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Unformatted text preview: Clicker Question The sperm fertilizes the “egg” in the _________. A) vagina B) ovary C) uterus D) Fallopian tube E) small intestine Where are we? Last Last time we saw a movie on reproductive biology as part of the theme: I am my genes. genes. This This time I will discuss the anatomy and physiology of the male and female reproductive systems. systems. Next Next time I will discuss how we develop into males, females or intersexuals. intersexuals. Thomas Sanchez: Disputationes de Sancti Matrimonii Sacramento This This book (1602-1754), written by a (1602Jesuit priest, describes the whole sexual life of men and women, clearly and concisely in the coldest scientific language. Sanchez describes what is lawful, what is venial sin and what is a mortal sin. It It was a controversial book about a controversial subject and some editions were placed on the Index of Prohibited Books. Havelock Ellis (1927) “In this particular field the evil of ignorance is magnified by our efforts to suppress that which never can be suppressed, though in the effort of suppression it may become perverted.” Robert Latou Dickinson (1949) “When the time comes that diagrams and descriptions of the normal functions of these universal organs are as generally accessible and as much taken for granted as are pictures of other life processes, we shall doubtless wonder at our artificially fostered mystifications and many of our elaborately manufactured attitudes of shame, and not yet lose our feeling that privacy for intimacy is good taste….” Robert Latou Dickinson (1949) “We in medicine, are called upon to do our part…to integrate within a workable code of ethics a sane science of sex.” sane There There will be disagreement among us in Bio G 1110 in terms of what constitutes a workable code of ethics and a sane science of sex. 1 The Cell: The Basic Unit of Life and a Commodity Our Our generation has taught you that everything can be given a price and to a large degree something’s value is determined by its price. Perhaps we know the price of everything and the value of the price of everything and the value of nothing. nothing. Does Does selling _____ for money give life more value or corrupt the value of life because _____ belongs in a higher sphere of valuation than does money? Fill Fill in the blanks: genes, hormones, sperm, eggs, kidneys and other organs, children. The The Egg as a Commodity? elitefertility.com www.health.state.ny.us eggdonor.com www.aperfectmatch.com www.ivf.org www.drary.com www.eggdonorcornell.com selling eggs infertile banned 2 Sperm as a Commodity? Genius Sperm Bank Video Sperm Bank Video "..it’s helping to expand my shoe collection...." http://www.freevials.com/ http://www.thespermbankofca.org/dcp.html http://www.gayspermbank.com/ Whose Responsibility is the Baby Conceived with a Purchased Sperm? In In September 2009, the state Appeals Court refused to get involved in a mother’s efforts to force a Newton, MA sperm bank to reveal reveal the identity of her twin daughters’ father so she can sue him for child support. The The “father” was a young medical student who sold his sperm with the agreement his identity would be held “in strictest confidence.” technology legal gaps leave embryos in limbo The Free Enterprise System Helps Infertile People and Same Sex Couples to Have Babies Ex ovo omnia (“All from the egg”) (“All Using Using a magnifying glass to view the development of chicken eggs, William Harvey (1651) proposed that all animals, including humans originate from eggs. This This went against his hero Aristotle because it precluded the spontaneous spontaneous generation of animals from mud or excrement. Harvey Harvey then went on to conclude that the semen played only a semen marginal marginal role in the development of the baby. 3 William Harvey (1651) Exercitationes de Generatione Animalium William Harvey: A Field Theory of Pregnancy When When Harvey dissected animals after copulation, including rabbits, dogs and the does kept for venison by his friend, King Charles I, he never found any semen in he the uterus the uterus. He He could not find a material cause for material pregnancy. He concluded that there was no no need to mix the fluids that came from a man and a women and that a woman is made pregnant by a man in a nonmaterial nonmaterial way— way—like the way a piece of iron is magnetized by a magnet. He also said that the uterus conceives an embryo just as a brain conceives an idea. Late Late 1600s: Anatomists look for smaller things In In the late 1600s anatomists used the newlynewlyinvented microscope to look for structures inside the organs and fluids. This led to the discovery of the follicle, which was mistaken for an egg, and to follicle the the discovery of sperm. The The discovery of the “egg” led to the idea that the egg contained a preformed miniature copy of the preformed baby and that the semen just “activated” it. semen The The later discovery