female endicrinology

• Hormone overview

  • What are they? chemicals released by 1 or more cells that affects cells nearby
  • Where are they? often released into blood stream
• Hormone overview

  How do they do it? 'lock and key'- target cells carry receptors -> cause regulatory changes within cells -> Androgens
• Autocrine


  Affects same cell - secretes hormone, leaves cell, binds to receptor
• Paracrine


  Effects nearby cells
• Endocrine


  To affect elsewhere in the body - secreted by glands into bloodstream
• Exocrine


  Secrete hormone via ducts into external environment - e.g. salivary, sweat, mammary glands
• Tropic


  Targets other endocrine glands - TSH simulating Thyroid, Hypothalamus affecting Anterior Pituitary
• Sex


  Target reproductive tissue -> oestrogen, progesterone, LH, FSH, Testosterone
• Anabolic


  Stimulate anabolic processes in specific cells
• Chemical classification

  • Steroid hormones= Oestrogen, Progesterone, Testosterone
• chemical classification 2

  nonsteroid hormones= Glycoproteins (FSH, LH, TSH), Proteins (GH, Prolactin), Peptides (Oxytocin, GRnH), Amino Acids (Adrenaline, noradrenaline)
• Repro cycles:

  2 important= Ovarian + Endometrial
• Ovarian cycle summary:

  Produce ovum at regular intervals
• Endometrial cycle summary:

  Create environment for implantation
• Gonadotrophic Cycle: 


  Anterior pituitary secretes Gonadotrophins (GN) -> FSH stimulates follicle -> LH releases ovum -> Hypothalamus controls AntPit's action= GnRH released into the blood vessles around AntPit
• Start of the cycle after Menses

  Menses = progesterone falls -> inhibition of Hypothalamus = GnRH no longer inhibited so -> AntPit = FSH production -> follicle development -> progesterone increase
• Major players of the cycle:


  GnRH- hypothalamus -> stimulates AntPit FSH- AntPit -> stimulates growth + maturation of follicles Oestrogen- Follicles ->tells Hypo to stimulate AntPit - release Luteinising Hormone - AntPit-> triggers ovulation Progesterone - Corpus Luteum -> Alters lining of uterus (endometrium) + inhibits further GnRH release in Hypo
• The 4 stages of the cycle

  1st- Menses 2nd- Follicular phase 3rd- Ovulation 4th- Luteal Phase
• Follicular phase:


  (postmenstrual) Hormones= OES< FSH< LH Process -> preparing follicles for ovulation FSH -> AntPit stimulates growth of many follicles -> each produce OES -> prepares endometrium -> follicle becomes dominant + others die
• Pre-ovulation

  The graafian follicle sends urge of OES through bloodstream = LH release -> prompting ovulation
• Ovulation:


  (The follicle doesn't enter the fallopian tube) Ovum erupts from follicle including corona radiata Fimbriae sweep ovum/muscle contraction in tube guide ovum
• Luteal Phase:


  Cells of ruptured primary follicle enlarge + form Corpus Luteum (what's left of follicle) Progesterone increases, grows for 7-8days if no fertilization -> growth stops and progesterone + FSH stop being produced
• Outcome 1: Fertilization


  Egg lives= 12-24hrs Must occur in uterine tube Endometrium development continues Progesterone is produced
• Progesterone


  Production continues -> maintained by several pathways: Formation of placenta from cells of trophoblast after implantation
• Outcome 2: No fertilization


  No Blastocyst means no HCG to ovary Corpus Luteum stops action -> degenerates Drop in Progesterone causes constriction of endometrial arterioles -> leads to endometrial ischaemia Causes spongy tissue of endo to slough off (menstrual bleed)