Lecture 15: Fertilization and Pregnancy Flashcards
List 3 tests for pregnancy
1) Urine HCG
2) Serum HCG (qualitative, quantitative)
3) Transvaginal ultrasound
Describe Naegele’s Rule for Dating Pregnancy
-Onset of last menses
-Move back 3 months
-Then 7 days forward
-One year forward
What are the assumptions of Naegele’s rule for dating pregnancy?
28-day cycles with 14-day follicular phase and woman knows her LMP
Is Naegele’s rule for dating pregnancy accurate?
No; incredibly inaccurate- there are apps for this these days
1) How long does pregnancy last from gestation and from LMP?
2) Uterus expands more than ______ times in pregnancy
3) How much does the fetus develop in pregnancy?
4) What happen to the breasts in pregnancy?
1) Lasts about 38 weeks from conception (40 weeks from LMP)
2) 20
3) Fetus develops to the point of being able to leave maternal life support
4) Breasts enlarge and develop ability to produce milk
Define fertilization
Fusion of male and female gametes
What two things in the genital tract transport the gametes toward each other?
Cilia and Smooth Muscle
The _________________is the site of fertilization
Ampulla
1) Males produce _______mL of semen
2) _____________ million sperm per mL
3) Only _____________ sperm reach the ampulla
1) 2-6
2) 20-30
3) 50-100
1) Fertilization must occur within how many hours after ovulation?
2) Where does it normally occur?
3) How long can sperm live?
1) 12-24 hours
2) In ampulla,upper third of the oviduct
3) Up to 5 days
[Fertilization]
1) Define capacitation
2) What triggers it?
1) Final maturation of sperm
2) Acidic environment removes glycoproteins
[Fertilization]
1) Sperm binds to what?
2) What ion does this increase? What does this lead to?
1) Zona Pellucida
2) Ca2+; acrosomal reaction
(acrosome fuses w. plasma membrane)
[Fertilization]
1) What does Ca2+ trigger the acrosome to fuse with?
2) What does this trigger? What physical change does this cause?
1) Acrosome fuses with the plasma membrane
2) A cortical reaction; egg becomes hardened to other sperm
[Implantation]:
Zygote undergoes __[mitotic/ miotic]__ cell divisions, forming a ball of cells called a ________, and then a ____________ capable of implantation on the _____metrium
mitotic; morula; blastocyst; endometrium.
[Implantation]
1) What happens to a blastocyst’s surface after it’s formed?
2) What happens to the endometrium simultaneously? How?
1) Becomes sticky
2) Becomes adhesive; formation of CAMs [cell adhesion molecules]
[Implantation]
1) What do the cells in the blastocyst do [after blastocyst and endometrium become sticky/ adhesive]?
2) How do they do this?
3) Why/ what does this accomplish?
1) Digest pathways to endometrial cells.
2) Cords of trophoblastic cells dig into the endometrium, where they cont. to digest uterine cells.
3) Carves a hole to make space and provide fuel for developing embryo.
1) Following implantation of the blastocyst in the uterine wall, the _______________ forms.
2) What form and fill with blood to eventually develop into this structure?
1) placenta
2) Lacunae [eventually become a placenta]
What else continues while the placenta forms in the uterine wall?
[hint: this process is one word]
Differentiation
What 2 tissues of the endometrium develops into the placenta?
Trophoblastic and decidual
[Placenta development]
What layer of the endometrium is 2 layers thick and becomes called the chorion?
Trophoblastic layer
[Placenta development]
What layer of the chorion continues to expand? What does this eventually erode, and what does this cause?
Trophoblastic layer; maternal capillary walls, leaking maternal blood to fill the cavities
1) A system of what two interlocking tissues makes up the placenta?
2) True or false: All exchanges take place across this extremely thin barrier.
3) What systems of the mother does this allow the fetus to use?
1) Maternal (decidual) and fetal (chorionic) tissue
2) True
3) Respiratory, digestive, and renal
List 2 hormones made by the placenta and describe when each begins to rise and for how long
1) hCG: human chorionic gonadotropin
-detectable 6-8 days post-fertilization [doubles every 2-3 d until 15 wks]
2) hPL: Human placental lactogen
-rises in wk 3 [until term]
1) What hormone extends life of the corpus luteum?
2) What does this also stimulate?
3) When is this hormone detectible?
4) When does it increase and at what rate?
1) hCG
2) luteal steroidogenesis
3) 6-8 days after fertilization
4) Every 2-3 days until about 15 weeks
1) What hormone is similar to GH and PRL?
2) When does it rise in pregnancy?
3) What does it regulate? By promoting what?
4) What condition can it lead to?
1) hPL
2) During the 3rd week until term
3) Fuel availability by promoting maternal insulin resistance
4) Gestational diabetes
What else does the placenta make?
Peptides and some other hormones
What exchanges does the placenta facilitate?
Exchng. of gases, nutrients, and other factors.
Give examples of exchanges between the mother and fetus and list the direction of transfer.
1) To fetus: O2, water, electrolytes, carbs, lipids, amino acids, vitamins, hormones, antibodies, drugs (some), viruses (most)
2) To mother: CO2, water, urea, waste products, hormones