Topic 11: Human Health and Physiology 11.4 Reproduction

11.4.1 Annotate a light micrograph of testis tissue to show the location and function of interstitial cells (Leydig cells) germinal epithelial cells, developing spermatozoa and Sertoli cells http://www.indigo.com/software/gphpcd/his89-92.html

11.4.1 Annotate a light micrograph of testis tissue to show the location and function of interstitial cells (Leydig cells) germinal epithelial cells, developing spermatozoa and Sertoli cells

11.4.2 Outline the process involved in spermatogenesis within the testis, including mitosis, cell growth, the two divisions of meiosis and cell differentiation Spematogenesis – the process of making sperm Mitosis ,meiosis I and meiosis II are involved Meiosis I is stimulated by FSH Meiosis II is stimulated by testosterone After meiosis I, there are two spermatocytes with homologous pairs of chromosomes After meiosis II, there are four haploid spermatids The last step, differentiation, converts the spermatocytes into mature spermatozoa This stage is stimulated by testosterone http://wps.aw.com/bc_martini_eap_4/40/10469/2680298.cw/content/index.html

11.4.3 State the role of LH, testosterone, and FSH in spermatogenesis There are three hormones that play a role in spermatogenesis: Follicle stimulating hormone – produced in the pituitary gland FSH – stimulates sperm production in the seminiferous tubules and stimulates division and maturation of the Sertoli cells Lutenizing hormone – produced in the pituitary gland LH – Stimulates the interstitial cells (Leydig cells) to produce testosterone Testosterone – produced in the Leydig cells of the testis Testosterone – promotes spermiogenesis (the maturation of spermatids into spermatozoa) billboardmama.com

11.4.4 Annotate a diagram of the ovary to show the location and function germinal epithelial, primary follicles, mature follicle and secondary oocyte Ovulation caught on film: http://www.youtube.com/watch?v=2-VKgdhfNpY

11.4.4 Annotate a diagram of the ovary to show the location and function germinal epithelial, primary follicles, mature follicle and secondary oocyte

11.4.5 Outline the process in oogenesis within the ovary, including mitosis, cell growth, the two divisions of meiosis, the unequal division of the cytoplasm and the degeneration of the polar body Oogenesis – The production of a mature egg (ovum) begins in the ovaries of the female fetus before birth, but the final development of oocytes is completed in adult life Mitosis produces the germ cell which will later mature into a primary oocyte (2n) Meiosis I occurs creating a secondary oocyte and a polar body (haploid) The polar body is smaller than the oocyte (unequal division)

11.4.5 Outline the process in oogenesis within the ovary, including mitosis, cell growth, the two divisions of meiosis, the unequal division of the cytoplasm and the degeneration of the polar body Meiosis II then occurs resulting in three polar bodies and an ootid Meiosis II does not occur until after fertilization The three polar bodies are smaller than the ootid (unequal division) Ootid later differentiates into an ovum and the polar bodies degenerate

11.4.6 Draw and label a diagram of a mature sperm and egg inquisitr.com fainaboxvifici.blogspot.com

11.4.6 Draw and label a diagram of a mature sperm and egg The great sperm race http://www.youtube.com/watch?v=gAnMymnJiLM

11.4.6 Draw and label a diagram of a mature sperm and egg ouhsc.edu click4biology.info

11.4.6 Draw and label a diagram of a mature sperm and egg http://sciencevideos.wordpress.com/ahl/11-human-physiology-ahl/reproduction-ahl/

11.4.7 Outline the role of the epididymis, seminal vesicles, and prostate gland in the production of semen Semen consists of: Sperm Fluid from the prostate Fluid from the seminal vessicles Sperm cells are produced in the seminiferous tubules and later pass to the very-coiled epididymis where maturation is completed (this is where the sperm become mobile) Sperm are transported from the male to the female in a nutritive fluid (semen) secreted by the prostate glands and glands in the seminiferous tubules. The semen provides the sperm with fructose (high energy) The semen is also slightly alkaline which will neutralize the acidic environment of the vagina Seminal vesicles add nutrients that include fructose sugar for respiration Also adds mucus to protect sperm in the cell The Great Sperm Race Part II: http://www.youtube.com/watch?v=CNOLEQwKlF4&feature=related

11.4.8 Compare the process of spermatogenesis and oogenesis, including the number of gametes and the timing of the formation and release of gametes One gamete is formed per germ cell (plus polar bodies) Four gametes are formed per each germ cell Gamete is released once a month Form continuously Gametes can be released any time Spermatogenesis Formed in the embryo before birth Oogenesis All develop into mature gamete Meiosis I is completed but meiosis II only goes until prophase II and then finishes fertilization Formed from the time of puberty throughout life Form once a month Meiosis I and II go to completion during spermatogenesis

11.4.8 Compare the process of spermatogenesis and oogenesis, including the number of gametes and the timing of the formation and release of gametes

