Parts to the System PARTS AND FUNCTIONS: In Scrotum – Testes – produce sperm in tightly coiled tubes: Seminiferous Tubules - meiosis – Interstitial Cells – in between seminiferous tubules: produce TESTOSTERONE – Epididymis – stores maturing sperm Tubes – Vas Deferens – carries sperm from epididymis to urethra. – Urethra – in penis. Exit point for sperm Food and Travel - – Seminal Vesicles – releases “sugars” – Prostate Gland – releases alkaline solution – Cowper’s Gland – fluid to lubricate urethra, flush out urine Hormones: – GnRH stimulates production of FSH and LH(ICSH)
HORMONES and NEGATIVE FEEDBACK GnRH stimulates the pituitary to release LH and FSH LH stimulates the production of testosterone. FSH works on “sartoli’ cells to provide nourishment for sperm. Sartoli cells produce a hormone “inhibin” which inhibits the pituitary and hypothalamus resulting in lower levels of FSH HIGH LEVELS OF TESTOSTERONE PRODUCES NEGATIVE FEEDBACK ON THE PITUITARY GLAND DECREASING LEVELS OF LH (ICRH).
Parts and Functions Parts and Functions: – Ovaries –eggs produced in cavities: FOLLICLES. Released at Ovulation. – Oviduct – passageway for egg. SITE of fertilization – Uterus – muscular, pear shaped. Holds developing organism – Cervix – lower end of uterus – Vagina – entry point for sperm. Exit point for Fetus. Birth Canal.
General: Hormones from Glands control cycle: – Hypothalamus(in brain): GnRH…….secreted to Pituitary: FSH – – Stimulates growth of egg – Stimulates secretion of estrogen LH – – Stimulates ovulation – Stimulates empty follicle to convert to corpus luteum – Stimulates corpus luteum to secrete estrogen and progesterone – Ovary Estrogen – Stimulates repair and growth of the uterus Progesterone – Stimulates and maintains growth of the uterine lining
Stages of Menstruation Menstruation – (5 days) – Egg not fertilized – Inner Uterine lining (endometrium) breaks down and passes out of the vagina(with the egg). Follicle Stage – (9 days) – FSH production increases – Follicles in ovaries develop. (oocyte) – Estrogen secreted to heal, repair, and thicken endometrium with blood vessels Ovulation – Middle of Cycle--- 1 day – High level of estrogen decreases FSH and stimulates secretion of LH – High level of LH – Follicle ruptures and egg is released. Corpus Luteum Stage – ( 13 days) – Corpus Luteum is produced in ruptured follicle…stimulates progesterone production. – Maintains endometrial growth. – Egg implantation if fertilization takes place
Hormones: – and + feedback ESTROGEN – Negative feedback on pituitary to block FSH release. – Positive feedback on pituitary to signal release of LH Progesterone – Negative feedback to block FSH release – Negative feedback to block LH release
Copulation vs. Fertilization Copulation – – Coupling – Physical contact between male and female needed for sperm to move from male to female: intercourse Fertilization – Fusion of male and female nuclei to produce a zygote
After Fertilization MALE AND FEMALE GAMETES LINE UP AT THE EQUATOR PREPARE FOR 1ST MITOTIC DIVISION NO CELL GROWTH “CLEAVAGE DIVISION” AFTER SEVERAL DIVISIONS: – BALL OF CELLS = MORULA REACHES UTERUS IN APPX. 4 DAYS Implantation – into wall of the endometrium
Parturition Prostglandin – hormone- like substances; help to stimulate contractions. Oxytocin – hormone – released by pituitary gland POSITIVE FEEDBACK SYSTEM Parturition – process of delivering the fetus and placenta. Includes – Labour – dilation of cervix, vagina – Expulsion – Birth – Afterbirth – delivery of placenta
Amniocentesis and CVSAmniocentesis –•inserting a needleinto the uterusthrough a verysmall incision inthe abdomen• needle takesamniotic fluid –contains embryoniccells.• used to detectgenetic defects
In vitro fertilization Approximately 1 of 6 couples Used mainly as a way to overcome a female infertility (physiological) issue: blocked oviducts or timely ovulation Cannot be used in the case of low sperm count.
IVF Process1. Drug given to stop menstrual cycle.2. Large doses of FSH given – 2 weeks3. HCG given 48 hours before collection – matures eggs4. Man provides semen.5. Eggs extracted through the vagina6. Each egg is mixed with some sperm in a petri dish – incubated 24 hours7. Check to see if fertilized!8. Embryo’s selected and placed in uterus9. Wait approximately 2 to 3 weeks and take pregnancy test – implantation10. Scan as normal for any developmental issues
Ethical Issues of IVFPro: Against: Environmental infertility Fate of extra embryos? will not affect offspring Long term storage of Not developed – no pain embryos – stem cells? to embryo Multi pregnancy places Genetic screening before stress on family transferring Expensive Parents have strong High rate of failure desire for child religious
Permanent Contraception – Female sterilization (tubal ligation) – Vasectomy Mechanical – Diaphragm – Intra Uterine Device – Condom Chemical – Spermicide – Birth control pill* – “day-after” pill* Other – Rhythm - cycle – Withdrawal before ejaculation – Abortion
Birth Control and “Day After” Pill Birth Control – synthetic estrogens and progesterone(s) that prevent release of GnRH ---- FSH & LH Morning After – – Blocks progesterone receptors in uterus. – altering the lining of the womb, so a fertilized egg cant embed itself there.
Ethics of Family Planning and ContraceptionPro Against Can choose to get Most not 100% pregnant effective A few methods 100% Promotes promiscuity effective Abstinence difficult in Population control marriage Irreversible
Puberty in Males Marked by a sharp increase in testosterone production: Production of sperm: primary!! Secondary: Enlargement of penis and testes Growth of body hair: face, underarm, pubic Deepening of voice Broad shoulders - muscle
Puberty in Females Marked by the onset of the menstrual cycle Egg production: primary! Secondary: – Breast Development – Body curve – placement of tissue – Hair: underarm, pubic
Developmental Terms to Know Zygote – newly fertilized egg Cleavage – first series of cell divisions; multiple rounds of mitosis Morula – 4-16 cells; solid ball of cells Blastomere – cells of the morula Blastocyst – after 5 days; develops a hollow cavity Implantation – blastocyst penetrates endometrium Endometrium – uterine lining Gestation – pregnancy, 40 weeks
Implantation Blastocyst contains fluid filled cavity called blastocoel. Blastocyst: – Two parts: – Inner mass cells - will develop into the embryo – Trophoblast – releases HCG hormone; digests a hole into the endometrium HCG helps to maintain progesterone levels during pregnancy. Pregnancy test.