THE HUMAN REPRODUCTIVE SYSTEM

Sexual Reproduction – is a process whereby the sperm cell and the egg cell nuclei are brought together. These cells unite through fertilization.

Functions of the Human Reproductive System

1. production of egg and sperm cells
2. transportation and sustenance of cells,
3. development and nurturing of offspring
4. production of hormones

The Male Reproductive System

 The purpose of the organs of the male reproductive system is to perform the following functions:

• To produce, maintain, and transport sperm (the male reproductive cells) and protective fluid (semen).
• To discharge sperm within the female reproductive tract during sex.
• To produce and secrete male sex hormones responsible for maintaining the male reproductive system. 

The external sex organs of men are the penis and the scrotum.

  

Penis

• is a sensitive organ important to reproduction and urination and to sexual pleasure.
• the skin of the penis is called foreskin or prepuce. This skin is sometimes removed in a procedure called circumcision.

Testicles (testes)

• is an oval organ about 5 cm (about 2 in) long.
• are oval bodies consisting of fine tubules enclosed in a tough, fibrous sheath.
• each testis contains about 800 narrow twisting tubes, called seminiferous tubules.
• the testes are responsible for making testosterone, the primary male sex hormone, and for generating sperm.

Seminiferous tubules

• produce sperm cells or spermatozoa
• the seminiferous tubules merge and form a larger tube, the epididymis.

Epididymis

• a temporary storage place of sperms
• the minute spaces between the seminiferous tubules are filled with cells that produce the male sex hormone testosterone which controls the growth of the male reproductive system and stimulates the development of the male secondary sexual characteristics, such as the growth of the beard, the deepening of the voice, and the male contours of the body.
• a long tube coiled against the testes, where the sperm are stored and mature. 
• is a long, coiled tube that rests on the backside of each testicle. It transports and stores sperm cells that are produced in the testes. It also is the job of the epididymis to bring the sperm to maturity, since the sperm that emerge from the testes are immature and incapable of fertilization. During sexual arousal, contractions force the sperm into the vas deferens.

Vas deferens

• sperm travels from the testis through the epididymis to the vas deferens, which carries the sperm to the urethra.
• is a long, muscular tube that travels from the epididymis into the pelvic cavity, to just behind the bladder. The vas deferens transports mature sperm to the urethra, the tube that carries urine or sperm to outside of the body, in preparation for ejaculation.
• sperm exits from the urethra during ejaculation (the release of semen).

Seminal Vesicles

• are sac-like pouches that attach to the vas deferens near the base of the bladder. The seminal vesicles produce a sugar-rich fluid (fructose) that provides sperm with a source of energy to help them move. The fluid of the seminal vesicles makes up most of the volume of a man's ejaculatory fluid, or ejaculate.
• fluids from the prostate and seminal vesicles (small sacs that hold semen) combine with the sperm to form semen, a thick, yellowish-white fluid. The average discharge of semen, called ejaculate, contains approximately 300 million sperm.

Scrotum

• this is the loose pouch-like sac of skin that hangs behind and below the penis. It contains the testicles (also called testes), as well as many nerves and blood vessels. The scrotum acts as a "climate control system" for the testes. For normal sperm development, the testes must be at a temperature slightly cooler than body temperature. Special muscles in the wall of the scrotum allow it to contract and relax, moving the testicles closer to the body for warmth or farther away from the body to cool the temperature. 

How Does the Male Reproductive System Function?

The entire male reproductive system is dependent on hormones, which are chemicals that regulate the activity of many different types of cells or organs. The primary hormones involved in the male reproductive system are follicle-stimulating hormone, luteinizing hormone, and testosterone.

Follicle-stimulating hormone is necessary for sperm production (spermatogenesis), and luteinizing hormone stimulates the production of testosterone, which is also needed to make sperm. Testosterone is responsible for the development of male characteristics, including muscle mass and strength, fat distribution, bone mass, facial hair growth, voice change, and sex drive.

