The urethra

The urethra is a tube which conveys urine caudally from the bladder through the pelvic cavity to the out­side. Its structure varies according to the sex of the animal, and in the case of the male animal, between cats and dogs.

Temale-Ihe urethra is a short tube, opening into the floor of the reproductive tract at the junction of the vagina and vestibule. The opening is know^rn as the CXteriuiI Iirethnil orifice and is located in the centre of a small ridge, the urethral tubercle. This is a useful landmark when Catheterising a bitch and can be seen w^rhen using a speculum.

Male - the urethra is divided into two parts: the pelvic urethra and the penile urethra. There is a difference between the dog and the tomcat:

- I)θf∣ (see Ch. I 1. Eig I 1.1). Close to the neck of the bladder, there are three openings into the urethra - one of these is from the prostate t∣land and two are from the deferent ducts or ∖^,as deferens (one from each testis). The urethra runs caudally through the pelvic cavity, over the edge of the ischial arch where it is joined by erectile tissue to form the penis. The penile urethra opens to the outside at the tip of the penis.

- Tomcat (sec Ch. 11. Eig. 11.2). There is a short length of urethra, cranial to the openings from the prostate gland and the deferent ducts, know n