Seminal Vesicles – Tutorial
Please read Unit 12 – Introduction to Male Reproductive System Tissues prior to completing the activities in this chapter.
Introduction to the Seminal Vesicles
The seminal vesicles (seminal glands) are a pair of tubular glands folded into a compact mass approximately 2 inches (5 cm) in length located against the posterior wall of the urinary bladder just lateral to the ampullae of the vas deferens. The outer wall of the seminal vesicles is comprised of a thick layer of smooth muscle. Internally, the seminal vesicles have many short side branches with extensive folds known as secretory pockets lined with pseudostratified columnar epithelium.
The secretory pockets of the seminal vesicles secrete seminal fluid which is ejected into the ejaculatory duct by peristatic contractions of smooth muscle in the wall of the gland during ejaculation. Seminal fluid then combines with sperm from the vas deferens in the ejaculatory duct and together are discharged into the urethra where they mix with other fluids to create a mixture known as semen which is discharged from the urethra during ejaculation. Seminal fluid accounts for most of the semen volume (approximately 60%) and contains a mixture of fructose which can be metabolized by swimming sperm as an energy source, fibrinogen which forms a semen clot shortly after ejaculation, and prostaglandins that stimulate contraction of smooth muscle along the male and female reproductive tracts. Seminal fluid also has a slightly alkaline (basic) pH which helps neutralize the acidic pH within the vagina during intercourse.
Tutorial: Use the image slider below to learn more about the structure and characteristics of the seminal vesicles.
Microscopy: Use the image slider below to learn how to use a microscope to study seminal vesicles on a microscope slide.
