Published on March 9, 2014
The Human Reproductive System Grade 12 T. SIBEKO
• Table of Contents • The structure of the male reproductive systems • The structure of the female reproductive systems • Male secondary sex characteristics • Female secondary sex characteristics • Gametogenesis • Menstrual Cycle • Gestation • Implantation and Development
Male Reproductive System • The human male reproductive system consists of a number of sex organs that are a part of the human reproductive process. In the case of men, these sex organs are located outside a man's body, around the pelvic region.
Male Reproductive System 1. Penis 2. Testicles( Scrotum) 3. Epididymis
Male Reproductive System Penis • The penis has a long shaft and enlarged tip called the glans penis. • The penis is the male copulatory organ. • When the male becomes sexually aroused, the penis becomes erect and ready for sexual intercourse. • .
Male Reproductive System • Erection is achieved because blood sinuses within the erectile tissue of the penis become filled with blood. The arteries of the penis are dilated while the veins are passively compressed so that blood flows into the erectile cartilage under pressure. • The male penis is made of two different tissues,and soft spongey tissue. • Cartlidge is not in the penis
Testicles • The testes hang outside the abdominal cavity of the male within the scrotum. They begin their development in the abdominal cavity but descend into the scrotal sacs during the last 2 months of fetal development. This is required for the production of sperm because internal body temperatures are too high to produce viable sperm.
Epididymis • The epididymis is a whitish mass of tightly coiled tubes cupped against the testicles. • It acts as a storage place for sperm before they enter the vasa deferentia, tubes that carry sperm form the testes to the urethra.
Female reproductive system
Female reproductive system
Female reproductive system Contents • 1 Vagina • 2 Cervix • 3 Uterus • 4 Oviducts • 5 Ovaries
Female reproductive system • Vagina (Latin,="sheath"or "scabbard") • Fibromuscular tubular tract leading from the uterus to the exterior of the body in female • “Vagina" is often used to refer to the Vulva or female genitals generally; strictly speaking, the vagina is a specific internal structure and the vulva is the exterior genitalia only.
Female reproductive system • The vagina is the place where semen from the male is deposited into the female's body at the climax of sexual intercourse, commonly known as ejaculation. Around the vagina, pubic hair protects the vagina from infection and is a sign of puberty
Female reproductive system • Cervix • The cervix is the lower, narrow portion of the uterus where it joins with the top end of the vagina. • It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall. • Approximately half its length is visible; the remainder lies above the vagina beyond view.
Female reproductive system • Uterus • The uterus or womb is the major female reproductive organ of humans. One end, the cervix, opens into the vagina; the other is connected on both sides to the fallopian tubes.
UTERUS • The uterus is a pearshaped muscular organ. • Its major function is to accept a fertilized ovum which becomes implanted into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. • The fertilized ovum becomes an embryo, develops into a fetus and gestates until childbirth.
OVIDUCTS • Oviducts: Fallopian tube • The Fallopian tubes or oviducts are two very fine tubes leading from the ovaries of female mammals into the uterus.
OVIDUCTS • On maturity of an ovum, the follicle and the ovary's wall rupture, allowing the ovum to escape and enter the Fallopian tube. • There it travels toward the uterus, pushed along by movements of cilia on the inner lining of the tubes. This trip takes hours or days. • If the ovum is fertilized while in the Fallopian tube, then it normally implants in the endometrium when it reaches the uterus, which signals the beginning of pregnancy
Ovaries • The ovaries are the place inside the female body where ova or eggs are produced. • The process by which the ovum is released is called ovulation. The speed of ovulation is periodic and impacts directly to the length of a menstrual cycle.
• After ovulation, the ovum is captured by the oviduct, after traveling down the oviduct to the uterus, occasionally being fertilized on its way by an incoming sperm, leading to pregnancy and the eventual birth of a new human being.
