SCIENCE

• Ovaries


  Female gonads that produce eggs and hormones
• Endometrium


  Lining of the uterus that thickens and renews itself, preparing for pregnancy
• Menstruation


  Woman's monthly bleeding, often called your "period"
• Puberty


  Time in life when a boy or a girl becomes sexually mature
• Follicle


  A fluid-filled sac that are found inside a woman's ovaries which contains an immature egg
• Feedback Mechanism


  A physiological loop that brings the body either toward or away from the normal, steady state
• Menstrual Cycle


  Period in the female's life wherein we have bleeding, coming from the shedding of the endometrial lining in response to the hormones produced by the ovary
• Menstrual Cycle


  • Regular changes in the activity of the ovaries and the endometrium that make reproduction possible
• Two Separate & Interconnected Cycles

  • Ovarian
  • Uterine
• Ovarian Cycle


  It focuses on producing the egg cell, development of egg cell until the follicle ruptures, and ovulation (release of mature ova from the dominant follicle)
• Uterine Cycle


  Thickening, shedding, and enhancing of the endometrial lining in response to the level of estrogen and progesterone in the body
• Menarche


  First occurrence of period
• Menopause


  Time when the ovulation stops
• Menstrual Cycle Periods


  • 1-7 days (menstruation, least fertile)
  • 8-9 (possible to conceive)
  • 10-14 OVULATION (the fertile window, best chance of conception)
  • 15-16 (possible to conceive)
  • 17-28 thickening of uterine lining (unlikely to conceive)
• Pre-ovulatory


  Prior to Ovulation
• Post-ovulatory


  After Ovulation
• Ovulation happens 14 days before the next cycle begins
• Pre-Ovulatory Period Phases

  1. Follicular (ovarian cycle) - focuses on the competition of the follicles to crown the dominant follicle, and the development of the egg cell to induce ovulation (2 weeks before ovulation)

  2. Hypothalamus and Pituitary gland are the mastermind of reproduction

  3. Pituitary hormones (LH and FSH) controls the maturation of the ovarian follicles

  4. Theca and Granulosa cells are hormone secreting cells of the ovary
• Follicular Phase (Days 1-10)

  1. Theca (LH RECEPTORS) = Androstenedione

  2. Granulosa (FSH receptors) = Aromatese

  3. Estrogen was secreted to bloodstream
• Follicular Phase (Days 10-14)

  1. There will be an increase of estrogen level in the bloodstream (NEGATIVE FEEDBACK TO PITUITARY GLAND)

  2. Dominant Follicle increases the secretion of ESTROGEN (POSITIVE FEEDBACK TO PITUITARY GLAND)
• Menstrual Phase (Days 1-5)


  Bleeding, shedding of the old endometrial lining (uterine cycle)
• Proliferative Phase (Days 6-12)

  The endometrial lining starts to thicken again due to the increase of the estrogen hormone (uterine cycle)
• Ovulation Phase (Days 13-15)


  The release of matured ova from the ovary to the site of fertilization
• During ovulation, the sac containing the mature ovum splits open releasing it from the ovary
• Luteal Phase (Days 15-22)

  1. The follicle ruptured is now known as Corpus Luteum (composed of luteinized granulosa and luteinized theca)

  2. It continues to produce hormones (androstenedione & aromatese) to produce 17B-estradiol also known as Estrogen

  3. Granulosa will now respond to P450scc - an enzyme that converts cholesterol into pregnenolone (a form of progesterone)

  4. Dominant Hormone - Progesterone

  5. The empty sac left in the ovary (Corpus Luteum) still produces both estrogen and progesterone

  6. High level of progesterone (NEGATIVE FEEDBACK TO THE PITUITARY GLAND) signals that ovulation has occurred
• Secretory Phase (Days 16-28)

  1. The endometrial lining is fully enhanced/thickened

  2. If no fertilization happens it will go back to the menstrual phase due to the sudden drop of estrogen and progesterone

  3. Uterine glands provide more mucus
• After Day 15, the fertilization window starts to close
• Days 22 - Day 1 of the Next Cycle

