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57 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Hormonal Induction of Labour |
5 days
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Sperm Capacitation |
Further maturation sperm must undergo to be capable of fertilizing an egg - Occurs following ejaculation once sperm in female tract - Seminal fluids contains capacitation inhibiting factors |
Sperm changes to do something Occurs when? Seminal fluids contain? |
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After capacitation, sperm (2): |
1. Have increased rate of flagellate beat & accelerated motility pattern 2: Plasma membranes are more fragile (facilitates acrosome reaction) |
1. Increases… 2. Plasma membranes? |
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In Vitro Fertilization (IVF) can… |
Can induce capacitation by washing sperm or running them thru a Percoll gradient
- Where an egg is combined with a sperm in a laboratory dish |
Involves an egg and sperm |
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Acrosome Reaction |
- Binding of the sperm to receptors in the zona pellucida - This causes Ca++ levels to rise, triggering the release of acrosomal enzymes |
Binding of X to Y in Z This causes x lvls to rise |
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Zona Pellucida and Sperm |
The zona pellucida can bind many sperm, but only 1 sperm fertilizes the egg |
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Polyspermy |
The fertilization of an egg by more than one sperm |
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As soon as first sperm penetrates perivitelline membrane: |
1. Fast block to polyspermy 2. Slow block to polyspermy |
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Fast block to polyspermy |
Oocyte sperm-binding membrane receptors are shed (Oocyte membrane block) |
Membrane block |
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Slow block to polyspermy |
Increased Ca++ lvls trigger exocytosis of cortical granules. This hardens the zona pellucida and destroys its sperm-binding receptors |
Cortical reaction |
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After the sperm penetrates 2ndary Oocyte? |
Oocyte completes meiosis II, forming the polar body and the ovum. The swelling of the sperm and the ovum in the oocyte produces the female pro nucleus. |
Completes? Forms? |
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Sperm nuclei material form? |
Forms the male pronucleus; male and female pronucleus fuse to form 2n nucleus of zygote |
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Zygote |
Fertilized egg cell that results from a female gamete (egg) with a male gamete (sperm) Diploid |
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Developmental steps that occur while the embryo is traversing the fallopian tube (oviduct) (5 steps) |
1. Zygote (fertilized egg) 2. 4-cell stage (continue to duplicate) 3. Morula 4. Early blastocyst 5. Hatching |
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Developmental steps that occur while the embryo is traversing the fallopian tube: Step 3 Morula |
- occurs 72 (3 days) after fertilization - Embryo now consists of a loose collection of cells called the morula (a solid ball of cells) and continues down from the oviduct to the uterus |
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Developmental steps that occur while the embryo is traversing the fallopian tube: Step 4; Blastocyst |
Now the embryo consists of ~100 cells and the morula hollows out and fills with fluid - Occurs 4 days after fertilization |
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Developmental steps that occur while the embryo is traversing the fallopian tube: Step 5; Hatching |
The embryo looses its zone of Pellucida |
What happens to the zone of pellucida? |
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Implantation of the egg in lining of uterus: |
- Begins ~6 days following fertilization - Blastocyst burrows into endometrium (inner-lining of uterus) - Trophoblast cells grow out toward mat blood vessels; inner mast cells will give rise to embryo |
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Implantation of Blastocyst (5 steps from day 4-11) |
Day 4: Early blastocyst floats in uterine cavity and “hatches” from zona pellucida Day 6: Blastocyst adheres to uterine wall Day 7: Implantation begins as trophoblast invades uterine wall Day 9: Implantation continues; embryoblast has become a bolstered embryonic disc Day 11: Implantation complete; amniotic sac and yolk form |
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Germinal Period |
Conception to 2 weeks |
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Embryonic Period |
3 - 8 weeks after conception |
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Fetal Period |
9 weeks to term after conception |
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3 Embryonic Germ Layers |
Endoderm, ectoderm, and mesoderm |
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Endoderm |
Epithelial lining of GI and respiratory tracts |
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Ectoderm |
Gives rise to NS and skin |
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Mesoderm |
Gives rise to everything else not included in the ending/ectoderm during embryonic development |
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Placentation |
Formation of the placenta |
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Placentation: Blood supplies & what diffuses thru placenta? |
- Maternal and fetal blood supplies are NOT in direct contact - Nutrients, gases, and wastes diffuse thru: 1. Trophoblast layer 2. Mesenchyme layer 3. Fetal capillary endothelium |
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Umbilical cord (Arteries and vein?) |
- Usually 50-70 cm in length - Contains 2 umbilical arteries and 1 umbilical vein |
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Foremen Ovale |
Diverts blood from the right atrium to the left |
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Ductus venosus |
GI in baby is not a source of nutrition therefore bypasses the liver so it goes to other areas like developing heart and NS - Carries blood from the umbilical vein thru the liver into inferior vena cava |
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3 shunts in fetal circulation (foremen ovale, ductus venosus, and ductus arteriosus) |