Male Secondary Sex Characters Male – Growth of body hair, including underarm, abdominal, chest, and pubic hair. – Loss of scalp hair androgenic alopecia can also occur – Greater mass of thigh muscles in front of the femur, rather than behind it as is typical in mature females – Growth of facial hair – waist
Male Secondary Sex Characters – Enlargement of larynx and deepening of voice – Increased stature; adult males taller than adult females, on average – Heavier skull and bone structure – Increased muscle mass and strength – Broadening of shoulders and chest; shoulders wider than hips
Male Secondary Sex Characters – Increased secretions of oil and sweat glands, often causing acne and body odor  – Coarsening or rigidity of skin texture, due to less subcutaneous fat – A prominent Adam's apple • Fat deposits mainly around the abdomen and
Male Secondary Sex Characters – Higher waist to hip ratio than prepubescent or adult females or prepubescent males, on average – On average, larger hands and feet than prepubescent or adult females or prepubescent males • Lower digit ratio, on average
Female Secondary Sex Characters – Enlargement of breasts – Growth of body hair, most prominently underarm and pubic hair – Greater development of thigh muscles in back (behind the femur) than in front of it – Vaginal and uterine growth
Female Secondary Sex Characters – Decreased stature; adult females shorter stature than adult males, on average – Widening of hips; lower waist to hip ratio than adult males, on average – Upper arms approximately 1" longer, on average, for a given height – Changed distribution in weight and fat; more subcutaneous fat and fat deposits mainly around the buttocks, thighs and hips • Higher digit ratio, on average
Gametogenesis is a process in which diploid or haploid cells undergo cell division and differentiation to form mature haploid gametes.
Gametogenesis • Occurs by meiotic division of diploid gametocytes into various gametes, or by mitotic division of haploid gametogenous cells. • The existence of a multicellular, haploid phase in the life cycle between meiosis and gametogenesis is also referred to as alternation of generations.
Gametogenesis is simply… • The process of gametes formation • It occurs in the gonads (ovary or testis)
Spermatogenesis is the process of formation of the male germ cells (sperm formation). It occurs in the seminiferous tubules of the testis. It is thread-like in shape.
Spermatogenesis occurs from puberty to old age, producing immense numbers of spermatozoa at an average rate of 1.5 million spermatozoa per minute. The sperm will mature in the epidiymis, nourished by sertoli cells for up to 10 weeks. Humans aged 13-90 can make 1 billion sperm a day.
The sertoli cells are supporting cells that have several functions. They form the blood-testes barrier: nutrients, and circulating substances do not directly reach the germ cells The sertoli cells determine which substances reach the germ cells The spermatogonia are outside the blood-testis barrier. They also produce antigen-binding proteins, which are necessary for spermiogenesis (morphological development of spermatids to spermatozoa).
Spermatogenesis is the process by which male primary sperm cells undergo meiosis, and produce a number of cells termed spermatogonia, from which the primary spermatocytes are derived. Each primary spermatocyte divides into two secondary spermatocytes, and each secondary spermatocyte into two spermatids or young spermatozoa. These develop into mature spermatozoa, also known as sperm cells. The primary spermatocyte gives rise to two cells, the secondary spermatocytes, and the two secondary spermatocytes by their subdivision produce four spermatozoa.
Oogenesis is the process of formation of the female germ cells (egg formation). It happens in the Ovary. It is Spherical in shape.
Oogenesis begins in early foetal life. All oocytes formed in females are produced during foetal life. Many of them degenerate with time and at birth the ovaries contain about 2 million oocytes. All the oocytes go into meiotic arrest when they reach the first meiotic division during foetal life. The primary oocytes remain in the prophase of the first meiotic division until the time of puberty, when they are gradually released to complete meiosis at regular intervals known as the ovarian cycle. On the average only one oocyte matures during each cycle, which occurs at approximately monthly intervals, so that the total amount of oocytes to be ovulated is about 500 oocytes in a lifetime.
Oogonium/Oogonia Diploid in number: 44 autosomes and 2 sex cells It is very small and under the process of development. Undergoing G1-S.
