Functional anatomy of the male feline urethra: Morphological and physiological correlations

Anatomical and histological methods were combined with measurements of the urethral pressure profile (UPP) to investigate the functional aspects of th e urethra in male cats. A silicone rubber catheter with two microdiaphragm pressure transducers was used to measure the UPP, Gross anatomy and ultrast ructure of the urethra at each segment were examined and correlated with th e pressure profile data. The preprostatic urethra was composed of three lay ers of smooth muscle, while distal to the prostate striated muscle became p redominant. Increased baseline pressure and rapid fluctuations in pressure in the postprostatic urethra and bulbourethra resulted from the function of periurethral striated musculature. The UPP was affected by the bladder pre ssure, repetition of the measurement, the sensor orientation in the urethra , and the type of measurement catheter. Well controlled high fidelity measu rements enabled a clear correlation to be established between the features of the UPP and the anatomy of the urethra and surrounding musculature. Addi tionally, observations on the ultrastructural and microscopic anatomy of th e urethra extend a previous description of the pelvic urethra.