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
List functions of estrogen during pregnancy
- Stimulate myometrium growth
- Enlarge breast & ductal system
- Stimulate secretion of prolactin but inhibit milk secreting action
- Prepare for labour by inc myometrial oxyticin receptors & myometrial gap junctions
- Prepare cervix for labor by induction of prostaglandins
List functions of progesterone during pregnancy
- Suppressing myometrium contraction so prevent abortion
- Nutrition & development of embryo as it inc secretion of uterine tube & uterus for zygote & affects cell cleavage in early development
- Progesterone promotes storage of nutrients in endometrial cells transforming them to decidual cells
- Prepare breast for lactation promote alveoli development
- Inhibit milk secreting action of prolcatin
- Form thick mucus plug & prevent contamination
Describe function of hSC
- Similar to GH, dec mother glucose utilization to be available for fetus & mobilizes fatty acids to provide alternative source of energy for fetus
- Similar to prolcatin it prepares mammary glands for lactation by by synthesis of enzymes needed for milk production
Mention function of each:
1. Relaxin
2. Placental PTHrp
- Soften cervix to prepare for parturation, loosens CT between pelvic bones
- Inc maternal plasma Ca++ for calcification of fetal bones & if needed causes localized dissolution of maternal bones
Intercourse must occur between……..for pregnancy to take place
One day before ovulation & one day after
List events which initiate parturation
High levels of estrogen induce:
1. Inc myometrial gap junctions, inc prostaglandins, inc conc of myometrial receptors for oxytocin
2. Inc uterine responsiveness to ordinary, low level circulating oxytocin
3. Strong coordinated contractions in uterus
4. Initiate onset of labour when myometrial responsiveness reaches critical threshold (100 times greater at full term than in non-pregnant)
Oxytocin causes uterine contraction by:
- Direct action on uterine muscles
- Inc production PGE2 which enhances uterine contractions
Involution of uterus is caused by……& facilitated by……..
Thus, in breast feeding women it takes……but……in non-breast feeding women
Dec levels of estrogen & progesterone/oxytocin
6 wks/ 4 wks
Mention hormones which develop mammary glands & role of each during pregnancy
- Placental estrogen: duct development
- Placental progesterone: alveolar development
- Prolactin & somatomammotrophin: synthesis of enzymes needed for milk production
Lactation is initiated……after delivery due to…..
1-3 days
Due to abrupt decrease in the circulating estrogen & progesterone that removes inhibitory effect on prolactin action
List permissive hormones to lactation
Cortisol, inuslin, PTH, GH
Rate of milk secretion dec within…….
7-9 months
Secretion of…..can be condition but…..couldn’t be.
Oxytocin
Prolactin
Describe events that take place to mammary gland during weaning
. Dec in prolactin release, thus dec milk secretion
2, dec oxytocin release thus dec milk ejection, milk acculumates in alveoli, presses alveolar epithelial cells & inhibits milk production by mechanical compression
List adv of breast feeding for baby
- Provide immue cells & antibodies protect against infection
- Factors that may stimulate development of infant’s immune capabilities
- Factors that promote maturation of digestive system so that it is less vulnerable to diarrhea
List adv of breast feeding for mother
- Helps involution of uterus
- Prevent pregnancy as it inc prolactin which inhibits GnRH, LH, FSH, prevent ovulation & pregnancy
Women who do not breastfeed can have a cycle…..after delivery but for those who breastfeed it is after…..
6 wks
6 months
