The answer here is CORPUS CAVERNOSUM containing the erectile tissue. The male urethra travels through the penis and is the passageway of semen and urine. It is surrounded by erectile tissue which facilitates penile erection. The penis, on the other hand, is composed of three cylinders wrapped in a fascia: corpus spongiosum and two corpus cavernosa. The corpus cavernosa is the one containing the erectile tissue which facilitates penile erection. Erectile tissue is capable of stiffening and engorgement of blood. During sexual intercourse, there is an increase of blood flow in the erectile tissue and becomes it filled with blood resulting to stiffening or enlargement of the penis.
