Seminal vesicles are two lobulated lying on the posterior surface of the urinary bladder. Structurally, it is composed of a highly coiled tube embedded in connective tissue. Each is about 2 inches long and is separated from the other by the terminal part of vas deferens, which lies to its medial side. Posterior to the seminal vesicles lies the rectum.
Towards the inferior side, each seminal vesicle narrows down and joins the terminal part of vas deferens of the same side to form the ejaculatory duct.
The arterial supply is provided by the inferior vesicle and middle rectal arteries. Venous drainage is by way of small veins that drain into the internal iliac veins.
Lymph from the seminal vesicles is drained to the internal iliac nodes.
Seminal vesicles are secretory in function. They produce a secretion that is added to the seminal fluid. Specifically, the secretion of seminal vesicles is concerned with nourishment of spermatozoa. During the process of ejaculation, the seminal vesicles contract and pour their secretion into the ejaculatory ducts, and therefor also wash-down the spermatozoa out of urethra.