MENSTRUAL CYCLE:
BEGINS AT PUBERTY AND CONTINUES TO ABOUT LATE-40’S.
Has 4 Phases: FOLLICULAR, OVULATION, LUTEAL, MENSTRUATION
FOLLICULAR PHASE:
-Low estrogen levels cause the PITUITARY GLAND to secrete FSH (Follicle Stimulating Hormone) AND LSH (Leutenizing Stimulating Hormone)
** Egg DEVELOPS & MATURES in this stage (~ 10 DAYS)
OVULATION:* Shortest phase
* Occurs midway through cycle - Lasts 3-4 days
* Follicle ruptures & a mature egg is released into one of the FALLOPIAN TUBES.
LUTEAL PHASE:* Begins after egg is released & lasts about 10-14 days.
* Formation of the CORPUS LUTEUM (increases levels of ESTROGEN & PROGESTERONE)
* Uterine lining thickens
* Fertilization of egg GREATEST
MENSTRUATION PHASE:
* If not fertilized, egg passes through uterus w/in 2-3 days from ovulation
* Corpus Luteum disintegrates
* Estrogen levels drop, uterine linig detaches and along w/blood and the unfertilized egg is discharged through the vagina.
* Average period of menstruation lasts 3-7 DAYS
* New cycle begins w/first day of menstruation
* Continues in females until ~AGE 50 when follicles mature, rupture or disintegrate causing MENOPAUSE
4 PHASES OF MENSTRUAL CYCLE
Fertilization: Sperm
egg
* Process of a single sperm joining an egg usually while in the FALLOPIAN TUBE.
*Fertilized egg is called a ZYGOTE and has 46 CHROMOSOMES.
WHAT IS FERTILIZATION?
TWINS•FRATERNAL•2 separate eggs fertilized by 2 separate sperm.
•Boys, girls or one of each.
TWINS•IDENTICAL•1 egg fertilized by 1 sperm
•Splits after fertilization.
•Same sex.
FETAL DEVELOPMENT* zygote undergoes mitosis
* after 4 weeks zygote is called an EMBRYO
* AMNIOTIC SAC cushions and protects the developing embryo.
* PLACENTA- the connection between mother & embryo in which it receives its supply of nutrients & oxygen.
* END OF 8 WEEKS EMBRYO CALLED FETUS, umbilical cord begins to form.
* 9th month baby is called “Full Term”.
Full term baby is typically delivered vaginally.
Sometimes baby is delivered by Caesarian (C-section).
DISORDERSEctopic pregnancy- fertilized egg implants itself in fallopian tube, outside the uterus.
Cervical cancer - can be detected through a PAP SMEAR TEST.
Aids: caused by HIV, transmitted through body fluids (semen, vaginal fluid, blood)- no cure.