Pregnancy Flashcards
What is fertalization?
- Union of a sperm and egg
- Ovulated egg is viable for 12-24 hours
- Sperm can survive up to 7 days, but average 3-4 days
- Capacitation
- Final maturation process of sperm in the female
- Requires female molecules
- Makes the head fragile and allows for acrosomal reaction
- Final maturation process of sperm in the female
What is acrosomal reaction?
- . Acrosomal reaction is the first stage of fertalization
- Release of enzymes from the acrosome functioning to degrade the outside layers of the egg
- Ganulosa cells cells left from follicle
- Zona pellucida tough layer of sugars and proteins
- 50% of sperm will release all enzymes before reaching zona pellicuda
What are the second, third, and fourth stage of fertilization?
- Cortical Reaction
- Prevention of polyspermy (fertilization by more than one sperm)
- Causes proteins in remaining zona pellucida to crosslink and become impenetrable
- Results in fertilization membrane
- Other sperm are rejected
If two sperm fertilized one egg, how many chromosomes would be present in the zygote?
A. 46
B. 23
C. 69
D. 92
A. 46
What is implantation?
- After fertilization, cells undergo mitosis
- Group of cells (~100) called blastocyst
- Attaches to the endometrium after 6 days of fertilization
- Cells will differentiate into different structure
- Some will become the embryo
- Some will become the placenta
- Some will become the fetal membranes (amniotic sac)
What is the placenta?
- Organ responsible for diffusion of nutrients and waste between fetus and mother
- Maternal blood from uterine vessels will fill sinuses around fetal capillaries(chorionic villus)
- Maternal and fetal blood do not mix during development
- Also produce progesterone and estrogen as pregnancy continues
- Contributes to high levels of both hormones during pregnancy
What does hormones have to do with pregnancy?
- Fertilized egg secretes hormone human chorionic gonadotropin (HCG)
- Detected as earlier as 8 or 9 days after fertilization
- HCG stimulates the corpus luteum so that it does not degrade
- Placenta will eventual take over progesterone production
- This occurs at about 12 weeks
- Progesterone is important to maintain endometrium
- Estrogen levels rise 30x above regular levels
- Stimulates fetal tissue growth
- Stimulates maternal tissue growth (uterus, breasts)
- Makes pelvis joints more flexible
If HCG levels are high, what other hormone would also have a high level?
A. GnRH
B. LH
C. Progesterone
D. FSH
What happens to the Female Physiology during pregnancy?
- Increase in weight
- Increase in metabolic rate
- Healthy weight gain of ~25 pounds
- Increase in blood volume
- Placenta requires about 600mL from mother
- Results in a 30% increase in volume
- Glomerular filtration rate increases 50% results in elevated urine output
- Other symptoms
- Swollen feet pressure on vessels decreases venous return
- Heartburn pressure on stomach
- Frequent urination pressure on bladder
- Stretch marks tearing of proteins in the skin as it grows
- Morning sickness cause still unknown
What are the three stages of labor?
- Dilation
- 8-24 hours
- Pressure of baby on cervix triggers release of oxytocin from the posterior pituitary
- Causes contractions
- Fetal membranes usually break, releasing fluid
- Expulsion
- 1 hour
- Baby’s head enters vagina
- Placental
- Final contractions expel placental and other membranes
Initial pressure of the baby’s head on the cervix causes the release of oxytocin. Oxytocin results in contractions, increasing the pressure of the baby’s head on the cervix and causing more oxytocin to be released. This is a ______________.
Negative feedback loop
Positive feedback loop
What is a Caesarean Section?
- Incision through skin, fat, and muscle (abdominal and uterine) to remove the baby
- Can be planned or emergency
- Some women can have a vaginal birth after C-section
