Female Reproductive System

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Female Reproductive System
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Basic Anatomy

• Ovary (gonads)
• Follicles containing oocytes (immature egg cells)
• Corpus luteum
• Fallopian Tubes
• Pathway from ovary to uterus site of ideal
  fertilization
• Uterus
• Destination for fertilized egg to implant and be
  sustained
• Vagina
• Entry for sperm
• Exit for baby

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Basic Anatomy The Brain

• Pituitary Gland
• Releases Hormones
• Hypothalamus
• Tests blood levels for various hormones and
  decides what should come next sends signals to
  pituitary

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Basic Hormones

• FSH - Follicle Stimulating Hormone
• Secreted by the pituitary gland (both male and
  female)
• Stimulates the follicle to form and grow (effect
  in female)
• LH - Lutenizing Hormone
• Secreted by the pituitary gland (both male and
  female)
• Causes ovulation (release of a mature egg) and
  causes the corpus luteum to form (effect in
  female)
• GnRH - Gonadotropin Releasing Hormone
• Secreted by the hypothalamus (at the base of the
  brain next to the pituitary gland) (both male and
  female)
• Causes the pituitary gland to increase production
  of FSH (both male and female)

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Cows Head
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Follicle Stage

• Days 5-13
• Increased FSH levels cause
• Follicle to enlarge
• Follicle to produce more estrogen

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Follicle Stage (cont)

• Increased estrogen levels cause
• endometrium to thicken
• hypothalamus (brain) to tell pituitary (also
  brain) to release more FSH and LH

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Ovulation

• Around day 12-15
• Peak levels of FSH and LH cause
• Follicle to rupture
• Egg is released into fallopian tube (about the
  diameter of a human hair)
• Egg has 24 hours to be fertilized or it will die

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Luteal Stage

• Days 16-29
• Peak of lutenizing hormone stimulates corpus
  luteum (Latin for yellow body) to form from empty
  follicle

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Luteal Stage (cont)

• Corpus luteum secretes some estrogen and, as it
  grows, increasing amounts of progesterone cause
• Endometrium wall to thicken
• FSH and LH drop to see if pregnancy occurs (takes
  6-7 days for zygote to travel and implant)

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Basic Hormones (cont.)

• Estrogen
• Secreted by the follicle and the corpus luteum
• Causes the outer lining of the uterus
  (endometrium) to thicken
• Progesterone
• Secreted by the corpus luteum
• Causes the outer lining of the uterus
  (endometrium) to thicken
• HCG - Human Chorionic Gonaditropin
• Secreted by the implanted embryo
• Causes progesterone levels to stay high and
  maintain a thickened uterine wall
• Levels are detected by pregnancy tests if it is
  there, then there is a pregnancy (no false
  positive but can get a false negative)

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Pregnancy?

• If pregnancy occurs
• Embryo implants and placenta starts releasing HCG
  so moms body knows its pregnant
• Initially, mom maintains progesterone and
  estrogen after month 3, baby does it on its own
• This keeps endometrium wall thick and
• Prevents hypothalamus from secreting GnRH which
  prevents the pituitary from producing FSH and
  starting all over.

James at 1 week old
Isabella at 1 week old
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Menstrual Phase

• If no implantation has occurred
• Corpus luteum breaks down
• Progesterone drops
• Days 1-5
• Endometrium breaks down and is expelled
• Hypothalamus detects low progesterone and
  estrogen and release GnRH
• Pituitary releases FSH..

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Summary of Events
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What do birth control pills do?

• There are several different brands but the main
  categories work in one of two ways
• Keep estrogen at artificially high levels
  simulating levels during pregnancy.
• This stops the hypothalamus and therefore the
  pituitary from starting the cycle over and
  releasing an egg
• No egg no chance for pregnancy
• (1/100 chance 99 accuracy!)
• Use progestin alone or with estrogen
• Progestin makes it difficult for implantation to
  occur and for sperm to travel to the fallopian
  tubes.
• Note progestin is a synthetic version of
  progesterone and is similar in how it works
• After 21 or so days, the hormones stop (placebo
  or no pill) and the body prepares for the next
  cycle by menstruating

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