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.