of sperm led to the idea that sperm the sperm contained a preformed miniature copy preformed of the baby and the egg just “nourished” it. The Ovarian Follicle is a Multicellular Structure Containing the Primary Oocyte. It is not an Egg. Oocyte. Ultrasound Image of Follicle in Ovary Use of the New Technology of Microscopes Led to Two Theories of Preformation Ovist Ovist, Ovulist The egg The egg contains a preformed preformed miniature copy of the baby and the semen just activates it semen just “activates” it. Spermist Spermist, Animaliculist, Homunculist The sperm The sperm contains a preformed preformed miniature copy of the baby and the egg egg just “nourishes” it. 4 Reinier de Graaf—Ovist Graaf— Reinier Reinier de Graaf was the first person to describe follicles in the follicles ovary, which he called ovar “the female testicles”. He He deduced that the follicle follicle contained an ovum or ovum or egg from observing an ectopic ectopic pregnancy. Pathway of “Egg” Reinier Reinier de Graaf dissected female rabbits at various times after breeding and discovered changes in the ovaries. He He discovered follicles in the in ovaries and believed that the follicles were eggs until he found structures in the uterus that were even smaller than the follicles. He He also discovered that the “egg” traveled through the Fallopian tubes on its journey from the ovary to the uterus. The Ovist’s Party Line From From these observations, de Graaf and the other ovists believed that: The egg The egg contains an entire human in miniature and semen only stimulates its growth. All All characteristics are thus inherited from the mother. inherited With With the invention of the microscope, soon after de Graaf’s death, sperm were discovered. The The role of the male in the formation of the baby was rereevaluated by scientists who would come to be known as “spermists”. Spermists Leeuwenhoek believed he could see muscles and nerves in the sperm and said, "I know very well that there ll th th are Universities who do not believe that living creatures are in the male semen; but I do not mind about this, as I know I have the truth." Antonie van Leeuwenhoek was a SelfSelf-Experimenter “What I am observing is a natural consequence consequence of conjugal coitus... and not just an artifact of sinfully defiling myself….” 5 "At position Q, I discovered discovered a few little animals from the semen... From these observations we could see very clearly that it is not clearly that it is not the the vagina but the uterus (womb) which is created to receive the semen.." The “Spermists” Thought that they could See Little People in the Sperm Mr. Dalen Patius Published these Pictures of Sperm Spermists Spermists Niklaas Hartsoeker (1694) believed that if he had a better microscope, he would be able to see the preformed baby inside the sperm. Antony van Leeuwenhoek (1699) The Spermist’s Party Line Spermists Spermists believed that: The mother The mother serves as an incubator and nourishes the baby that is already inside the baby sperm (the homunculus). All All characteristics are inherited from the father. At At this point, the ovists and spermists were fighting each other; then Pierre-Louis Moreau Pierrede Maupertuis came along with the synthetic theory. "I have in fact imagined that I could say as I beheld the have in fact imagined that could say as beheld the animalcules animalcules in the semen of an animal that there lies the head and there as well the shoulders and there the hips; but since these notions have not the slightest shred of certainty, I will not yet put forward such a claim, but hope that we may have the good fortune to find an animal whose male seed will be so large that we will recognize within it the figure of the creature from which it came." 6 Maupertuis’ thinking is like that of Albert Szent-Gyorgyi’s: Szent“Discovery “Discovery consists of looking at the same thing as thinking something everyone else and thinking something different.” Albert Szent-Gyorgyi (1962) Szent (1962) Apology: Sometimes biologists get carried away with a new technology (like the invention of the microscope) and forget or discount the obvious common sense thoughtful observations. thoughtful Maupertuis: The Observation “If a black man marries a white woman, it would seem that the two colors were mixed and that their child is a mulatto with features partially resembling those of his father and of his mother.” The New Way of Thinking “There “There are…potent reasons pointing towards an equal contribution by each sex. The child is born sometimes with the father’s features and sometimes with the mother’s.” mother’s.” “If the fetus were just the vermicule swimming in the seminal fluid of the father, why would he at times resemble the mother? If he were nothing but the mother’s egg, what would his face have in common with his father’s?” Maupertuis (1753): Sperm and Egg Contain Particles [Genes] that Determine the Form of Each Part “If there are, in each of the seminal seeds, particles