Reproduction in Humans - ESO 3 Biology and Geology

What to Learn?

In this section: - Summary of contents covered by this page.

Overall view of the process of reproduction in humans. Key concepts: gonads, gametes, fertilisation, zygote, embryo, fetus, pregnancy, childbirth.
Sexual characteristics: primary and secundary. Puberty.
Structure of the male and female reproductive systems.
Features of the male and female gametes.
The menstrual cycle.
The reproductive process: fertilisation, implantation, fetal development and childbirth.
Hormonal control of the reproduction related activity (gametogenesis, menstrual cycle and nursing).
Contraception.
Assisted reproduction.

Basic Information

Basic Vocabulary

Adapted from Faqs.org
Gonads	Sex organs in which reproductive cells develop.
Gametes	Reproductive or sex cells. They are different to any other cell in the body in which they only have half of the chromosomes than a normal somatic cell.
Ova	Female gametes or eggs (singular: ovum).
Zygote	Fertilized ovum. By successive mitosis, it will convert into an embryo, then a fetus, and finally a newborn.
Sperm	Also spermatozoon. Mature male sex or reproductive cell. They need to be produced at a slightly lower temperature than the usual in the inside of the human body.
Acrosome	Tip of the head of a sperm cell that contains enzymes to digest the membrane of an ovum.
Scrotum	External sac enclosing the testes.
Testes	Male gonads that produce sperm cells, a 2-5% of the seminal fluid, and secrete testosterone.
Seminiferous tubules	Tightly coiled tubes within the testes that produce sperm.
Epididymis	Portion of the testes in which sperm mature or fully develop.
Vas deferens	Also ductus deferens. Passageway that carries sperm from the epididymis to the ejaculatory duct.
Seminal vesicles	Glands located at the base of the bladder that produce around a 70% of the seminal fluid.
Ejaculatory duct	Duct formed by the union of the ductus deferens and the duct of the seminal vesicle, that carries the semen up to the urethra.
Prostate	Muscular gland in males that surrounds the first inch of the urethra. It produces almost a 30% of the seminal fluid.
Bulbourethral glands	Also Cowper's glands. Glands located at the base of the penis, that at the beginning of sexual arousal secrete a fluid which helps to lubricate the urethra for spermatozoa to pass through, and to help flush out any residual urine. This fluid can carry sperms from previous ejaculations.
Penis	Male organ of reproduction and urination.
Prepuce	Also foreskin. The fold of skin over the glans or tip of the penis.
Circumcision	Surgical removal of the prepuce of the penis.
Erection	Stiffening, lengthening and rising of the penis, which occurs during sexual arousal, though it can also happen in non-sexual situations. It is primarily due to the dilation of the arteries that supply blood to the penis (which allows more blood to fill the three spongy chambers in the penis) and the constriction of the veins that carry blood away from the penis. This way, more blood enters than leaves the penis until an equilibrium is reached and a constant size is achieved.
Ejaculation	Sudden ejection of semen from the penis.
Semen	Thick, whitish, somewhat sticky fluid composed of sperms and seminal fluid that is propelled out of a male's reproductive tract during ejaculation. Normal human ejaculated semen, as defined by the WHO, has a volume of 2 ml or greater, pH of 7.2 to 8.0 (slightly alkaline), sperm concentration of 20 million spermatozoa per ml or more, and a motility of 50% of the spermatozoa, with at least a 25% being able to move forward.
Ovaries	Female gonads in which ova are produced and that secrete estrogens and progesterone.
Ovarian follicles	Structures within an ovary consisting of a developing egg surrounded by follicle cells.
Corpus luteum	Yellowish remains of a burst ovarian follicle that secretes progesterone.
Ovulation	Release of a mature ovum from an ovary.
Fimbriae	Fingerlike projections at the end of a fallopian tube that partially surround an ovary.
Fallopian tubes	Also ovarian tubes. Tubes connecting an ovary to the uterus and through which an ovum is transported. They are the place of fertilization.
Uterus	Also womb. The hollow organ in females that receives, retains, and nourishes a fertilized ovum or egg.
Myometrium	Middle layer of the uterus composed of interwoven muscle cells.
Endometrium	Inner layer of the uterus that provides nourishment for a developing embryo and fetus and that sloughs off during the regular menstrual cycle.
Cervix	Lower necklike portion of the uterus leading into the vagina.
Vagina	Muscular tube in women that extends from the cervix of the uterus to the vaginal opening.
Vulva	Female external genital organs, composed of the mons pubis, the labia majora, the labia minora, the clitoris, the urethral opening, the vaginal opening and the greater vestibular glands.
Mons pubis	Fatty, rounded, hairy area at the top of the vulva.
Labia majora	Outer, hairy skin folds of the vagina.
Labia minora	Inner skin folds of the vagina.
Clitoris	Small protruding mass of erectile tissue at the top of the labia minora.
Greater vestibular glands	Pair of mucus-secreting glands that lubricate the lower portion of the vagina.
Hymen	Thin membrane partially covering the external opening of the vagina.
Menarche	Beginning of menstruation or the first menstrual period.
Menopause	Period in a woman's life when menstrual activity ceases.
Menstruation	Also menses. Periodic (monthly) discharge of blood, secretions, tissue, and mucus from the endometrium in the absence of pregnancy.
Chorion	The outermost membrane that surrounds the embryo/fetus during pregnancy. It is in contact with the amnion and generates the placenta.
Amnion	Fluid-filled sac that surrounds a developing embryo/fetus. It provides room and cushioning to the embryo/fetus.
Placenta	Temporary organ developed after the implantation of an embryo, when the chorionic villi invade the endometrium. It provides nutrients to a developing fetus, carries away wastes, and produces hormones such as estrogens and progesterone.
Umbilical cord	Structure that connects the embryo/fetus to the placenta.
Alveolar glands	Glands within the mammary glands that produce milk.
Lactiferous ducts	Ducts that carry milk from the alveolar glands to the surface of the nipple of a breast.
Areola	Circular, darkened area surrounding the nipple of each breast.
Luteinizing hormone	Hormone secreted by the anterior pituitary that stimulates, in women, ovulation and the release of estrogens and progesterone by the ovaries and, in men, the secretion of testosterone by the testes.
Follicle-stimulating hormone	Hormone produced by the anterior pituitary gland that stimulates the development of follicles in the ovaries of females and sperm in the testes of males.
Testosterone	Male hormone secreted by the testes that stimulates the growth of the male reproductive organs and brings about the secondary sex characteristics.
Estrogens	Female hormones secreted by the ovaries that bring about the secondary sex characteristics and regulate the female reproductive cycle.
Progesterone	Female hormone secreted by the ovaries that makes the uterus more ready to receive a fertilized ovum and regulate the female reproductive cycle.
Prolactin	Hormone secreted by the anterior pituitary that stimulates the mammary glands to produce milk during nursing.
Oxytocin	Hormone produced by the hypothalamus and stored in the posterior pituitary that stimulates contraction of the uterus during childbirth and secretion of milk during nursing.

