Hormone Cycles

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Hormone Cycles
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Pg. 394 Male
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Hypothalamus releases GnRHGnRH causes the
pituitary to release

• Male FSH which
• Acts on sperm producing cells
• Nurse cells (Sertoli) release peptide hormone
  which slows/prevents FSH production

• Male LH which
• Acts on interstitial cells to produce
  testosterone which increases sperm production
• High levels of testosterone decrease GnRH output
• This slows the release of LH

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Pg. 398 Female
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• FSH is secreted by the pituitary gland(day1)-
  menstruation starts
• About 1000 follicles in the ovary start to
  develop but only one matures (goes through
  oogenesis)
• The developing follicle secretes estrogen
• Estrogen causes 1) the uterine lining to thicken
  with mucus and blood vessels 2) secondary sex
  traits Lasts 10-14 days
• High levels of estrogen in the blood cause 3) the
  pituitary gland to stop releasing FSH (Negative
  feedback)

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1. Now the pituitary starts secreting LH
2. LH levels (when high) cause 1) ovulation about
   day 14
3. LH causes 2) the ruptured follicle to fill with
   cells and fluid forming a yellow body called the
   corpus luteum
4. The corpus luteum secretes progesterone which
   1) maintains the lining of the uterus (pregnancy
   hormone). It also 2) prevents new follicles from
   developing by inhibiting the release of FSH
   Lasts 10 to 14 days

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1. if the egg is not fertilized, secretion of LH
   stops as the corpus luteum breaks down and the
   level of progesterone drops
2. the lining of the uterus is shed
3. As menstruation begins the levels of estrogen
   and progesterone are at their lowest so the
   pituitary starts to secrete FSH so back to Day 1.
   ?

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• Cowpers Gland mucus and fluids which help
  protect the sperm from acids cleanses the
  urethra
• Seminal vesicles produce fructose for energy to
  fuel the mitochondria of the sperm
• Prostate Gland produces an alkaline buffer to
  neutralize the strong acid vagina

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