Q. Parasympathetic nerves cause
Solution:
The penis is an erectile copulatory organ. It consists of a long shaft that enlarges to form an expanded tip, the glans penis. It is covered by a retractable and loose skin fold known as the prepuce, or foreskin. Under the skin, the penis is mainly made up of three columns of erectile tissue: one cylinder, the corpus spongiosum, along the ventral side, and two cylinders of the corpora cavernosa of the penis, present dorsally. The corpora cavernosa of the penis and the urethra are covered by dense connective tissue, the tunica albuginea. Corpus spongiosum contains the spongy urethra. Surgical removal of the prepuce is called circumcision and castration refers to the removal of testicles. The parasympathetic system causes erection and the sympathetic system causes emission and ejaculation. The parasympathetic system is responsible for the release of acetylcholine which stimulates endothelial cells to produce nitric oxide and it induces dilation that leads to an erection.
