Reproductive System:

The reproductive system is a collection of internal and external organs - in both males and females - that work together for the purpose of procreating, according to the Cleveland Clinic. Due to its vital role in the survival of the species, many scientists argue that the reproductive system is among the most important systems in the entire body.

The male reproductive system consists of two major parts: the testes, where sperm are produced, and the penis, according to Merck Manuals. The penis and urethra belong to both the urinary and reproductive systems in males. The testes are carried in an external pouch known as the scrotum, where they normally remain slightly cooler than body temperature to facilitate sperm production.

The external structures of the female reproductive system include the clitoris, labia minora, labia majora and Bartholin's glands, according to the Cleveland Clinic. The major internal organs of the female reproductive system include the vagina and uterus - which act as the receptacle for semen - and the ovaries, which produce the female's ova. The vagina is attached to the uterus through the cervix, while the fallopian tubes connect the uterus to the ovaries. In response to hormonal changes, one ovum, or egg - or more in the case of multiple births - is released and sent down the fallopian tube during ovulation. If not fertilized, this egg is eliminated as a result of menstruation.

Fertilization occurs if a sperm enters the fallopian tube and burrows into the egg, according to WebMD. While the fertilization usually occurs in the oviducts, it can also happen in the uterus itself. The egg then becomes implanted in the lining of the uterus, where it begins the processes of embryogenesis (in which the embryo forms) and morphogenesis (in which the fetus begins to take shape). When the fetus is mature enough to survive outside of the womb, the cervix dilates and contractions of the uterus propel it through the birth canal. 

Defining and treating infertility

Infertility is defined as a couple's inability to conceive after one year of unprotected intercourse. It can be caused by a condition in one partner or a combination of circumstances, according to the Mayo Clinic.

In males, infertility is a condition in which they produce no sperm cells (azoospermia) or too few sperm cells (oligospermia), or their sperm cells are abnormal or die before they can reach the egg. Causes range from chromosomal defects to hormonal imbalance to tumors. Lifestyle factors, such as drug and alcohol use, can also play role. In rare cases, infertility in men is caused by an inherited condition, such as cystic fibrosis, according to the Mayo Clinic.

In women, infertility is defined as a disorder of the reproductive system that hinders the body's ability to ovulate, conceive, or carry an infant to term.

Reproductive conditions are treated by a variety of specialists. In women, many issues are treated by obstetricians/gynecologists and for males urologists handle many disorders of their reproductive systems. There are also infertility experts that treat couples who are unable to conceive and endocrinologists who treat hormonal disorders.

Information Taken from: https://www.livescience.com/26741-reproductive-system.html