Reproduction II Flashcards

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1
Q

what are the functions of the female reproductive system?

A
  • produce ova (eggs)
  • receive sperm, facilitate fertilization
  • house and nourish developing embryo, gives birth
  • lactate, feed young
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2
Q

describe the anatomy of the female reproductive system

A
  • ovaries: female gonad
  • endocrine gland
  • located in abdominal cavity
  • held in place by several ligaments
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3
Q

what does the female reproductive system produce?

A
  • gametes via oogenesis

- sex hormones - estradiol, progesterone

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4
Q

what are within the ovaries?

A
  • follicles - where egg will mature and be released

- oocytes - cell that undergoes meiosis to produce eggs

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5
Q

oviducts (fallopian tubes)

A
  • extend from uterus to each ovary, partially surround
  • site of fertilization
  • collects 2° oocyte from ovary, brings it to the uterus
  • move oocytes via beating cilia, contractions
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6
Q

uterus

A
  • pear-shaped, ~ size of fist
  • site of embryonic development (expands during pregnancy)
  • 2 layers:
    (1) myometrium: thick wall of smooth muscle
    (2) endometerium: lines lumen
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7
Q

endometrium

A
  • lines lumen - connective tissue, glands, blood vessels
  • thickens each month - prepare for pregnancy
  • fertilization -> embryo implants
  • no fertilization -> sloughed off -> menstruation
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8
Q

cervix

A
  • lower part of uterus
  • closes uterus, separates from vagina
  • common site of cancer
  • > 90% cases due to HIV
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9
Q

vagina

A
  • elastic muscular tube
  • extends to outside of body
  • receives penis and sperm
  • birth canal
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10
Q

name the parts to the vulva

A
  • external genitalia
  • labia majora
  • labia minora
  • clitoris - homologous with glans penis
  • prepuce (clitoral hood) - homologous with foreskin
  • urethra
  • vaginal opening
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11
Q

what is oogenesis?

A

development of mature eggs

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12
Q

SEQ oogenesis prior to puberty

A

primordial germ cells (2n) -> mitosis -> oogonia (2n) -> mitosis -> 1° oocyte (2n)

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13
Q

1° oocytes

A
  • begin meiosis, but stop in Prophase I
  • arrested in Prophase I
  • at birth, ~ 1-2 million 1° oocytes
  • ~ 200k by sexual maturity
  • each 1° oocyte within a follicle
  • all are dormant until puberty -> a few mature each month
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14
Q

oogenesis starting at puberty

A

-each moth, 6-12 follicles mature within ovaries -> 1° oocyte grows, follicle cells around it proliferate (but only one will mature)

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15
Q

follicle cells

A

protective barrier

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16
Q

zona pellucide

A

thick glycoprotein layer between follicle cells and oocyte

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17
Q

what happens just before ovulation (each month)?

A

8-10 hours before release from follicle, 1° oocyte completes meiosis I, producing a polar body (n) and a 2° oocyte (n), which starts meiosis II but arrests at metaphase II

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18
Q

what happens in ovulation?

A
  • as 2° oocyte matures, it moves to surface of ovary

- follicle cells secrete fluid, estrogens, enzymes -> break down ovary wall

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19
Q

ovulation

A

2° oocyte ejected from ovary in oviduct

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20
Q

Corpus Luteum

A
  • “yellow body”
  • portion of follicle left in ovary after ovulation
  • develops into temporary endocrine gland (more later)
  • secretes: estrogens and Progesterone (1000x more than estrogens)
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21
Q

what happens if sperm enters into the Corpus Luteum

A
  • 2° oocyte completes meiosis II -> becomes a mature egg containing sperm nucleus
  • oogenesis is complete!
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22
Q

what happens if no sperm enters into the Corpus Luteum?

A
  • 2° oocyte disintegrates
  • Corpus Luteum dies
  • endometrium shed - Menstruation
  • new follicle next cycle
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23
Q

menstrual cycle

A
  • all mammals - endometrium thickens before ovulation
  • only some have menstrual cycles
  • estrous cycle
  • menstrous cycle
24
Q

estrous cycle

A

fertile, sexually receptive (“in heat”) only at certain times of year - most mammals

25
Q

menstrous cycle

A

fertile intermittently, on a cyclic basis

26
Q

what are the components to the menstrual cycle

A
  • cyclic process of gamete maturation AND uterine lining development - prepares female body for pregnancy
  • repeats every ~ 28 days unless fertilization and implantation occur
27
Q

what are the two concurrent cycles to the menstrual cycle

A

ovarian cycle and uterine cycle

28
Q

ovarian cycle

A
  • follicular phase - follicle/oocyte maturation
  • ovulation ~ Day 14
  • Lutuel Phase - after ovulation, hormones from Corpus Luteum
29
Q

uterine cycle

A
  • menstrual flow phase - Days 1-5
  • Proliferative Phase - endometrium starts again, before ovulation
  • secretory phase - endometrium thickens, after ovulation
30
Q

estrogen

A

principle female sex hormone

31
Q

what is the main form of estrogen?