Purpose of shunts is to bypass the lungs and liver because these organs will not work fully until after birth |
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Dual functions of the placenta: Endocrine |
Placenta secretes hCG from the beginning - Estrogen and progesterone of pregnancy mature more slowly - If placental hormones are inadequate when hCG lvls wane, the endometrium degenerates and pregnancy aborts |
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Dual placenta function: Exchange |
Nutrients and O2 diffuse into placenta while metabolic waste diffuses out |
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Human Chorionic Gonadotropin (hCG) |
Present in maternal serum by 8th day after fertilization; lvls peak by 60-80 days, then begin to decrease - Structurally similar to LH and can bind to LH receptors - Produced by placenta during pregnancy and stimulates CL to produce progesterone during pregnancy - Produced v early in pregnancy, peaks after 9 weeks and then goes down - hCG lvls can be detected after 3 days of missed period |
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Human placental lactogen (hPL) = Human chorionic somatomammotropin (hCS) |
- Structurally similar to GH and prolactin - Placenta begins to secrete hPL during 1st trimester; lvls increase until delivery |
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hPL function |
1. Stimulates breast development in preparation for postnatal lactation 2. Supports fetal bone growth 3. Makes glucose available to fetus by reducing insulin sensitivity |
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Estrogens and placenta |
- Initially come from CL; functionally assumed by placenta - Placenta converts circulating androgens to androgens - Initially estrone & estradiol-17-beta, then estriol (maintains uterine endometrium and contributes to breast development) |
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Progesterone |
Initially from CL; functionally gradually assumed by placenta - Lvls increase over course of the pregnancy - Has a relaxing effect on smooth muscles (see slide 17, lecture 4) |
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Influences of pregnancy on the Cardiovascular System (BP, BV, pulse, etc.) |
- BP decreases slowly to nadir @ 24 weeks; then slowly back up to NP - Pulse slowly increases to max of 15-2- beats/min above NP in 3rd trimester - Increased contractility and CO - Myocardial hypertrophy |
Nadir: Lowest point Myocardial hypertrophy: An increase in ventricular myocardial mass |
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Blood Volume During Pregnancy |
- Overall increase in BV (~40%): Plasma by ~45% & RBCs by 20-30&% |
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GI Tract During Pregnancy |
- Nausea: Increased progesterone, hCG - Hypermesis gravidarum: If untested can lead to dehydration, ketosis, electrolyte derangements, liver & kidney dmg |
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Urinary Tract During Pregnancy |
- Kidneys increase in length (increased renal blood flow) - Bladder tone decrease; bladder capacity nearly doubles - GFR increases in 1st trimester - High progesterone promotes renal Na (& water) loss; but increased aldosterone and estrogen promote salt and water retention - Increased risk of UTI due to retained urine |
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Cervix During Pregnancy |
Softening & increased vascularity from early 1st trimester Increased production of mucus by endocervical glands |
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Vagina during pregnancy |
- Cervical secretions increase in quantity - Decrease in pH (high estrogen) - Increased susceptibility to vaginal candidiasis (fungal infection, high estrogen, high glycogen) |
Vaginal candidiasis: Fungal infection |
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Uterus During Pregnancy |
- Enlarges by hypertrophy due to estrogen and progesterone - 2nd trimester: Uterus moves out of pelvis ad begins to displace intestines up - 36th week: Intestines are pushed up to just beneath diaphragm —> discomforts experienced by mothers include shortness of breath and constipation - 10x increase blood flow to uterus at term - Contracts every 5-20 min during later weeks of pregnancy |
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Prostaglandins |
- Important for labour and delivery - Hormones act close to where they’re produced - Comes from placenta - Stimulates uterine contractions |
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Stages of Parturition (3): |
1. Dilation: Uterine contractions dilate cervix up to 10c m (variable in duration) 2. Expulsion: Full d’isolation to birth (mins to hours) 3. Placental: Delivery of placenta; usually within 30 min after birth (all of placenta has to come out cause it is highly mitotic; can cause cancer) |
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Braxton Hicks Contractions |
Irregular contractions that are not coordinated due to rising lvls of estrogen (false contractions) |
Increasing lvls of estrogen interfere with progesterone’s ability to constrict uterus |
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Vitamin D during pregnancy |
Important for intestinal absorption for Ca |
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Vitamin K During Pregnancy |
Important in blood clotting |
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Folic Acid |
Helps prevent neuro tube defects |
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Important minerals during pregnancy: |
Iron: Helps increase RBC Calcium: Support development of skeleton of fetus; baby will take Ca of mother so need Ca in diet to maintain mother’s bone density |
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Parturition |
Labor and delivery |
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Oxytocin |
Responsible for stimulating labour contractions; most important hormone during labor and delivery - Produced in hypothalamus |
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Fetal Cortisol |
Important trigger for parturition and stimulates maturation of lungs in preparation for breathing air |
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When are estrogen lvls highest? |
Towards time of parturition |
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