Females undergo a phase called the Menstrual Cycle
Physiology of menstruation the ovaries... • 1. Hypothalamus releases GnRH (LHRH) • 2. Release of GnRH triggers APG to release FSH and LH – FSH- responsible for the maturation of ovum and follicle formation. – Causes an increase in estrogen – LH – triggers ovulation and growth of uterine lining
• 2.1 FSH activates primordial follicles to mature. • 2.2 Primordial follicles start producing follicular fluid that is HIGH IN ESTROGEN (estradiol) and some progesterone • 2.3 primordial follicles propelled toward the surface of ovary and is now called Graafian Follicle. – 3. Graafian follicle undergoes cell division (mitosis, meiosis) • 3.1 GF divides into: – 3.1.a primary oocyte – with more cytoplasm – 3.1.b secondary oocyte – with less cytoplasm • 3.2 GF after meiosis contain haploid cells (23 chromosomes)
• 4. Upsurge in LH causes the release of prostaglandin • 5. Prostaglandin causes the rupture of GF releasing ovum and follicular fluid from the follicle, leaving the follicle with a hollowed pit. • 6. Increase in LH causes production of Lutein (bright yellow fluid, HIGH IN PROGESTERONE) that will fill the empty pit • 7. Follicle becomes “CORPUS LUTEUM”
– 7.1 if fertilization occurs, ovum implants at the uterus, corpus luteum stays inside the ovaries until 16-20 weeks; trophoblast begin secreting HCG – 7.2 without fertilization, ovum atrophies after 4-5 days, CL remains for only 8-10 days. – 7.2.a CL replaced by white fibrous tissue, CL becomes “CORPUS ALBICANS”
Physiology of menstruation the uterus... 1st PHASE: PROLIFERATIVE (aka estrogenic/follicular/postmenstrual ) High levels of estrogen causes thickening and proliferation of endometrium LH is increased, Estrogen is increased
2nd PHASE: SECRETORY (aka: progestational/luteal/premenstrual) Increased levels of progesterone causes glands at endometrium to become cork screw like or twisted in appearance and dilated with quantities of glycogen and mucin Increased in capillaries making endometrium appear like a rich spongy velvet Decreased LH, Increased Progesterone
3RD PHASE: ISCHEMIC Decreased estrogen and progesterone levels causes the degeneration of the endometrium Capillaries rupture, endometrium sloughs off
4TH PHASE: MENSES/MENSTRUAL FLOW menses is composed of: Blood from the ruptured capillaries Fragments of endometrial tissue Microscopic, atrophied, unfertilized ovum
Physiology of menstruation the cervix... 1 half of the cycle st Hormones decreased Mucus thick and scanty Poor sperm survival Ovulation Estrogen is increased Cervical mucus thin and copious Excellent sperm survival 2nd half Decreased progesterone level Mucus is thick Poor sperm survival
Hormones in the menstrual cycle
Pituitary gland Secretes FSH – starts the cycle
Pituitary gland Secretes FSH – starts the cycle FSH causes the ovary to develop an egg and release oestrogen
Pituitary gland Secretes FSH – starts the cycle Oestrogen inhibits production of FSH FSH causes the ovary to develop an egg and release oestrogen
Pituitary gland Secretes FSH – starts the cycle Oestrogen inhibits production of FSH Stimulates release of LH FSH causes the ovary to develop an egg and release oestrogen Lining of the uterus thickens
Pituitary gland Secretes FSH – starts the cycle Secretes LH Oestrogen inhibits production of FSH Stimulates release of LH FSH causes the ovary to develop an egg and release oestrogen Lining of the uterus thickens
Pituitary gland Secretes FSH – starts the cycle Secretes LH Oestrogen inhibits production of FSH Stimulates release of LH LH causes ovulation and releases progesterone FSH causes the ovary to develop an egg and release oestrogen Lining of the uterus thickens
Fertilization, Implantation & Development and Gestation
Fertilization the fusion of the sperm cell nucleus with the egg cell nucleus to produce a zygote (fertilized egg)
Fertilization: • External • Occurs outside of the body of the female • Increased number of eggs produced to insure the survival of the species • Ex) fish and amphibians
Fertilization: • • • • • Internal Occurs inside the body of the female Fewer number of eggs are produced Increased parental care insures species survival Ex) mammals, reptiles, birds
Fertilization: • fertilization in mammals occurs in the oviduct • The ova is viable for approximately 24 hours after ovulation
Implantation • After approximately a week, the developing embryo is implanted into the uterus • Embryo: conception to 8 weeks
Embryo: • a multicellular organism in the early stages of development 2 four cell stage embryos Eight cell stage embryo
Embryo: The beginning developmental processes are always the same in all animals: 1) cleavage 2) growth 3) differentiation
Embryo: • after fertilization the diploid ZYGOTE undergoes cleavage divisions in the oviduct
Cleavage the first series of cell divisions by mitosis after fertilization Cell division is rapid, new cells do not take time for the growth phase G1 cell growth does not occur so cells decrease in size with each cleavage division
