Lesson 2

• female anatomy


  Ureter

  Fallopian tube/oviduct

  Fimbriae

  Uterus

  Urinary bladder

  Cervix

  Urethra

  Clitoris

  Labia minora

  Labia majora

  Vagina
• Ovaries function


  Paired gonads, produce eggs (gametes), estorogen + progesterone

  -follicles contain oocyte plus surrounding follicle cells

  -female born with ~ 2 million follicles, reduced to ~350 000 - 400 000 at puberty

  - ~ 400 eggs mature; ~ 1 egg released per month on average

  Study diagram
• Oviducts (fallopian tubes) function

  Tubes from ovaries to uterus

  -cilia lining, fimbriae (fingerlike projections draped over ovaries)

  -egg bursts from ovary, swept into oviuct via combined action of fimbriae, tubular muscle contractions, cilia movement

  -sperm usually meet + fertilize egg in upper oviduct
• Uterus function


  Muscular sac that nurtures embryo then developing fetus

  Can stretch 5-30cm wide with growing fetus
• Endometrium


  Lining of uterus - made of connective tissue, glands, + blood vessels

  -composed of a basal layer + inner functional layer (varies in thickness during female hormone cycle)

  -forms placenta if pregnancy occurs
• Cervix function


  Opening to uterus at back of vaginal canal

  -only open 3-5 days prior to ovulation, closed rest of time
• Vagina function


  Muscular tube with mucosal lining

  -receives penis during intercourse

  -birth canal during childbirth
• Labia Majora/Minora


  Outer/inner pair of fat-padded skin folds that extend from the vaginal opening to the clitoris

  -protects the reproductive organs
• Clitoris


  Shaft of erectile tissue capped by the glans

  -houses sensory receptors

  -stimulation leads to orgasm
• Female hormones - estrogen (estradiol/estriol)


  stimulates the growth of the primary sex organs (uterus, ovaries, vagina)

  -oversees egg maturation at puberty

  -causes/maintains secondary sex characteristics at puberty: -breasts - > development prepares them to produce milk via 1-2 dozen lobules with many mammary ducts ending in alveoli

  -body - underarm, pubic hair, wider pelvic development, fat deposits under skin
• Female hormones - progesterone


  Supports embryo development leading to gestation (fetus development) during pregnancy
• Ovarian cycle


  Describes the female hormone fluctuation and egg development
• Ovarian cycle - Menstruation (Day 1 - 5)


  Part of endometrium + small amount of blood released through vagina

  - decreased levels of female hormones estrogen, progesterone, FSH, LH, GnRH cause menstruation

  - endometrium at its thinnest

  - decreased levels of female hormones detected by hypothalamus, causing it to release GnRH

  - GnRH sent to anterior pituitary gland causing release of FSH + LH
• Ovarian cycle - Follicular phase (Day 6 - 13)


  Endometrial thickening

  - ant. Pituitary gland releases increased FSH - follicles mature - they increase in size - produce increased estrogen

  - increased levels of estrogen thicken endometrium via proliferation of blood vessels + mucus glands

  A) negative feedback: egg finished maturing = end of follicular phase; increase follicular estrogen levels = ant. Pituitary realeses decrease FSH

  B) positive feedback: increased follicular estrogen levels = increased GnRH to be released by hypothalamus = ant. Pituitary released more LH
• Ovarian cycle - ovulation (day 14)


  Egg release

  -"LH surge" -> mature follicles rupture, releasing egg

  - remaining follicle cells make up corpus luteum
• Ovarian cycle - Luteal Phase (day 15-28)


  Continued thickening

  - corpus luteum produces increased amounts of progesterone + moderate amounts of estrogen, endometrium thickens 2X

  - as endometrium thickens, mucus glands mature and begins secreting thick mucus material
• Ovarian cycle negative feedback


  - remaining estrogen inhibits hypothalamus from secreting GnRH which inhibiting ant. Pit. From secreting for FSH and LH

  - increased luteal progesterone levels cause ant. Pit. To release less LH by day 24/25 which in turn cause corpus luteum to degenerate

  - as corpus luteum degenerates it makes less progesterone + estrogen

  - without more progesterone and moderate estrogen, endometrium cannot maintain thickness + starts to disintegrate by day 28

  
  

  Study diagram
• Uterine cycle


  Describes fluctuation in thickness of endometrium

  1) Menstruation (day 1-5): breakdown of endometrium due to low hormone levels

  2) proliferative phase (day 6-13): endometrium gets thicker due to increased estrogen levels

  3) secretory phase (day 15-28) endometrium continues to thicken + mature mucus (uterine) glands secrete mucus due to more progesterone levels
• Fertilization


  Joining of egg and sperm resulting in a zygote
• Implantation


  -fertilization

  -cell division (mitosis) leads to development of embryo

  -embryo embeds into endometrium within days of fertilization

  -further cell division/specialization leads to fetus

  -usual ovarian/uterine cycle interrupted for 9 months as fetus grows in uterus

  -as placenta develops it makes its own progesterone and estrogen (via HCG) which maintains the endometrium = menstruation cancelled

  -release of FSH + LH from ant. Pit shut down - no new follicles mature, corpus luteum eventually disintegrates
• Childbirth hormones - oxytocin


  Oxytocin: peptide hormone produced in hypothalamus, stored

  in posterior pituitary gland

  Positive feedback - Childbirth:

  ● fetal head exerts pressure against cervix stimulating sensory

  nerves → signal hypothalamus to produce oxytocin → signals

  posterior pituitary to release oxytocin

  ● oxytocin stimulates uterine muscle contractions, contractions

  stimulate release of more oxytocin

  Positive feedback - Breastfeeding:

  ● nipple sucking by infant stimulates sensory nerves →

  signal hypothalamus to produce oxytocin → signals posterior

  pituitary to release oxytocin

  ● oxytocin stimulates release of milk from mammary glands, milk release stimulates release of more oxytocin
• Functions of oxytocin still being studied - Mother:


  ● female sexual arousal + "falling in love"

  ● maternal behavior, increasing trust & reducing fear,

  increasing empathy
• Functions of oxytocin still being studied - Fetus:


  ● inhibiting addictive drug tolerance development &

  reducing drug withdrawal symptoms

  ● preparing fetal neurons for lack of oxygen during delivery

  (reducing vulnerability to hypoxic damage)
• Prolactin


  Peptides hormone hormone produced by anterior pituitary gland

  -stimulates breast alveoli to produce milk, more progesterone levels suppress milk production during pregnancy