human male reproductive system


Image Caption : Male Pelvis Showing Reproductive System : The male reproductive system includes the penis, testes, duct system (consisting of epididymis and vas deferens), and accessory glands, which include seminal vesicles and the prostate. Testosterone is the principal sex hormone in males, responsible for the maturation of sex organs and production of sperm, as well as secondary sexual characteristics such as growth of body and facial hair, increased muscle mass, and a deepening voice; testosterone also plays other metabolic roles in the body and is produced in small amounts by females.

MALE REPRODUCTIVE SYSTEM

The male reproductive system, like that of the female, consists of those organs whose function is to produce a new individual, i.e., to accomplish reproduction. This system consists of a pair of testes and a network of excretory ducts (epididymis, ductus deferens (vas deferens), and ejaculatory ducts), seminal vesicles, the prostate, the bulbourethral glands, and the penis.

Illustration of the male reproductive system

INTRODUCTION TO THE REPRODUCTIVE SYSTEM

The major function of the reproductive system is to ensure survival of the species. Other systems in the body, such as the endocrine and urinary systems, work continuously to maintain homeostasis for survival of the individual. An individual may live a long, healthy, and happy life without producing offspring, but if the species is to continue, at least some individuals must produce offspring.

Within the context of producing offspring, the reproductive system has four functions:

  • To produce egg and sperm cells
  • To transport and sustain these cells
  • To nurture the developing offspring
  • To produce hormones

These functions are divided between the primary and secondary, or accessory, reproductive organs. The primary reproductive organs, or gonads, consist of the ovaries and testes. These organs are responsible for producing the egg and sperm cells gametes), and hormones. These hormones function in the maturation of the reproductive system, the development of sexual characteristics, and regulation of the normal physiology of the reproductive system. All other organs, ducts, and glands in the reproductive system are considered secondary, or accessory, reproductive organs. These structures transport and sustain the gametes and nurture the developing offspring.

GONADS

The gonads, the primary reproductive organs, are the testes in the male and the ovaries in the female. These organs are responsible for producing the sperm and ova, but they also secrete hormones and are considered to be endocrine glands.

TESTES

Illustration of a testis within the male reproductive system

Male sex hormones, as a group, are called androgens. The principal androgen is testosterone, which is secreted by the testes. A small amount is also produced by the adrenal cortex. Production of testosterone begins during fetal development, continues for a short time after birth, nearly ceases during childhood, and then resumes at puberty. This steroid hormone is responsible for:

  • The growth and development of the male reproductive structures
  • Increased skeletal and muscular growth
  • Enlargement of the larynx accompanied by voice changes
  • Growth and distribution of body hair
  • Increased male sexual drive

Testosterone secretion is regulated by a negative feedback system that involves releasing hormones from the hypothalamus and gonadotropins from the anterior pituitary.

National Cancer Institute / NIH

The male reproductive system consists of a number of sex organs that play a role in the process of human reproduction . These organs are located on the outside of the body and within the pelvis.

The main male sex organs are the penis and the testicles which produce semen and sperm, which, as part of sexual intercourse, fertilize an ovum in the female's body; the fertilized ovum (zygote) develops into a fetus, which is later born as an infant.

The corresponding system in females is the female reproductive system.



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