Lect 30

Question 1

pregnancy can be divided into what 4 stages

Answer 1

1. initiation
2. gestation
3. parturition
4. lactation

Question 2

site of fertilization

Answer 2

• oviduct
  
  • normally occurs in upper third (ampulla)

Question 3

fertilization must occur within what time frame after ovulation

Answer 3

24 hours

Question 4

how does female reproductive tract aid in sperm migration

Answer 4

• contraction of myometrium
• upward contraction of oviduct smooth muscle
• Allurin released by mature eggs
  
  • chemoattractant for sperm to reach egg in ampulla of oviduct

Question 5

upon sperm passage through female reproductive tract, process of what occurs

Answer 5

• capacitation: or activation
  
  • surface characteristics of sperm are altered
    
    • cholesterol withdrawal
    • surface prodteins redistributed
    • calcium influx -> increase motility

Question 6

sperm motility in the cervical canal requires what pH? What makes this pH

Answer 6

• alkaline
  
  • alkaline secretions from prostate gland
  • estrogen makes mucus water

Question 7

sperm transported is assisted by myometrial contractions. what is responsible for this

Answer 7

• prostaglandins in ejaculate
• estrogen-primed tissue

Question 8

capacitated sperm penetrate the corona radiata, contact the zona pellucida and undergo what reaction

Answer 8

acrosome reaction

Question 9

sperm contain receptors that bind to what protein that in turn triggers the acrosome reaction

Answer 9

ZP3 protein

Question 10

what is the acrosomal reaction

Answer 10

• acrosomal enzymes digest zona pellucida creating a pathway to the plasma membrane of the ovum

Question 11

sperm fusion to ovum’s membrane is mediated by

Answer 11

• binding of fertilin on sperm head to integrin receptor on ovum membrane -> zona reaction

Question 12

What is the zona reaction

Answer 12

• release of cortical granules containing enzymes that degrade ZP3 proteins and harden zona pelucida
  
  • prevent polyspermy
• signals ovum for completion of 2nd meiotic division

Question 13

formation of female pronucleus and male pronucleus is termed

Answer 13

fusion

Question 14

blastocyst is composed of what two cells

Answer 14

1. trophoblasts cells: become placenta
2. inner cell mass: become embryonic structure

Question 15

blastocyst implants in endometrial lining by means of enzymes released by

Answer 15

trophoblast

Question 16

Progesterone levels from corpus luteum peak 6-8 days from ovulation converting uterus to secretory gland. what is secreted? What effect does this have on optimal time for implantation

Answer 16

• glycogen and lipid required for implantation
• relaxes myometrium
• **due to progesterone action, days 20-24 of regular 28 days cycle are optimal period for implantation

Question 17

implantation of blastocyst occurs in what 3 stages

Answer 17

1. apposition
2. adhesion
3. invasion

Question 18

only after implantation is completed, is hCG detectable in maternal serum, 8-11 days after conception. what is its function

Answer 18

• hCG will rescue the corpus luteum at this time

Question 19

most ectopic pregnancies occur within the

Answer 19

fallopian tube

Question 20

placenta is well established and operational how long after implantation

Answer 20

5 weeks

Question 21

what is the organ of exchange between maternal and fetal blood that performs the functions of the digestive system, respiratory system and kidneys for the fetus

Answer 21

placenta

Question 22

what hormones does the placenta secrete

Answer 22

1. hCG: human chorionic gonadotropin
   
   1. maintains corpus luteum until placenta takes over function in last two trimesters
2. estrogen
3. progesterone

Question 23

function of hCG

Answer 23

• maintains pregnancy
• stimulates corpus luteum to secrete progesterone and estrogen
  
  • when the placenta secretes estrogen and progesterone, hCG levels decline and corpus luteum regresses
• what pregnancy tests detect

Question 24

when do levels of hCG peak

Answer 24

• levels peak between 9-12 weeks gestation

Question 25

What is the most important estrogen in pregnancy

Answer 25

Estriol

Question 26

estrogen during pregnancy requires what for synthesis

Answer 26

both fetus and placenta

Question 27

functions of estrogen during pregnancy

Answer 27

1. increased growth of myometrium - muscles for labor 2. development of ductile system of breasts 3. stimulates prolactin release by anterior pituitary 4. relax and soften pelvic ligaments 5. inhibits lactation

Question 28

sources of progesterone during pregnancy

Answer 28

* elevated throughout pregnancy * first 6-12 weeks -\> corpus luteum * after 12 weeks -\> placenta

Question 29

progesterone synthesis during pregnancy requires what

Answer 29

**maternal cholesterol**

Question 30

Progesterone function during pregnancy

Answer 30

1. conversion of uterus to secretory gland readying for implantation 2. formation of cervical plug 3. inhibition of myometrial contraction 4. inhibition of prostaglandin synthesis in uterus 5. development of alveolus and lobule in breast 6. inhibit lactose synthesize