• Morula forms (solid ball of cells) • Blastula forms (hollow ball of cells) • Cells begin to grow before dividing
Differentation • Gastrulation: one side of the blastula invaginates (indents) forming a gastrula • Three cell layers form
Differentiation • The changing of unspecialized embryonic cells into the specialized cells, tissues and organs of a multicellular animal
Germ Layers • Ectoderm Outer layer • Nervous system including brain, spinal cord and nerves • Lining of the mouth, nostrils, and anus • Epidermis of skin, sweat glands, hair, nails
Germ Layers • • • • • Mesoderm Middle Layer Bones and muscles Blood and blood vessels Reproductive and excretory systems Inner layer (dermis) of skin
Germ Layers • • • • • Endoderm Inner Layer Lining of digestive tract Lining of trachea, bronchi, and lungs Liver, pancreas Thyroid, parathyroid, thymus, urinary bladder
Placenta • organ that forms from the embryo and the uterus • contains blood vessels from the mother and the developing baby
Placenta • Oxygen & nutrients diffuse from the mother’s blood vessels into the baby’s blood vessels • Wastes diffuse from the baby’s blood vessels into the mother’s blood vessels
Umbilical Cord • two arteries and a vein Connects the fetus to the placenta
Amniotic Sac • Contains fluid (amniotic fluid) that protects fetus by giving it a stable environment and absorbing shock
• By the end of the 8th week of pregnancy the embryo is called a fetus and all of the major structures are present
Later Stages of Fetal Development
Human gestation • the period between fertilization and birth • approximately 3840 weeks
Teratogens • Substances that may harm the developing fetus and result in the formation of birth defects
Teratogens include: • Alcohol, certain drugs/medications, infections, and certain chemicals
Fetal Alcohol Syndrome Can result in mental retardation / learning disability Facial Features • Epicanthal folds • Small, widely spaced eyes • Flat midface • Short, upturned nose • Smooth, wide philtrum • Thin upper lip • Underdeveloped jaw
Cleft Lip / Palate • maternal alcohol consumption and maternal smoking during the early stages of pregnancy have been shown to increase the risk of developing orofacial clefts • http://www.hopeforkids.com/body_cleft_lip%5B1%5D.html#
How do twins form???
Monozygotic Twins (Identical Twins) • One egg is fertilized by one sperm • Embryo splits into two during the early stages of development • Have identical genes and must be of the same sex • (Incidence: about 3 in every 1000 births)
Dizygotic Twins (Fraternal Twins) • Two eggs are ovulated and each is fertilized by a sperm cell • No more genetically similar than any other sibling in the family (can be same/different sexes) • Maternal age, use of assisted reproductive technologies are factors • Incidence (6.7/1000 births in Japan to 40/1000 births in Nigeria)
LIST OF REFERENCES: Bhondwe, A., 2010, Human Reproductive System (Slide-share), viewed 06 March 2014, from http://www.slideshare.net/avinash15/human-reproductivesystem?qid=3d348044-a0b8-4ba6-a91071d505e688a6&v=qf1&b=&from_search=7 Bishop, S., 2014, Hormones in The Menstrual Cycle (Slide-share), viewed 07 March 2014, from http://www.slideshare.net/sbishop2/hormones-in-the-menstrualcycle-30343967?qid=1ddce368-24ed-4883-9a598328e935edbe&v=default&b=&from_search=10 Jardin. D. M., Anatomical Chart of Human Reproductive Systems (picture used), viewed and utilized on 09 March 2014, taken from http://www.flickr.com/photos/mdesjardin/4331654523/sizes/z/in/photostr eam/ Mehta, G., 2013, Gametogenesis (Slide-share), veiwed 07 March 2014, from http://www.slideshare.net/gunjan_rjt/gametogenesis16584337?qid=d7246b19-e486-4aa1-bf5639fed46875b8&v=qf1&b=&from_search=5 Rakiraks, Z., 2010, The Menstrual Cycle (Slides-hare), viewed 09 March 2014, from http://www.slideshare.net/rakiraksz/the-menstrual-cycle?qid=8528509e2a29-407b-bbde-8af437617f37&v=qf1&b=&from_search=5
Humanreproductivesystem the real deal. The Deal Real Estate... The real deal (1) The Real World - Agile. Making the deal real ge. Techorama 2014, the Real ...
1. The Real Deal Building Credibility andHow Authenticity Will Drive Sales Success David Parks VP of Business Development. 2. Credibility Authenticity Activity
1. Brainetics – The real deal . This article will hopefully dispel any worries you might have of aBrainetics scam . Brainetics is a legitimate product ...
1. Nose Magic Review-Scam or The Real Deal?I truly can not believe it up to the present that my nose changed a lot clipping Nose Magic.So this is my ...
1. Usana is the real deal USANA Health http://www.youtube.com/watch?v=naPCfSL65UM Sciences was founded in 1992 by Dr. Myron Wentz. He believes in the ...
Ebuzzing Social's case study of the Toyota GT86: The Real Deal campaign.
monthly reporting of community news in and around Greater Cleveland's African American neighborhoods.
The Deal Real Estate... The Deal is the leading property associates offering the best properties. We assure you the fullest satisfaction as regards to the ...