Reproduction & Development RQ 1.How many sperm can a mature man make in a day? 2.Normally, how many mature eggs does a females ovaries release over her life? 3.Through what process are gametes produced? 4.How many days after fertilization does the baby blastocyst implant in the uterine wall? 5.What hormone does the embryo secrete telling the moms body that shes pregnant? 1. What are the two functions of the male reproductive system? 1.Production of sperm 2.Delivery of sperm to the female 2. Where do sperm form and what are the associated structures that help transport them? Sperm are made in the testes, which are housed by the scrotum (which needs to stay cool for sperm production) Maturation of sperm after meiosis takes about 74 days (can make 300 million sperm every day) Epididymis tubes where the sperm mature Vas deferens sperm hang out here for 2 3 months until they go to the urethra Seminal vesicles secrete sugar-rich fluids for the sperm for energy Prostate gland secretes an alkaline fluid for the sperm to move & survive Bulbourethral glands secrete fluid that will neutralize the females acidic environment ALL of this stuff together = semen 3. What happens to males during puberty? Which hormones are specifically involved? Puberty = development of secondary sex characteristics for sexual maturity The hypothalamus tells the pituitary to secrete FSH and LH FSH will stimulate the production of sperm cells LH will cause testosterone production Testosterone causes the growth & maintenance of the sex organs, increases body hair, muscle mass, and bone length, and deepens the voice 4. Briefly describe the basic parts of the female reproductive system. Functions to produce eggs, to receive sperm, and provide an environment for an embryo to grow and develop Ovaries allow for egg maturation Oviducts tube for egg transport from the ovary to the uterus Uterus muscular organ where the baby develops Cervix narrow opening out the uterus into the vagina (how the baby leaves) 5. What happens to females during puberty? The hypothalamus tells the pituitary to secrete FSH and LH FSH stimulates the development of follicles in the ovary A follicle is a group of epithelial cells that surround a developing egg FSH causes the ovaries to release estrogen Estrogen causes the development of the secondary sex characteristics in females Growth & maintenance of sex organs, growth of bones & broadening of hips, body hair, fat deposits, and of course the menstrual cycle 6. How are eggs produced and released? When a female is born, she already has 2 million potential eggs (primary oocytes) that have stopped development at Prophase 1 of meiosis Most of these will break down, and at puberty the ovaries only 40,000 Once a month several of these oocytes finish meiosis and one egg ruptures out of the ovary (ovulation) and passes into the oviduct About 400 eggs will be ovulated over the course of a females life 7. Briefly overview the flow, follicular, and luteal phases of the menstrual cycle. Menstrual cycle the series of changes that occur to produce an egg and prepare the uterus for a baby Repeats about once a month The corpus luteum (the part of the follicle left from the egg being released) secretes progesterone and estrogen Progesterone maintains the lining of the uterus in preparation for fertilized egg implantation Continued (using a 28 day cycle) Flow phase: Day 1-5 The lining of the uterus (the endometrium) passes out of the uterus through the cervix Contractions (cramps) help expel this stuff Follicular phase: Day A developing primary oocyte secretes estrogen which repairs the endometrium Estrogen levels peak, and LH causes ovulation Luteal phase: Day 15 28 Named for the corpus luteum, which produces estrogen and progesterone which thickens the endometrial lining in prep for a zygote If no fertilization, back to the flow phase If implantation, endometrium begins nourishment 8. Describe the process of fertilization and implantation of an egg. Released egg only stays alive for 24 hours sperm (can live for 48 hours) must be present in the oviduct in those first hours of ovulation for fertilization to occur 300 to 500 million sperm are delivered, but most die because of the acidic female environment Only a few hundred make it to the oviducts Once a sperm gets to the egg, the egg membrane changes electric charge, preventing other sperm from fertilizing Continued Egg nucleus + sperm nucleus = fertilized egg (zygote) This zygote continues to the uterus, undergoing mitosis as it goes After 6 days the zygote gets to the uterus, and is now a hollow ball of cells called a blastocyst When this attaches to the uterine lining, it has implanted 9. List and describe the purpose of the various embryonic membranes. Amnion: filled with amniotic fluid Shock absorber and temperature regulation Allantois: outgrowth of the digestive tract Blood vessels from this form the umbilical cord which attaches the embryo to the uterine wall Chorion: outer membrane (surrounds amnion) 12 days after fertilization, chorionic villi begin to grow into the uterine wall These two together form the placenta 10. What structures allow the exchange of materials between embryo and mom? The placenta deliver nutrients and carries wastes away from the embryo Maternal blood vessels lie very close to the embryos chorionic villi, allowing the diffusion of these nutrients from mom and wastes from baby across the placenta, which is connected by the umbilical cord The waste products are excreted by the mom 11. How is a pregnancy maintained? 1.the developing zygote implants 2.it starts to secrete hCG (human chorionic gonadotropin) 3.which keeps the corpus luteum alive & secreting progesterone 4.which in turn maintains the endometrial lining 5.Until the 3 rd or 4 th month when the placenta takes over 12. What are the three different processes of fetal development? 1.Growth the actual increase in the number of cells 2.Development as these cells move and arrange themselves into specific organs 3.Cellular differentiation these cells begin to perform specific tasks and functions 13. What happens during the first trimester? A woman may not know she is pregnant The embryo is very sensitive to outside influences Drugs, environmental influences, malnourishment All the organ systems are formed by the 8 th week and is now a fetus At the end of this trimester, the baby is 28 grams (1 ounce) and 7.5cm (3 inches) from head to butt Gender can be determined 14. What happens during the second trimester? 4 th month is mostly limited to fetal body growth 5 th month mom can feel the fetus 6 th month eyes are open & lashes form Baby could possibly survive outside of the womb with lots of medical intervention At the end of this trimester the baby is 650 grams (22 ounces) and 34cm (13 inches) long 15. What happens during the third trimester? Mass of fetus more than triples Kid is kicking, stretching, and moving freely 8 th month fat is deposited beneath the skin in preparation for newborn insulation Babys systems are developed and can now survive outside of the uterus By the end of this trimester, the baby is on average 3300 grams (7 pounds) and 51cm (20 inches) long 16. How can genetic disorders be predicted? Genetic counseling Will use medical histories of the parents and families (pedigrees) Biochemical analyses of bloodwork Karyotypes DNA analysis 17. What is the first stage of birth? Describe how this happens. (Oww) Dilation of the cervix Mild contractions are stimulated by the baby pushing on the cervix This causes the release of the hormone oxytocin The contractions open (dilate) the cervix to allow the baby to leave the uterus Dilation needs to get to 10cm (4 inches) Contractions get closer together and intensify Usually the amniotic sac will rupture (water breaking) 18. What happens during the expulsion stage? The cervix is fully dilated The uterine contractions get so strong that the baby is forced out of the uterus, through the cervix, and into the birth canal The moms abdominal muscles contract with the uterus, pushing even stronger This stage USUALLY lasts 20 minutes to an hour 19. What is the placental stage of birth? Happens 10 15 minutes after the baby is born The placenta separates from the uterine wall and all membranes are released from the moms body (afterbirth) Uterine muscles keep contracting, constricting the uterine blood vessels to mom doesnt excessively bleed You might not want to see this 20. Which hormone regulates growth? How does it do this? Human growth hormone (hGH) is secreted by the pituitary Acts on all cells, but mostly on the skeleton and skeletal muscles Works by increasing the rate of protein synthesis and fat metabolism Thyroxin, estrogen, and testosterone help too 21. What changes occur during infancy? First two years of life Lots of growth 2x birth weight by 5 months old 3x birth weight by 12 months old 4x birth weight by 24 months old Increase in physical coordination Learns to roll, sit, crawl, and walk Increase in mental development Begins to speak 22. What happens as someone grows from child to adult? Childhood- period from infancy to puberty Relatively steady growth Develops ability to reason and solve problems Adolescence- from puberty till max growth Growth spurts are typical 5-8cm in one year for some teenage boys Maximum height is achieved Determined by heredity, nutrition and environment Organs have reached maximum mass 23. What kinds of stuff happens to your body as you get older? Metabolism and digestion are slower Skin loses some elasticity Less pigment is produced (gray hair) Bones become thinner and more brittle Vertebral disks get compressed (shorter) Vision and hearing diminish Some people stay just as smart and active as always!