External Links

General

How sex works.Introduction to how human reproduction works, with a general overview on most of the aspects involved and, most importantly, several movies detailing some of them.

Puberty

KEWL - Puberty.Basic introduction to changes that boys and girls undergo in puberty.

Puberty at Hillendale Health.Questions and answers about puberty and its changes. Includes a glossary.

Reproductive System

Male reproductive system at Hillendale Health.Questions and answers about the male reproductive system. Includes a glossary.

Female reproductive system at Hillendale Health.Questions and answers about the female reproductive system. Includes a glossary.

Male reproductive system at Web-books.com.Very good overall view, with images and text, on the male reproductive system, with its organs and their functions. The left menu contains a link to a wide series of reproductive diseases.

Female reproductive system at Web-books.com.Very good overall view, with images and text, on the female reproductive system, with its organs and their functions. The left menu contains a link to a wide series of reproductive diseases.

The reproductive system at Faqs.org.Another wide overall view, with text and images, on all the organs of the male and female reproductive systems and the way they work, sexual hormones, birth control methods, embrionary development, the reproductive system disorders, a glossary and additional readings.

The reproductive system.To dig deeper, visit this website with lots of info and images on the reproductive system.

Review activities at Hillendale Health.Six diffrerent quizzes to test ypur knowledge about the reproductive systems, puberty, menstrual cycle, conception and more.

From Conception to Birth

Fetal development.Description and images of the stages of the embryonic and fetal development.

Baby growth and birth at Hillendale Health.Questions and answers about conception, embryonic development and birth. Includes a glossary.

Sexuality

Sexuality at Faqs.org.A wide overall view, with text and images, on everything you ever wanted to know about sexuality, stages of sexual development, menstruation, sex, birth control, pregnancy, sexually transmitted diseases. With a glossary.

Movies, Animations and Audios

In this section: - Series of movies and animations related to this page's topic.

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Reproductive System

Female reproductive system.The female reproductive system with some detail.

From Conception to Birth

Reproduction.Short introductory video to the reproductive process in humans.

Conception.See how conception takes place.

From conception to the fifth month.Detailed video on the events of the first months of fetal development.

From weeks 6 to 12.Animation showing the changes between the sixth and the twelfth week of gestation.

Development of the fetus (I).Stage by stage description of the changes during human fetal development.

Development of the fetus (II).Stage by stage depiction of the human fetal development.

Childbirth (I).Animation of a normal vaginal birth.

Childbirth (II).Detailed explanation on how a typical childbirth takes place.

Some Fun

Childbirth the Monty Python's way.Fragment from the Monty Python's film "The meaning of Life"... with the very expensive machine that goes "ping". You can read the transcript at http://www.mwscomp.com/movies/mol/m-03-i.htm.

Images

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