The penis, or organ of copulation of the male, is a short, cylindrical, pendulous body that is suspended from the front and sides of the pubic arch. It is composed of three cylindrical masses of cavernous erectile tissue bound together by fibrous strands and covered with skin. The lateral two masses are known as the corpora cavernosa penis. The third, known as the corpus cavernosum urethrae or spongiosum, makes up the vertral surface and contains the urethra.
At the end of the penis there is a slight enlargement known as.the glans penis that contains the external urethral orifice (meatus) and the sensory end organs that are stimulated during sexual intercourse. These end organs convey impulses to the spinal cord via the pudendal nerves. Their endings synapse on the sacral preganglionic cell bodies of the parasympathetic nervous system to produce erection and upon preganglionic cell bodies of the sympathetic nervous system to produce emission of the semen.