11.4.9 Describe the process of fertilization, including the acrosome reaction, penetration of the egg membrane by a sperm and the cortical reaction Fertilization is the fusion of male and female gametes Occurs internally in mammals in the upper part of the oviduct Step 1: The sperm passes between the cells of the follicle Step 2: When the sperm reaches the jelly coat the head releases hydrolitic enzymes (acrosome reaction) Step 3: Sperm and egg bind . See animation at: http://bcs.whfreeman.com/thelifewire/content/chp43/4301s.swf http://www.bio.davidson.edu/Courses/Molbio/MolStudents/spring2005/Champaloux/fertilization.jpg

11.4.9 Describe the process of fertilization, including the acrosome reaction, penetration of the egg membrane by a sperm and the cortical reaction Steps 4 and 5: The sperm reaches the plasma membrane of the secondary oocyte and the head of the sperm is engulfed by the plasma membrane of the secondary oocyte Step 6: Cortical granules are exocytosed by the oocyte and create a barrier to disallow the entry of another sperm (called the cortical reaction) These series of events stimulates the completion of meiosis II in the nucleus of the secondary oocyte Step 7: The haploid male nucleus and haploid female nucleus come together to form the diploid nucleus of the zygote . http://www.bio.davidson.edu/Courses/Molbio/MolStudents/spring2005/Champaloux/fertilization.jpg

11.4.9 Describe the process of fertilization, including the acrosome reaction, penetration of the egg membrane by a sperm and the cortical reaction Plat the “Great Sperm Race” Game at http://www.channel4.com/programmes/the-great-sperm-race/articles/the-great- sperm-race-game Great Sperm Race Part III: http://www.youtube.com/watch?v=ndrBCeqOqW0&feature=related Great Sperm Race Part IV: http://www.youtube.com/watch?v=kvAm99AGbrA&feature=related Great Sperm Race Part V: http://www.youtube.com/watch?v=VlSLt_uMExk&feature=related

11.4.10 Outline the role of HCG in early pregnancy The outer cells of the newly formed blastocyst secrete human chorionic gonadotrophin (HCG). This hormone keeps the corpus luteum “alive” so it will continue to produce progesterone, which in turn maintains the endometrium Eventually, the placenta will produce progetserone and the corpus luteum is no longer needed Also, progesterone inhibits the production of LH and FSH. This will inhibit ovulation . ehd.org

11.4.11 Outline the early embryo development up to the implantation of the blastocyst Fertilization occurs in the upper oviduct and the zygote is transferred down the oviduct by ciliary action Mitosis and cell division begin in a process called cleavage. Develops into a morula When the embryo reaches the uterus it is a mass of tiny cells called blastomeres Further division occurs and the blastomeres arrange themselves and form a blastocyst At about seven days after fertilization the blastocyst (consisting of about 100 cells) implants itself onto the endometrium The blastocyst will grow trophoblastic villi which absorb nutrients from the endometrium (before the placenta has developed)

11.4.12 Explain how the structure and functions of the placenta, including its hormonal role in its secretion of estrogen and progesterone, maintain pregnancy siumed.edu

11.4.12 Explain how the structure and functions of the placenta, including its hormonal role in its secretion of estrogen and progesterone, maintain pregnancy The function of the placenta is to exchange material between the mother’s blood and the fetus’ blood, but it is also an endocrine gland Early in pregnancy, progesterone is produced by the corpus luteum This role is later taken over by the placenta Progesterone: reduces contractions to maintain pregnancy reduces the effectiveness of the mother's immune system to prevent the production of antibodies against the baby When progesterone levels drop lactation begins Estrogen: results in an increase in size of the muscles of the uterus stimulates the development of the mammary glands

11.4.14 State that materials are exchanged between the maternal and fetal blood in the placenta It is a disc shaped structure composed of both maternal endometrial tissue and fetal membrane tissue At this location, the maternal and fetal blood are brought very close to each other over a large surface area – but they do not mix The exchange that occurs across the placenta is by both diffusion and active transport

11.4.14 State that materials are exchanged between the maternal and fetal blood in the placenta The following exchanges occur: respiratory gases – O2 diffuses across the membrane from maternal hemoglobin to fetal hemoglobin and CO2 diffuses in the opposite direction water – by osmosis glucose – facilitated diffusion amino acids and ions – active transport excretory waste products – urea antibodies – freely cross the membrane for protection (passive immunity) The placenta is a barrier to bacteria

• This protects the baby from mechanical harm 11.4.13 State that the fetus is supported and protected by the amniotic sac and amniotic fluid The fetus is wrapped in a sac (amniotic sac) which is filled with fluid (amniotic fluid) • This protects the baby from mechanical harm • Also protects the fetus from infections dna-laboratories.com

11.4.15 Outline the process of birth and its hormonal control, including the changes in progesterone and oxytocin levels and positive feedback At about week 38, progesterone levels drop and contractions of the uterus begin The babies head pushes against the cervix This causes stretching of the cervix and stimulates stretch sensitive nerve receptors These receptors send a signal to the brain which results in the release of oxytocin from the posterior lobe of the pituitary gland Oxytocin relaxes the fibers that hold the pelvis together and also causes stronger and more powerful contractions The cervix stretches even further sending more signals to brain, thus releasing more oxytocin (positive feedback loop) Eventually the baby is born, the cervix is not stretched anymore and the loop is turned off