the tubules' unique T-shape. The "T" stands for "transverse," which refers to their orientation in the muscle cell relative to the cell's surface.
Structure[edit | edit source]
T-tubules are formed from the sarcolemma, the cell membrane of a muscle cell. They are oriented perpendicularly to the cell surface, penetrating deep into the cell. The T-tubules are closely associated with the sarcoplasmic reticulum, a specialized form of endoplasmic reticulum, through structures called triads in skeletal muscle and dyads in cardiac muscle.
Function[edit | edit source]
The primary role of T-tubules is to allow for the rapid transmission of the action potential into the cell, which triggers calcium release from the sarcoplasmic reticulum. This calcium release is what initiates muscle contraction.
Clinical significance[edit | edit source]
Alterations in T-tubule structure or function can lead to muscle weakness and disease. For example, in heart failure, the organization of T-tubules can become disrupted, leading to impaired calcium handling and reduced muscle contraction.
See also[edit | edit source]
References[edit | edit source]
T-tubule Resources | |
---|---|
|
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
WikiMD's Wellness Encyclopedia |
Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD