Presentation on theme: "11.4.7 Outline the role of the epididymis, seminal vesicle and prostate gland in the production of semen."— Presentation transcript:
1Outline the role of the epididymis, seminal vesicle and prostate gland in the production of semen.
211.4.7 Sperm produced in seminiferous tubules In the epididymis, sperm are stored and gain motilityOn arousal, millions of sperm travel along the vas deferensNear the bladder, seminal vesicle glands add a large volume of fluid (high fructose concentration)Prostate adds more fluid (alkaline) to help spermatozoa survive female’s vagina
3Compare the processes of spermatogenesis and oogenesis, including the number of gametes and the timing of the formation and release of gametes
4How are the alike? Both begin with Both make use of Both include mitosisBoth make use ofLH and FSHBoth include2 meiotic reduction divisions
5How are they different? Development into sperm between puberty & death TImingDevelopment into sperm between puberty & deathDevelopment into eggs between puberty & menopauseLocationTestisOviductHaploid/Diploid4 haploid sperm cells1 haploid egg cell
6How are they different? Amount Millions of sperm are produced every dayTypically, one secondary oocyte is ovulated per mentrual cycleSizeVery smallVery largeReleaseDuring ejaculationSecondary oocyte released during ovulation
7Describe the process of fertilization, including the acrosome reaction, penetration of the egg membrane by a sperm and the cortical reaction
8Fertilization Not as simple as “sperm meets egg” How does the sperm get through the zona pellucida?What causes meiosis of the egg to finish?How does the egg prevent further entry of sperm cells (polyspermy)
1511.4.10 Outline the role of HCG in early pregnancy
16HCGWhen the blastocyst implants into the endometrium, it starts to release HCG hormone.
17HCGHCG concentration continues to rise for 8-10 weeks. HCG causes the corpus luteum to secrete estrogen & progesteroneProgesterone and estrogen inhibit FSH and LH – so no more eggs are released
18HCGProgesterone maintains the endometrium, where the blastocyst develops into a fetus and the placenta forms.
19HCGSecondary oocyte left an outer ring of follicle cells within the ovaryThis layer begins mitotically dividing & secretes estrogen and progesteroneThis is a temporary endocrine gland (corpus luteum)If no fertilization, the corpus luteum secretes progesterone for about 14 days
2011.4. 11 Outline early embryo development up to the implantation of the blastocyst.
21Early Embryonic Development Fertilization = zygoteStart mitotic division1st division usually 24 hours after fert.Dividing and still moving down the fallopian tube getting closer to the uterusApprox. 100 cells by the time it reaches the uterus (4 -5 days later)Ready to implant – a blastocyst
22Blastocyst Characterized by Surrounding layer of cells called the trophoblast (helps with the fetal portion of the placenta)A group of cells on the interior known as the inner cell mass and located toward one end of the “ball” (Inner cells become body of embryo)A fluid-filled cavity
23Explain how the structure and function of the placenta, including its hormonal role in secretion of estrogen and progesterone, maintain pregnancy
25HCG and the PlacentaLarge human ovum – contains nutrients needed for early development1st 2 weeks after fertilization – no true growth bc. embryo is still size of original eggNutrients used for metabolism, not growthWhen embryo implants into the endometrium it is running out of foodEmbryo & maternal endometrium begin to create the placenta
26Progestins Progesterone is a progestin with 2 major roles Support the endometrium – provide an environment conducive to fetal survival. If the endometrium is deprived of progestins, the pregancy will be terminatedSuppression of contractility in uterine smooth muscle.
27EstrogensStimulate growth of the myometrium and antagonize the myometrial-suppressing activity of progesterone.Stimulate mammary gland development.
2811.4.13 State that the fetus is supported and protected by the amniotic sac and amniotic fluid.
33Blood supply2 fetal blood vessels within the umbilical cord carry fetal blood to the placentaBlood within these 2 vessels is deoxygenated and carries waste productsFetal blood exchanges materials with the maternal bloodstream and another fetal blood vessel returns the blood to the fetusReturning blood is oxygenated and nutrients have been added while in the placenta
34Materials passed from fetus to mother within the placentaMaterials passed from mother to fetus within the placentaCarbon dioxideOxygenUreaNutrients (glucose, amino acids, etc)WaterHormones (e.g. HCG)HormonesVitamins, mineralsAlcohol, many drugs, nicotine (if taken by mother during pregnancySome viruses such as German measles, HIV (if mother is infected)
35Blood mixing?At NO TIME does the blood of the fetus and the blood of the mother actually mix – exchange of material only
36Outline the process of birth and its hormonal control, including the changes in progesterone and oxytocin levels and positive feedback
42Major events of vaginal childbirth Major hormone changesOpening of the cervix to 10 cmThe most typical position for the baby is head-first, face downThe shoulders of the baby are typically the widest part to pas through the birth canalThe afterbirth is the name for the expelled placenta, occurring after the baby is bornLactation begins soon after birth