Two chambers called the corpora cavernosa, which run the length of the organ and contain a maze of blood vessels shaped like cavernous spaces like a sponge The urethra, or channel for urine and sperm, which runs along the underside of the corpora cavernosa Erectile tissue, which surrounds the urethra, two main arteries and several veins and nerves The shaft, the longest part of the penis The head glanswhich is at the end of the shaft The meatus, or opening at the tip of the head where urine and semen are discharged How does an erection occur? These genes come from the father's sperm and the mother's egg, which are produced by the male and female reproductive systems. How effective is withdrawal? The testicles are also part of the endocrine system because they produce hormones, including testosterone. If your son has symptoms of a problem with his reproductive system, talk with your doctor — many problems with the male reproductive system can be treated.
At this stage, the ejaculation is unstoppable.
How It Occurs The blood vessels in the penis relax and open up, allowing blood to fill them. Each time a guy ejaculates, it can contain up to million sperm. Unlike the female, whose sex organs are located entirely within the pelvis, the male has reproductive organs, or genitals, that are both inside and outside the pelvis. The head contains genetic material genes. It takes sperm about 4 to 6 weeks to travel through the epididymis.