Ability to Maintain Erection is the Primary Key to Human Reproduction

In humans, the penis is the male sexual organ of copulation. The penis deposits semen into the vagina during sexual intercourse and carries urine through the urethra during urination. It consists primarily of erectile tissue that becomes engorged with blood during sexual excitement, resulting in an erection. The penis includes the shaft (tubular portion), glans (penis tip and sexual sensation area), and the prepuce, or foreskin (loose skin fold over glans). The prepuce is normally removed during circumcision. The ability to maintain erection of the penis is the primary key to human reproduction; without this ability by men, reproduction of the human species will cease. Erection enables sexual intercourse and begins with sensory and mental stimulation resulting in engorgement of the spiral helicine arteries and the plentiful venous sinuses of the organ. Erection of the penis to its firm stiffening state, which occurs during sexual arousal, depends on a complex interaction of psychological, nervous, vascular and endocrine factors. Autonomic dilation of the arteries supplying blood to the penis, which allows blood to fill the erectile tissue chambers of the penis, is the primary physiological mechanism underlying erection. The process causes the penis to lengthen and stiffen. Inability to have and maintain an erection firm enough for normal and satisfactory sexual performance is known as erectile dysfunction (ED) or impotence. Major causes of erectile dysfunction include diabetes and the aging process. ED is treatable at all ages. Treatments include psychotherapy, drug therapy, and surgery. The testes are located in the scrotum and hangs outside the male body. The cooler outside temperature is conducive to normal sperm production. The production of these male reproductive cells takes place in the coiled seminiferous tubules contained in each testis. Located between the seminiferous tubules are clusters of endocrine secretary cells called Leydig cells which produce androgens (male steroid hormones), mostly testosterone. Because they produce sperm and male sex hormones, particularly testosterone, the paired testes are components of both the reproductive system and the endocrine system. The sperm-forming and endocrine functions of the testes are controlled by gonadotropin hormones produced by the pituitary gland. The testicles are very sensitive to impact and injury. Prolonged sexual arousal can produce "blue balls" a slang term used to describe temporary fluid accumulation around the testes and the prostate. Major disorders of the testicles include testicular cancer, swelling of the testes, inflammation of the testes, otherwise known as orchitis; testicular torsion, also called spermatic cord torsion; inflammation of the epididymis, called epididymitis; varicocele (swollen vein from the testes, usually affecting the left testicle, and absence of one or both testes, known as anorchidism.