Triad (anatomy)
Triad (anatomy) refers to a specific arrangement of structures within various parts of the body, particularly noted in the context of muscle physiology and neuroanatomy. The term "triad" in anatomy typically describes a group of three closely related components or structures that work together to perform a specific function. One of the most well-known examples of a triad is found in the skeletal muscle cells, where it plays a crucial role in muscle contraction.
Structure and Function[edit | edit source]
In the realm of muscle physiology, the triad is a specialized arrangement found in the skeletal muscle fibers. It consists of two terminal cisternae of the sarcoplasmic reticulum (SR) and one T-tubule. The T-tubule is located between the two cisternae, forming a tripartite structure. This configuration is essential for the process of excitation-contraction coupling, which is the mechanism by which a muscle fiber contracts.
The T-tubules, extensions of the cell membrane (sarcolemma), penetrate into the cell's interior and bring action potentials (electrical signals) deep into the muscle fiber. The sarcoplasmic reticulum, which stores calcium ions, releases these ions into the cytoplasm when the muscle cell is stimulated. The released calcium binds to troponin, initiating the contraction process by allowing the myosin heads to bind to actin filaments.
Clinical Significance[edit | edit source]
Alterations or dysfunctions in the components of the triad can lead to muscle weakness or diseases. For example, mutations affecting the ryanodine receptor, a calcium release channel on the sarcoplasmic reticulum, can result in malignant hyperthermia, a severe reaction to certain anesthetics, or various forms of congenital myopathies.
Other Examples[edit | edit source]
While the triad in skeletal muscle fibers is the most commonly discussed, the term can also refer to other sets of three structures in different parts of the body, each with its specific relevance to the function or pathology of that region. However, the skeletal muscle triad remains the most studied and significant in terms of its physiological role.
See Also[edit | edit source]
 | This medical article is a stub. You can help WikiMD by expanding it. |
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
