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[Histochemical study of human external urethral sphincter]
K Okamura1, S Tokunaka, S Yachiku
1Department of Urology, Asahikawa Medical College.
Nihon Hinyokika Gakkai Zasshi. the Japanese Journal of Urology
|September 1, 1991
Summary
Human external urethral sphincter muscle shows significant variation in fiber type proportions and diameter. Differences in muscle fiber size between sexes suggest potential sexual dimorphism in this crucial muscle.
Area of Science:
- Histochemistry and muscle physiology.
- Analysis of human skeletal muscle tissue.
Context:
- The human external urethral sphincter plays a vital role in urinary continence.
- Understanding the structural characteristics of this muscle is essential for clinical applications.
Purpose:
- To investigate the histochemical composition and fiber type characteristics of the human external urethral sphincter.
- To identify potential variations in muscle fiber types and their diameters among individuals and between sexes.
Summary:
- Histochemical analysis (ATP-ase staining) of 13 human external urethral sphincters revealed significant interindividual variation in muscle fiber type proportions.
- Type 2 muscle fibers were significantly larger in diameter than type 1 fibers across most cases.
- While no correlation was found between fiber type percentage and age or sex, distinct patterns in fiber diameter emerged between male and female subjects, suggesting sexual dimorphism.
Impact:
- Highlights extreme interindividual variability in external urethral sphincter muscle composition.
- Provides evidence for potential sex-based differences in the structure of the external urethral sphincter muscle.
- Informs future research on urethral sphincter function, dysfunction, and potential therapeutic interventions.