A

estradiol

  • secreted by follicle cells, then by corpus luteum
  • at puberty, stimulates growth of
    (1) 1° sex characteristics
    (2) 2° sex characteristics
  • stimulates monthly ovulation and endometrium thickening
32
Q

what is the difference between 1° and 2° sex characteristics?

A

1° - sex organs

2° - breast development, broadening of pelvis, fat and muscle distribution

33
Q

progesterone

A
  • secreted mainly by corpus luteum
  • completes preparation of endometrium for pregnancy, maintains it
  • stimulates endometrial glands to secrete nutrient-rich fluid
34
Q

SEQ the General Hormone Cascade

A

Hypothalamus -> GnRH -> AP -> FSH, LH -> Ovaries -> Estradiol and Progesterone

35
Q

what are the different female sex hormones?

A

estrogen, estradiol and progesterone

36
Q

what are the 3 different phases of the ovarian cycle, and how long does each last?

A
  • follicular phase (Days 1-13)
  • ovulation (Day 14)
  • luteal phase (Days 15-28)
37
Q

follicular phase

A
  • FSH and LH stimulate follicle growth in ovaries

- as follicle grows, it releases more and more estradiol

38
Q

what happens when follicle cells produce estradiol?

A
  • slow rise during follicular phase

- low estradiol levels inhibit FSH and LH secretion by AP

39
Q

SEQ Follicular phase - regulation (inhibition)

A

hypothalamus -> GnRH -> AP -> LH and FSH -> early follicle -> (inhibition) AP

40
Q

SEQ Follicular phase - regulation (stimulation)

A

hypothalamus -> GnRH -> AP -> LH and FSH -> early follicle -> follicle matures -> late follicle -> (stimulation) high estradiol -> hypothalamus

41
Q

what happens when there are low levels of estradiol?

A

negative feedback on AP

42
Q

what happens when there are high levels of estradiol?

A

positive feedback on hypothalamus

43
Q

maturing follicle

A
  • enlarges and move to ovary surface
  • ovulation ~ 1 day after LH surge
  • 2° oocyte released into oviduct
  • ovulation is due to positive feedback regulation
44
Q

ovulation - regulation

A
  • high levels of estradiol from mature follicle
  • Positive feedback on hypothalamus
  • high GnRH stimulates AP
  • LH surge -> ovulation
  • 2° oocyte to oviduct
45
Q

luteal phase

A

-LH stimulates remaining follicle tissues -> corpus luteum -> secretes progesterone and estradiol -> (inhibit) hypothalamus

46
Q

what is the effect of the inhibition that occurs in the luteal phase?

A

low GnRH and low LH and FSH

47
Q

what is the effect of estradiol and progesterone from corpus luteum?

A

negative feedback on hypothalamus

48
Q

what happens if there is no pregnancy in ovarian cycle?

A
  • low FSH and LH cause corpus luteum to disintegrate
  • low [estradiol] and [progesterone]
  • hypothalamus secretes GnRH -> AP produces FSH -> stimulates next ovarian cycle
49
Q

what happens if there is pregnancy in ovarian cycle?

A
  • placenta releases human chorionic gonadotropin (hCG), which maintains the corpus luteum
  • [estradiol] and [progesterone] remain high -> hypothalamus does NOT secrete GnRH -> AP does NOT produce FSH or LH -> no new ovarian cycle
50
Q

what are the three phases of uterine cycle, and how long does each last?

A
  • menstrual flow phase (Days 1-5)
  • proliferative phase (Days 6-13) - before ovulation
  • secretory phase (Days 15-28) - after ovulation
51
Q

proliferative phase

A
  • coordinated with follicular phase of ovarian cycle
  • ovarian hormones stimulate uterus to prepare, support embryo
  • growing follicle -> estradiol -> endometrium thickens
52
Q

secretory phase

A
  • coordinated with luteal phase of ovarian cycle

- corpus luteum secretes estradiol and progesterone -> endometrium development

53
Q

endometrium development

A
  • arteries enlarge
  • endometrial glands grow
  • secrete nutrient fluid -> sustain early embryo before implant
54
Q

what happens if there’s no pregnancy in the uterine cycle?

A
  • corpus luteum disintegrates
  • low [estradiol] and [progesterone] -> arteries in endometrial lining constrict
  • loss of circulation
  • lining disintegrates
55
Q

menstrual flow phase

A
  • endometrial tissue, fluid, blood is shed
  • new follicle begin to grow
  • Day 1 of menstrual flow -> beginning of new ovarian/uterine cycles