Which male reproductive structure secretes a thick, viscous fluid that contributes to semen?

The seminal vesicle is responsible for secreting a thick, viscous fluid that plays a critical role in the composition of semen. This fluid contains nutrients, such as fructose, which provide energy for sperm, as well as prostaglandins that help with the motility and viability of the sperm upon ejaculation. This secretion makes up a significant portion of the total volume of semen and enhances the chances of successful fertilization.

Understanding the function of the seminal vesicle is essential in the context of male reproductive health. The fluids produced by this structure work in conjunction with secretions from other glands, such as the prostate gland and bulbourethral glands, to create an optimal environment for sperm transport and survival.