Human Reproductive System: Organs, Anatomy, Functions, and Diseases

IBYXO - Humans have many organs, one of which plays a role in the reproductive system. This reproductive system is used for the process of forming new individuals.

Every living thing will reproduce for the continuation of its kind. Likewise with humans, experiencing reproduction for their survival. To explain everything, see the material below.

The Human Reproductive System

A. Reproductive Organs

Reproduction is the process of forming new individuals. Reproduction aims to preserve the species from extinction. Reproduction in humans is classified as sexual reproduction. The human reproductive system involves a male parent and a female parent. In the human reproductive system, each parent has reproductive organs.

The human reproductive system will begin to function when a person reaches maturity (puberty) or puberty. In a man, his testes have been able to produce male genital cells (sperm) and the hormone testosterone. While a woman's ovaries have been able to produce eggs (ovum) and female hormones, namely estrogen. The human reproductive system is divided into male and female reproductive organs.

1. Male reproductive organs 

The male reproductive organs have two reproductive functions, namely the production of genital cells and the release of cells into the female genital tract. The male reproductive organs consist of four main parts, namely the testes, vas deferens, sperm sac, and penis. For easier understanding, these organs are divided into internal and external reproductive organs.

a. Internal reproductive organs

1. Testes, numbering a pair, are contained in a protective pouch called the scrotum and are located outside and below the pelvic cavity. The testes function to produce the hormone testosterone and male genital cells (spermatozoa). The hormone testosterone serves to cause secondary genital signs in men.

2. Expenditure channels consisting of: 

• Vas efferens, is a channel connecting the seminiferous tubules with the epididymis.
• Epididymis, is a place of maturation and storage of sperm. The epididymis is a winding channel located in the scrotum. 
• Vas deferens (sperm duct), a continuation of the epididymis duct, functions to channel sperm to the urethra. 
• Urethra, is a continuation of the vas deferens, serves to channel sperm out and is a channel for urine from the bladder to the outside.

3. Genital glands

• Vesica seminalis, is a winding gland and is located behind the bladder. This gland produces liquid energy sources for sperm. 
• Prostate gland, which is a semen-producing gland. 
• Cowpery's gland or glandula bulbourethralis, this gland is located along the urethra, functioning to excrete urine-neutralizing mucus that remains in the urethra.

b. External reproductive organs

1. The penis is the outermost genital organ, functioning for copulation, which is to insert sperm into the reproductive tract in women. Inside there are sperm ducts and urine channels. 

2. The scrotum is a skin bag that protects the testicles, totaling a pair separated by a partition in the form of smooth muscle and connective tissue.

2. Female reproductive organs 

Just like the male reproductive organs, the female reproductive organs are divided into internal and external reproductive organs. 

a. Internal reproductive organs

1. Ovaries (ovaries) are a pair, function for the formation of eggs and produce the hormones estrogen and progesterone. The hormone estrogen serves to cause secondary genital signs in women.

2. A pair of funnel infundibulum, serves to capture eggs from the ovaries. 

3. A pair of Fallopian tubes or oviducts, which are oviducts, serves as a place for fertilization (conception). 

4. Uterus (uterus), serves as a place of development and growth of the fetus. The human uterus is simplex type, which has only one room. The lower part of the uterus shrinks and is called the cervix uteri, while the large part is called the corpus uteri (uterine body). The uterine wall consists of three layers, namely the perimetrium, myometrium, and endometrium. 

5. Vagina, serves as an organ of copulation and to give birth to babies. The organ has many folds so that during childbirth it can expand.

b. External reproductive organs 

The external reproductive organs consist of the vulva which is the area that envelops the vagina. The vulva consists of the base of the mons pubis, labia, clitoris, the outer end of the vagina, and the urinary tract. 

1. The mons pubis is a mound of fatty tissue located at the bottom of the abdomen and covered by pubic hair.

2. The labia are lip-like folds located at the base of the mons pubis. Labia consists of two lips, namely the outer lip (mayora) which is a thick and large lip and the inner lip (minora) which is a thin lip that guards the entrance to the vagina. 

3. The clitoris is located at the meeting between the two labia minora and the base of the mons pubis. The size is very small pea-sized, full of sensory nerve cells and blood vessels. 

4. The mouth of the urinary tract (orificium urethrae) is just below the clitoris. 

5. The hymen is below the urethra.

B. Genital Cell Formation 

Humans reproduce sexually and at a certain time will form genital cells (gametes). The genital cells that a man forms are called sperm cells (spermatozoa). An adult male produces more than one hundred million sperm cells every day. The genital cells formed by a woman are called eggs (ovum). The process of spermatozoa formation is called spermatogenesis, while the process of ovum formation is called oogenesis. Both processes initiate the occurrence of reproduction in humans. 

A woman is able to produce eggs (ovum) after puberty (early adolescence) until adulthood, which is around the age of 12 to 50 years. After the age of about 50 years a woman is no longer productive which is characterized by not having menstruation. This period is called menopause.

1. Male genital cell formation 

The process of sperm formation and maturation is called spermatogenesis. Spermatogenesis occurs in the seminiferous tubules of the testes: The tubules contain sperm cells, called spermatogonium. The spermatogonium then divides mitotically to produce a haploid spermatogonium. This spermatogonium then enlarges to form primary spermatocytes. The primary spermatocyte will then divide by meiosis I to produce two haploid secondary spermatocytes. Then each secondary spermatocyte will divide by meiosis II to produce two haploid spermatids. The spermatid cells will differentiate into spermatozoa or sperm.

