1981 Volume 72 Issue 3 Pages 306-312
A new technique was employed for visual observation of the contraction of the urinary bladder and urethra. This technique enabled us to observe directly the urinary bladder, prostate and urethra after resecting pubic bone concealing the urinary bladder neck, prostate and proximal urethra of the male dog.
Using this preparation, we understood that the urethral contraction was closely connected with the contraction of the rectum and anus. In addition, we observed two different contraction of the urethral striated muscle. One was the circular contracion of so-called external urethral sphincter positioned below the prostate. The other was the longitudinal contraction of the periurethral striated muscle. And the latter was stronger than the former. It was likely that the bladder contraction was started and then the bladder neck was tracted to the upper oblique direction mechanically when the pelvic nerve was electrically stimulated. As the result of the bladder contraction, we thought that the bladder neck opened not nervously but mechanically. We observed that the bladder neck was fastened when the hypogastric nerve was stimulated electrically. Although the contraction of the urethra was not observed then.
Our technique served the purpose of examining electrophysiologically the lower urinary system, observing its dynamic contraction simultaneously.
