Gestation, Partiration, Lactation Flashcards
Period of gestation from conception is…..& from last period is…..
38 wks
40 wks
Fertilization takes place in……, the ovum remains viable for…..
Upper 3rd of fallopian tube
12-24 hrs
Mention factors that enhnce sperm transport,
- Thin watery cervical mucus secreted 2-3 days before under effect of estrogen
- Reverse peristaltic contractions of uterus & oviducts by prostaglandins & estrogen
- Ova release attarcting chemical to sperms
GR: High number of sperms are needed for male fertility
- Very small % of sperm can reach ovum
- Acrosomal enzymes of many sperms are needed to penetrate oval barrier
Describe process of fertilization
- Sperm penetrate ova by membrane-bound enzyme
- Sperm via fertilin bind with specific receptors on surface of ZP that triggers acrosomal reaction that digest ZP. Thus only sperm of same species bind to ZP receptors & pass through
- First sperm to reach ovum fuses with plasma membrane of ovum, head of sperm penetrates ovum cytoplasm, that triggers 2nd meiotic divison & forms zygote , also inhibits ZP receptors & harden it to prevent polyspermy
Implantation of fertilized ovum place is….& time is…..
Dorsal wall of uterus
1 week after fertilization
Mention parts of placenta & their origin
- Fetal part: tropholblastic tissue that is modified into chorionic tissue
- Maternal: endometrial cells modified into decidual tissue
Placenta starts functioning at……, & becomes full functioning at…..
5 wks
10 wks
Describe functions of placenta
- Function as digestive, respiratory & excretory organ
- Acts as protective barrier to prevent rejection by mother immune system
- Temporary endocrine organ secretes hCG, estrogen, progesterone, hCS, relaxin, PTHrp
Describe function of hCG
- It maintains corpus luteum of pregnancy
- Stimulates secretion of testosterone by Leydig cells
- Stimulates CTZ in vomiting center responsible for morning sickness
Describe functions of corpus luteum of pregnnacy
- Secretes large amounts of estrogen & progesterone until placenta becomes able to secrete high amounts
- Secretes rekaxin that relaxes symphsis pubis & dilates cervix
- It partially regresses (slowly involutes) after 3-4 mon of gestation. But does not convert to scar tissue till after delivery.
Describe rate of hCG secretion
Inc rapidly in 1st month, peaks in 2nd month, decline in 10th wk this low pevel is maintained till end of pregnancy.
HCG is found in blood at…..and in urine at…..
6 days
14 days
Describe synthesis of placental estrogen
- Placenta converts cholesterol to pregnenolone
- Fetal adrenal cortex converts it to DHEA
- Placenta converts it to estriol
What is significance of measuring estriol level.
Used clinically to assess fetal vitality