What structure contracts to aid in the expulsion of semen?

The prostate gland plays a crucial role in the male reproductive system, particularly in the expulsion of semen. When ejaculation occurs, the prostate gland contracts rhythmically. This contraction is essential because it helps to expel the seminal fluid that has been secreted into the urethra, combining it with sperm from the testes to form semen.

The prostate contributes not just fluids but also helps propel the semen through the urethra during ejaculation. Its muscular structure is specifically designed for this purpose, ensuring that the semen is effectively pushed out. Understanding the function of the prostate is key in comprehending male reproductive health and the ejaculation process. Other structures, although important in reproduction, do not have this specific role in the contraction required for semen expulsion.