The Female Reproductive System

The female reproductive system is designed to carry out several functions. It produces the female egg cells necessary for reproduction, called the ova or oocytes. The system is designed to transport the ova to the site of fertilization. Conception, the fertilization of an egg by a sperm, normally occurs in the fallopian tubes. The next step for the fertilized egg is to implant into the walls of the uterus, beginning the initial stages of pregnancy. If fertilization and/or implantation does not take place, the system is designed to menstruate (the monthly shedding of the uterine lining). In addition, the female reproductive system produces female sex hormones that maintain the reproductive cycle.

The female reproductive system includes the ovaries, fallopian tubes, uterus, vagina, vulva, mammary glands and breasts. These organs are involved in the production and transportation of gametes and the production of sex hormones. The female reproductive system also facilitates the fertilization of ova by sperm and supports the development of offspring during pregnancy and infancy.


What Parts Make up the Female Anatomy?

The female reproductive anatomy includes parts inside and outside the body.

 

  


The main external structures of the female reproductive system include:

• Labia majora: The labia majora enclose and protect the other external reproductive organs. Literally translated as "large lips," the labia majora are relatively large and fleshy, and are comparable to the scrotum in males. The labia majora contain sweat and oil-secreting glands. After puberty, the labia majora are covered with hair.
• Labia minora: Literally translated as "small lips," the labia minora can be very small or up to 2 inches wide. They lie just inside the labia majora, and surround the openings to the vagina (the canal that joins the lower part of the uterus to the outside of the body) and urethra (the tube that carries urine from the bladder to the outside of the body).
• Bartholin's glands: These glands are located beside the vaginal opening and produce a fluid (mucus) secretion.
• Clitoris: The two labia minora meet at the clitoris, a small, sensitive protrusion that is comparable to the penis in males. The clitoris is covered by a fold of skin, called the prepuce, which is similar to the foreskin at the end of the penis. 
• Breasts or mammary glands: are essentially mixing factories which absorb water, sugar, and other substances from the blood and mix them together to make milk. Each breast is composed of 25 or more lobes of glands, each lobe with its duct leading to the nipple. The nipple is an erectile structure having 25 or more small openings and surrounded by a darkened area, the areola

 The internal reproductive organs in the female include:

Ovaries

• are almond-shaped glands, about 3.25 cm long, located on each side of the pelvic cavity
• these glands are designed for germinating the female reproductive cells (egg or ova) and producing the female hormones
• at birth, they contain around 200,000 to 400,000 unripe, immature eggs which are also called primary oocytes
• at the start of puberty, the ovaries also produce a hormone called estrogen which brings about changes in female sex characteristics such as a high pitched voice, absence of a beard, development of breasts, and widening of the pelvis. This hormone also stimulates the eggs to ripen

Fallopian tubes

• are also known as oviducts about 2 cm (about 0.75 in) thick and 10 to 13 cm (4 to 5 in) long. 
• are a pair of muscular tubes that extend from the left and right superior corners of the uterus to the edge of the ovaries. The fallopian tubes end in a funnel-shaped structure called the infundibulum, which is covered with small finger-like projections called fimbriae. The fimbriae swipe over the outside of the ovaries to pick up released ova and carry them into the infundibulum for transport to the uterus. The inside of each fallopian tube is covered in cilia that work with the smooth muscle of the tube to carry the ovum to the uterus.
• serve as tunnels for the ova (egg cells) to travel from the ovaries to the uterus. Conception, the fertilization of an egg by a sperm, normally occurs in the fallopian tubes. The fertilized egg then moves to the uterus, where it implants into the lining of the uterine wall.

