Table 2.
Species | Sex | Histologic studies | Functional studies | References |
---|---|---|---|---|
Rat | Female | Striated muscle is thin and circular, prominently occupying the middle urethra. Type II fibers are predominant. |
Urine flow disrupted by partial/full closure of urethra Lower max flow rate and shorter micturition time |
Praud et al. [51] Lim et al. [52] Buffini et al. [56] Biérinx et al. [53] Streng et al. [59] |
Male | Striated muscle forms a thick layer. 100% type II fibers in the upper urethra. Luminal muscle contains a mix of type I and II fibers. |
|||
Human | Female | Striated muscle extends the length of the urethra and is composed of predominantly type I slow twitch fibers (87% vs. 13%). | Benoit et al. [60] Ho et al. [62] |
|
Male | Striated muscle extends from the membranous urethra over the prostate and has a mixture of both slow and fast twitch fibers (65% vs. 35%). |