2. Female genital cell formation 

The process of ovum formation is called oogenesis and occurs in the ovaries. Ovum formation begins with mitotic division of the outer layer of the ovary to form a diploid oogonium. This entire structure is called the primary follicle. As the follicle grows, the primary oocyte divides in meiosis I to produce one secondary oocyte and a polar body. The secondary oocyte then develops into a haploid ovum ready to be fertilized by sperm.

C. Fertilization and Embryo Development 

Fertilization is the process of fertilizing an ovum by sperm. Fertilization is preceded by ovulation, which is the release of a mature egg from the ovary. If the sperm meets the ovum, fertilization will occur. Fertilization occurs in the oviduct. The fertilized egg will form a zygote. The formed zygote is immediately enveloped by a membrane, then heads to the uterus. In the uterus, the zygote implants itself in the uterine wall (endometrium) which has thickened and contains many blood vessels. 

The zygote that has been in the uterus will continue to grow and develop into an embryo until it is born. The embryonic period / human pregnancy period is about 9 months 10 days In the womb, the embryo gets food from the mother's body through the placenta (ari-ari). The embryo in the womb is protected by the following membranes.

1. Amnion

Amnion is a membrane that limits the room where the embryo is located. The amnion wall secretes sap in the form of amniotic fluid which is useful for keeping the embryo wet and resisting shocks. 

2. Chorion

Chorion is a membrane that is on the outside of the amnion. The chorion and alantois will grow to form a spike of blood vessels associated with the parent's blood circulation through the placenta. 

3. Sacus vitellinus (Yolk sac) 

The sacus vitellinus is located between the amnion and the placenta. The sacus vitellinus is the first appearance of cells and blood vessels.

4. Alantois 

The alantois is located inside the umbilical cord. The allantois functions for respiration, food channels, and excretion. 

As the embryo develops, the epithelial tissue disappears and there are only blood vessels that function as a link between the embryo and the placenta. If after ovulation the egg is not fertilized by a sperm cell, the uterine wall tissue that has thickened and contains blood vessels will be damaged and shed, called menstruation (menstruation).

D. Menstrual Process and Cycle 

Menstruation is bleeding that occurs due to the shedding of the inner wall of the uterus (endometrium) which contains many blood vessels because there is no embryo attached. If there is no embryo attachment, then this layer will fall off, then the blood comes out through the cervix and vagina. This bleeding occurs periodically, the time interval between one menstruation and the next menstruation is known as one menstrual cycle. 

Women's menstrual cycles vary, but the average is around 28 days. The first day of menstruation is declared as the first day of the menstrual cycle. This cycle consists of four phases, namely:

1. The menstrual phase 

This menstrual phase occurs if the ovum is not fertilized by sperm, so the corpus luteum stops producing the hormones estrogen and progesterone. The decrease in estrogen and progesterone levels causes the release of the ovum from the endometrium which is accompanied by tearing and shedding of the endometrium, resulting in bleeding. This menstrual phase lasts approximately 5 days. Blood that comes out during menstruation ranges from 50-150 mL. 

2. Preovulatory phase 

The preovulation phase is also called the poliferation phase. Gonadotropin liberating hormone released by the hypothalamus will spur the pituitary to secrete FSH (Follicle Stimulating Hormone) to spur follicular maturation and stimulate follicles to secrete estrogen. The presence of estrogen causes the re-formation (poliferation) of the endometrial wall. Increased estrogen levels also cause the cervix to secrete mucus which is alkaline. This mucus serves to neutralize the acidic atmosphere in the vagina so that it supports sperm life. 

3. Ovulation phase

Increased estrogen levels inhibit FSH production, then the pituitary secretes LH (Luteinizing Hormone). Increased levels of LH stimulate the release of secondary oocytes from the follicle or ovulation. 

4. Post-ovulation phase

Although the length of the menstrual cycle varies, the postovulation phase is always the same, which is 14 days before the next menstruation. The de Graaf follicle (mature follicle) that has released the secondary oocyte will wrinkle and become a corpus luteum. The corpus luteum secretes the hormone progesterone and still secretes estrogen but not as much as when it was a follicle. Progesterone supports the work of estrogen to thicken and grow blood vessels in the endometrium and prepare the endometrium to accept embryo attachment in the event of fertilization or pregnancy. If fertilization does not occur, the corpus luteum will turn into a corpus albikan which only secretes a few hormones, so that progesterone and estrogen levels become low. This situation causes menstruation, and so on.

E. Diseases of the Human Reproductive Organs 

Diseases of the human reproductive system (venereal diseases) can be caused by viruses or bacteria. In general, venereal diseases are transmitted through sexual intercourse. 

1. Syphilis

Syphilis is caused by infection with the bacterium Treponema pallidum. Signs of syphilis include sores on the genitals, rectum, tongue and lips; swollen lymph nodes on the thighs; spots all over the body; painful bones and joints; rashes on the body, especially the hands and soles of the feet.

2. Gonorrhea (gonorrhea)

Gonorrhea is caused by the bacteria Neisseria ghonorrhoeae. Symptoms of gonorrhea include pus-like discharge from the genital tract, burning, and frequent urination. 

3. Genitals herpes

Genital herpes is caused by the Herpes simplex virus. Symptoms of herpes genetalis include itching or pain in the genital area and open sores or watery blisters. 

4. AIDS (Acquired Immuno Deficiency Syndrome)

AIDS is caused by the HIV (Human Immuno-deficiency Virus) virus, which attacks certain white blood cells, compromising the immune system.