  1. Around this time the corpus luteum will slowly stop producing estrogen and progesterone as it turns to corpus albicans

  2. Blood vessels in the uterine wall contract and spasms due to the lack of estrogen and progesterone

  3. The uterine lining is shedding as menstrual blood beginning the first day of the new cycle
• Two Pituitary Hormones Needed to Facilitate Women's Menstrual Cycle

  • Follicle-stimulating Hormone (FSH)
  • Luteinizing Hormone(LH)
• Ovarian Cycle vs Menstrual Cycle

  Ovarian Cycle is only a part of menstrual cycle
• Women experience monthly cycles to procreate, a higher chance of pregnancy
• Reasons You Might Miss a Period

  • Pregnant
  • Body is still maturing
  • Stress
  • Approaching menopause
  • Exercising vigorously
  • Lost a ton of weight
  • Hormone disorder
  • Using prescription/street drugs
• Gestation/Pregnancy


  It starts from ovulation, fertilization, up to fetal development. A period of time between conception and birth.
• Stages of Human Development Before Birth

  1. Fertilization of the ovum - Mature oocytes meets with the sperm cell, Oocytes + Sperm cell = zygote, Meiosis and Meitosis to create plenty of cells

  2. Transforming zygote to blastocyst - Blastocyst is a turning embryo made up of about a hundred cells that reaches the uterine cavity within 5-6 days for implantation

  3. Embryonic Development - From implantation of the blastocyst to the endometrium up to the first 2 months of the pregnancy, the developing child is called embryo

  4. Fetal Development - During the third month of pregnancy, the developing embryo begins to look more human and is now called fetus
• First Trimester (0-12 weeks)

  1. 1 month - Formation of amniotic sac, Development of placenta, Formation of dark circle for eyes, Development of mouth, lower jaw, and throat, Blood cells developed and circulate, Beating of "tiny heart tube"

  2. 2 months - Continues development of facial features, Formation of arms, legs, toes, and eyes, A well-formed neural tube, Bones replace cartilages, Head is in large proportion than the body, Heartbeat can be heard

  3. 3 months - External ears, arms, hands, fingers, feet and toes are fully formed, Development of fingernails and toenails, Reproductive organs also develop, All the organs and limbs are present and will continue to develop
• At the end of the first trimester (12 weeks), all the body's major organs and structure have began to develop, the heart is beating regularly, fingers and toes have formed, the fetus is around 3 inches long and weighs nearly 1 ounce, the nerves and muscles work together, and the fetus can make a fist
• Second Trimester (16-28 weeks)

  1. 4 months - Audible heartbeat, Fingers and toes are well-defined, Hair forms on body and head - Lanugo, Facial features are obvious, Nervous system is starting to function, Reproductive organs and genitalia are now fully developed

  2. 5 months - Fetus are moving around, Fetus will develop muscles and will exercise them, Hair begins to grow on the head; lanugo will form, Skin is covered with a whitish coating called vernix caseosa

  3. 6 months - Finger and toe prints are visible, Skin is reddish in color, wrinkled and veins are visible through translucent skin, Eyelids begin to part and the eyes open (eyes not functional)
• Fetus at 4 months


  • Audible heartbeat
  • Fingers and toes are well-defined
  • Hair forms on body and head - Lanugo (protection of amniotic fluid)
  • Facial features are obvious
  • Nervous system is starting to function
  • Reproductive organs and genitalia are now fully developed. Penis and clitoris come in 1 cell thus gender misreadings
• Fetus at 5 months


  • Fetus are moving around (connection of nervous and circulatory)
  • Fetus will develop muscles and will exercise them
  • Hair begins to grow on the head; lanugo will form
  • Skin is covered with a whitish coating called vernix caseosa
• Fetus at 6 months


  • Finger and toe prints are visible
  • Skin is reddish in color, wrinkled and veins are visible through translucent skin
  • Eyelids begin to part and the eyes open. (eyes not functional)
  • Fetus responds to sounds by moving or increasing the pulse