The seminal vesicles are a pair of elongated saclike glands of the male reproductive system, situated posterior to the urinary bladder, upon the prostate gland and anterior to the rectum. Each seminal vesicle is formed by a highly coiled and convoluted tubule about 15 cm long and surrounded by connected tissue that contains blood, lymphatic vessels as well as nerve fibers. The seminal vesicles secrete sticky fluid that constitutes the bulk of the semen during ejaculation. Sugar fructose and proteins in the secretions of the seminal vesicles provide the indispensable energies, enzymes for traveling through the female reproductive duct to the ovum. Conditions associated with the seminal vesicles tissue contain infections and blockages by inflammation, cysts, or calcification. A pain in the lower left section may indicate the inflammation of the seminal vesicle. A variety of target molecules on the seminal vesicle are used in the detection of related diseases.