Uterus or womb

• is a hollow, muscular, pear-shaped organ located posterior and superior to the urinary bladder.
• is about 7.6 cm (about 3 in) in length, 5 cm (2 in) in breadth, and 2.5 cm (1 in) in thickness.
• houses a developing embryo or fetus.
• it is connected to the two fallopian tubes on its superior end and to the vagina (via the cervix) on its inferior end, the uterus is also known as the womb, as it surrounds and supports the developing fetus during pregnancy. The inner lining of the uterus, known as the endometrium, provides support to the embryo during early development. The visceral muscles of the uterus contract during childbirth to push the fetus through the birth canal.

Vagina

• it also is known as the birth canal.
• is a canal that joins the cervix (the lower part of uterus) to the outside of the body. The vagina receives the penis during sexual intercourse and is a passageway for childbirth.

What does the female reproductive system do?

Its main function is to give women the ability to produce ova to be fertilized, and the space and conditions to allow a fetus to develop. In order for this to happen, the female reproductive system also has the structures necessary to allow sperm from a man to meet the ova of a woman. To do all this the female reproductive system makes its own hormones that help to control a woman's monthly cycle. These hormones cause the development and release of ova so that they can be fertilized. This process is called ovulation. They also prevent ovulation during pregnancy.

Diseases/Disorders of the Reproductive System

1. HERNIA: a structural disorder in males when the small intestine pushes through the opening where the testes descend

2. INFERTILITY: could be caused by a structural defect of the seminiferous tubles (ie: mumps can cause the testes to swell and crush the tubules), or from imperfectly formed sperm (tight pants, bike riding)

3. PELVIC INFLAMMATORY DISEASE: blocked fallopian tubes in females

4. IMPOTENCE: inability for male to have an erection, caused by hormonal imbalance, stress, nerve damage

5. VAGINITIS: caused by chemical irritation, excessive heat and moisture and or bacteria, increased discharge and itching

6. DYSMENORRHEA: is painful cramps felt before or during menstruation

7. TUMORS AND GROWTHS:

§  Polyps: fleshy growths in cervix or uterus

§  Ovarian Cyst: fluid filled sac around the ovary

§  Fibroid tumor: on muscle and connective tissue

§  Endometriosis: cells of the endometrium break off and lodge in other tissues, such as the ovaries or fallopian tubes, they begin to grow, respond to hormones, bleed, etc..

8. PROSTATE CANCER (male) is rare before the age of 50 but increases in frequency every decade thereafter. Like most tumours, prostate cancer has various causes, but it is thought to be influenced by the male sex hormone androgen.

9. CERVICAL CANCER (female) the causes of cervical cancer vary, but most cases are caused by complications associated with human papillomavirus (HPV) infection. The average age of occurrence for cancer of the cervix is age 45. Symptoms include vaginal bleeding or other discharge, pelvic pain

10. ECTOPIC PREGNANCY occurs when a fertilized egg or zygote doesn't travel into the uterus, but instead grows rapidly in the fallopian tube. Women with this condition can develop severe abdominal pain and should see a doctor because surgery may be necessary.

Vitamins and Minerals for a Healthy Reproductive System

1. Zinc is essential to the development of the reproductive organs themselves. A deficiency in zinc can result in significantly delayed sexual maturity. Zinc also serves in the regulation of male hormones and has a role in prostate functions and sperm production.
2. Iodine helps to regulate thyroid function, which in turn helps to regulate growth and body weight.
3. Folic acid can serve as a way to prevent serious birth defects by reducing the incidence of neural tube defects such as the type that causes spinal bifida.
4. B vitamins help produce red blood cells, which deliver nourishment to the fetus during a woman's pregnancy.
5. Vitamin C also helps increase sperm count in infertile men.

Keeping the Reproductive System Healthy

1. eating a proper diet low in fat and high in fiber
2. maintaining a healthy weight
3. consuming proper amounts of good-quality drinking water
4. getting adequate rest
5. engaging in regular exercise
6. not smoking or taking illegal drugs
7. drinking only moderate amounts of alcohol
8. reducing stress levels
9. keep the genital area clean
10. exercise regularly