Lecture 06: Female Reproductive Cycle (Kelleman) Flashcards Preview

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Flashcards in Lecture 06: Female Reproductive Cycle (Kelleman) Deck (45):
1

estrous cycle

reproductive cycle of non-primate species. Period from one estrus to the next.

2

2 phases of estrous cycle

follicular and luteal

3

estrous vs. estrus

estrous refers to the cycle, estrus refers to period of behavioral receptivity during the estrous cycle

4

Monoestrous and species

one estrous cycle per year. Wolves, foxes, bears, most dogs

5

polyestrous and species

repeated estrous cycles are uniformly distributed throughout the year. Cattle, swine, rodents

6

seasonally polyestrous and species

repeated estrous cycles for a PORTION of the year. Horses, sheep, goats, cats

7

anestrus

any time period when the female is not cycling

8

cyclicity of seasonal breeders is determined by which environmental factors? What hormone do these factors directly influence?

photoperiod and temperature. Regulates melatonin secretion

9

More melatonin is produced in darkness or light?

darkness!

10

what produces melatonin?

pineal gland. It is an indoleamin hormone

11

Short-day breeders and species

cyclicity occurs during fall months, give birth in spring. Sheep, goats

12

melatonin stimulates or inhibits GnRH secretion in short day breeders? ****

stimulates

13

Long-day breeders and species

cycle in spring/summer and give birth in spring. Horses

14

melatonin stimulates or inhibits GnRH secretion in long day breeders? ***

inhibits

15

What does melatonin act on?

hypothalamus

16

What hormone does hypothalamus release (in reference to cyclicity)?

GnRH

17

What does GnRH act on?

pituitary gland

18

What hormones are released by pituitary gland (in reference to cyclicity)

FSH, LH

19

What do FSH and LH act on?

gonads

20

What is reproductive cyclicity driven by?

secretion of hypothalamic and pituitary hormones

21

How is progesterone used clinically?

used to make fake CL and keep animal out of heat

22

Prostaglandin fx

luteolysis (killing off CL)

23

FSH, LH, and inhibin are included in which class of hormones?

glycoproteins

24

GnRH function

(released by hypothalamus) stimulates synthesis and secretion of LH and FSH from anterior pituitary gland

25

FSH fx

(released from AP) promotes follicular development in the female.

26

LH fx

(released from AP) causes final follicular maturation and ovulation. Promotes development and maintenance of CL

27

What hormones inhibit FSH?

Inhibin, estrogen

28

What hormone inhibits LH?

Progesterone

29

Where is estrogen produced? Fx?

Produced in ovarian follicles.
-Causes estrous behavior, ONLY when progesterone is low.
-Inhibits FSH
-High lvls cause GnRH and LH surge

30

Where is progesterone produced? Fx?

Corpus luteum
-Pregnancy maintenance
-Inhibits estrous behavior
-Inhibits GnRH, LH

31

Where is prostaglandin produced? Fx?

Endometrium
-Causes destruction of CL

32

Decreasing Prostaglandin --> GnRH

increases

33

Which estrous phase has high progesterone?

luteal phase

34

Which estrous phase has high estrogen?

follicular phase

35

In which phase of estrous cycle does ovulation occur?

follicular phase

36

2 subdivisions of follicular phase

Proestrus and estrus

37

2 subdivisions of luteal phase

metestrus and diestrus

38

Main events of proestrus

1) declining progesterone, rising estrogen
2) 3rd wave of follicles recruited, dominant follicle selected but doesn't ovulate yet
3) female attracts male but doesn't allow mating

39

Main events of estrus

1) high estrogen, low progesterone
2) ovulation of dominant follicle occurs
3) female receptive and mating occurs

40

Main events of metestrus

1) declining estrogen, rising progesterone
2) CL forming
3) female not receptive
4) 1st wave of new follicles recruited, but does not reach ovulation because of high progesterone

41

Main events of diestrus

1) High progesterone, low estrogen
2) 2nd wave of follicles recruited, ovulation not reached because of high progesterone
3) female refuses male

42

luteolysis and when it occurs

when no pregnancy, prostaglandin released by endometrium and CL destroyed. Occurs at end of diestrus

43

Order of estrous cycle phases

Proestrus --> estrus --> metestrus --> diestrus "PEMD"

44

How do rising lvls of estrogen feed back to surge center of hypothalamus? ***

Positive feedback loop. Estrogen --> GnRH --> LH --> ovulation and spinofollicular maturation

45

How does inhibin released by dominant follicle feed back to hypothalamus?

negative feedback loop. Inhibits FSH

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