predetermined to form particles the heart, the head, the entrails, the arms and the legs if these particular arms and the legs, if these particular particles particles had a special attraction for those which are to be their immediate neighbors in the animal body, this would lead to the formation of the fetus. Even though the fetus were a thousand times more complex, if the process above were exact, it would still be formed.” Anatomists of the 17th and 18th Century Regnier de Graaf, Adrian Spigel, William Hunter, Spigel, William Hunter, William Smellie dissected the bodies of women who died while they were pregnant. Female Reproductive System 7 All the primary oocytes a woman will have are formed before she is born. Primary oocyte Secondary oocyte Egg Egg Formation of the First Polar Body (Usually Takes Place Inside Follicle) Ovulation Secondary oocyte ↑ 8 Secondary Oocyte Enters the Fallopian Tube (Oviduct) Fimbriae Fimbriae recognize protein in extracellular matrix of the secondary oocyte. oocyte. Fimbriae sweep the Fimbriae sweep the secondary secondary oocyte into the Fallopian tube. Peristaltic Peristaltic motion and cilia cilia sweep the egg, zygote → 16-celled embryo down 6the Fallopian tube to the uterus. Cilia along the Fallopian Tube Sweep the Secondary Oocyte-Zygote-Embryo to the Uterus Oocyte-Zygote- Nicotine from smoking inhibits the cilia in the Fallopian tubes and increases the risk of an ectopic pregnancy. Ovary, Fallopian Tube and Uterus Male Reproductive System Human Testis and Prostate The testicles “testify the person to be a man.” 9 The Pathway of the Sperm The The sperm is made in the seminiferous tubules in the seminiferous testes testes. It It passes into the epididymis where it is stored. epididymis During ejaculation, it travels down the vas deferens During ejaculation, it travels down the vas deferens. The The contents (fructose) of the seminal vesicles are seminal added to form the semen in the ejaculatory duct. ejaculatory The prostate The prostate gland secretes bicarbonate and the bicarbonate bulbourethral bulbourethral glands secrete mucus and bicarbonate bicarbonate that that protects the sperm in the acidic vagina. acidic The The two ejaculatory ducts, each coming from one of the two testes join to form the urethra. urethra Exocrine Glands Help Make the Semen The seminal The seminal vesicles are are exocrine glands that secrete fructose into the ejaculatory ducts ejaculatory ducts. The prostate and The prostate and bulbourethral bulbourethral glands are exocrine glands that secrete bicarbonate and mucus into the urethra. Increasing Blood Flow into the Penis Stimulation of the parasympathetic parasympathetic nervous system results in the results in the production production of nitric oxide (NO), which (NO) causes a dilation of dilation the cavernous arteries in the penis. in Penile Tumescence The NO-induced dilation NOof the cavernous arteries results in an increase in blood to the corpus corpus cavernosum which is the which erectile tissue. The corpus il Th corpus cavernosum swells. The swelling causes a constriction constriction of the veins that lead blood out of the penis. All of these processes lead to an erection erection. Unexpected Erections Led to an Accidental Discovery In In 1985, Simon Campbell and David Roberts of Pfizer were looking for a drug that could treat angina (heart pain). Angina could be treated by relaxing the relaxing smooth muscles around the coronary arteries. coronary NO causes the relaxation of smooth muscle by NO causes the relaxation of smooth muscle by producing producing cyclic GMP (cGMP). Phosphodiesterase Phosphodiesterase is an enzyme that catabolizes (breaks down) cGMP. cGMP. So So Pfizer looked for drugs that would inhibit phosphodiesterase in the coronary arteries. Unexpectedly Unexpectedly, the men treated with the phosphodiesterase inhibitor UK-92480 got erections. UKerections 10 An Accidental Discovery There There are many kinds of phosphodiesterases in the body and each one has has a different sensitivity to drugs. While UKWhile UK-92480 was ineffective in inhibiting the phosphodiesterases in the coronary arteries (PDE-3), it was very effective in inhibiting the (PDEphosphodiesterase in the cavernous arteries of the penis (PDE-5). cavernous (PDEThe The inhibition of PDE-5 causes a relaxation of the smooth muscle of PDErelaxation the cavernous arteries and an increase of blood flow into the penis. UKUK-92480 became a treatment for erectile dysfunction (ED) called Viagra. Levitra and Cialis work the same way as Viagra does. www.viagra.com www.levitra.com www.cialis.com howstuffworks.com Intercourse: The Penis Enters the Vagina A Sex Manual from the 17th -19th Centuries online text The Female Reproductive System Meets the Male During Intercourse—Note da Vinci Thought that Semen Comes from the Man’s Brain through a Channel in the Spine Image of the Female Reproductive System During Intercourse: The Female Reproductive System Meets a Penis-Shaped Glass Tube Woman → ← Man Leonardo da Vinci 1493 The Copulation Copyright ©1999 BMJ Publishing Group Ltd. 11 The Female Reproductive Systems Meets a Real Penis (in an MRI of all places)—The Penis is Shaped Like a Boomerang Movement of Sperm and Ejaculation Stimulation of the sympathetic sympathetic nervous system of the male results in the contraction of muscles in the walls of the epididymis, epididymis, the vas deferens, the seminal vesicles and the prostate gland. Two sphincters also sp contract, one, at the base of the bladder which prevents urine flow and another at the base of the penis that prevents the movement of the semen into the urethra. Ejaculation occurs when Ejaculation occurs muscles along the penis contract and the sphincter at the base of the penis relaxes. Woman → ← Man Man Schultz, W. W. et al. BMJ 1999;319:1596-1600 Mature Sperm Swimming Sperm Female Reproductive System Ovary, Fallopian Tubes, Uterus, Vagina and Vaginal View of Cervix 12 Vaginal Symbiotic Ecology The The pH of the vaginal fluid is 3.5-4.5 and 3.5is due to the presence of lactic acid. lactic The The lactic acid is produced by species of the acid-loving bacterial complex, acidLactobacillus acidophilus, Lactobacillus acidophilus, which normally live in the vagina. The The lactic acid acts as an antimicrobial antimicrobial agent and kills the pathogens that cause and many sexually-transmitted diseases. sexuallyThe The low pH kills sperm, but the semen contains enough bicarbonate buffer to neutralize neutralize the acidity of the vaginal fluid. Cervical Mucus The sperm swim through the vagina along the strands of cervical cervical mucus that keep them away from the acid that that occurs along the vaginal walls. Before ovulation, the mucus is thin and it is easy for the sperm to swim through it. After ovulation, it becomes thicker and harder for the sperm to swim through it. Contractions of the uterus Contractions cervix propel the sperm to the Fallopian tubes. In the Fallopian Tube Egg Secondary oocyte 50 50 out of 200,000,000 sperm reach the secondary oocyte. oocyte. Sperm Sperm binds to a secondary oocyte and secretes digestive enzymes by exocytosis to break though the outer exocytosis to break though the outer layer layer of the secondary oocyte known as the zona pellucida. zona Fertilization Fertilization takes place within the Fallopian tube, approximately 24 24 hours after ovulation. The secondary The secondary oocyte, triggered by the sperm, undergoes the final meiotic division to form the egg. egg Fertilization: Boy Meets Girl Once Once fertilized, the zona zona pellucida or fertilization envelope of the egg becomes impermeable. Genetic Genetic material in nucleus nucleus moves from sperm into egg. from sperm into egg Mitochondria Mitochondria of sperm broken down in egg so that mitochondrial mitochondrial DNA is inherited only only from mother. After After fertilization, cells divide every 12-18 hours. 12After 5After 5-6 days, a blastocyst is blastocyst formed. Zygote with Two Pronuclei 13 Two Pronuclei Fuse Into One 2-Celled Embryo 4- and 8-Celled Embryo 8- Blastocyst Blastocyst “Hatches” from Zona Pellucida when it Enters the Uterus In the Uterus The The outer layer of the blastocyst, known as the trophoblast trophoblast secretes enzymes that allow the blastocyst to implant in the uterine lining, also called the endometrium. endometrium The inner The inner cell mass will give rise to the baby. 14 In the Uterus Pregnancy The The chorion secretes a hormone (human chorionic gonadotropin, hCG) that causes the ovary to secrete progesterone, which in turn progesterone causes the uterus to remain soft so causes the uterus to remain soft so the the embryo can implant. Pregnancy Pregnancy tests detect the presence of hCG in the urine. Blocking Blocking the action of progesterone with RU486 (Mifepristone) and RU486 (Mifepristone) Misoprostol (prostaglandin), prevents the embryo from implantation (pregnancy). 7 days after fertilization, the blastocyst implants in the days blastocyst endometrium endometrium. The trophoblast The trophoblast cells form the chorion, the embryonic chorion portion of the placenta. placenta Other Other Uses of Human Chorionic Gonadotropin: Manny Being Manny Manny Manny Ramirez ingested human human chorionic gonadotropin (hCG). hCG). Manny’s Manny’s batting average increased from .312 to .380. hCG hCG is used legally as a fertility treatment for men and women. Athletes Athletes coming off steroids use it illegally to regain their natural testosterone levels. While While Manny claims that his doctor prescribed it to him, hCG is banned by Major League Baseball. How How Fraternal (two(two-egg) Twins, Identical (one egg) (one-egg) Twins Twins and Conjoined Twins Are Formed Conjoined Twins: Abby and Brittany Hensel http://www.twinstuff.com/conjoined.htm Joined for Life The Twins that Share a Body 15 Embryonic Stem Cells The inner The inner cell mass gives rise to the: Future Future embry...
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