Female Estrous Cycle/ Intro to Follicle Development

Question 1

Primordial follicles have what cell type?

Answer 1

squamous

Question 2

Primary cell types have what cell types?

Answer 2

cubodial

Question 3

What is the ESTROUS CYCLE?

Answer 3

series of predictable reproductive events that begin at estrus and continues until the subsequent events

Question 4

What is estrus? heat.

Answer 4

noun. period when female is receptive to copulation with the male

Question 5

what is Estrous?

Answer 5

adj. the length of the estrous cycle in the pig is 21 days

Question 6

What is anestrus?

Answer 6

without cyclicity: ovaries are relatively inactive, neither ovulatory follicles or corpora lutea are present (pregnant/ right after birth/ before puberty)

Question 7

What are the types of estrous cycles?

Answer 7

-Polyestrus: uniform distribution of estrous cycles throughout the year
-seasonally polyestrus: (sheep/horses)
clusters of estrous cycles that occur during certain seasons of the year
-monoestrus: only one cycle per year (dogs/wolves)

Question 8

What is the follicular phase?

Answer 8

follicle is the dominant structure on the ovary
-proestrus+estrus
-Large antral follicles
-estrogen is secreted by the follicles (main hormone)

Question 9

What is the Luteal phase?

Answer 9

C.L is the dominant structure on the ovary
-metestrus+diestrus
-progesterone secreted by the CL is the primary hormone

Question 10

What is folliculogenesis? Species number?

Answer 10

some primordial follicles begin to grow continuously throughout life
-swine (10-25)
-sheep (1-3)
-cattle, horses, humans=1

Question 11

What is the primary hormone produced by the follicle?

Answer 11

estrogen

Question 12

What is the primary hormone produces by the C.L?

Answer 12

progesterone

Question 13

What blocks the animal from going into heat?

Answer 13

progesterone

Question 14

Describe a basic overview of follicular waves

Answer 14

-cohort of follicles recruited initially
-some of these will continue to develop , while others undergo atresia
-a dominant follicle is selected for continued growth to preovulatory size
-if this follicle achieves dominance around the time of luteolysis, it will ovulate

Question 15

At the time of recruitment, what stage are the follicles in?

Answer 15

tertiary, just small

Question 16

What is the StAR protein?

Answer 16

Steroidogenic acute regulatory protein, transport protein that transfers cholesterol into the inner mitochondrial membrane
- this is the RATE LIMITING step for steroidogenesis

Question 17

What is happening to the levels of estrogen during the growth of the follicles?

Answer 17

with the highest quality follicle, more estrogen is produced

Question 18

When does ovulation occur?

Answer 18

when progesterone declines, end of luteolysis (regression of the C.L)

Question 19

What is happening in metestrus?

Answer 19

Luteal phase, right after ovulation form the previous cycle, corpus medi. here

Question 20

What is happening in the Diestrus phase?

Answer 20

The C.L is mature, Producing max amount of progesterone, majority of the cycle

Question 21

What is happening in proestrus?

Answer 21

progesterone declines, no signs of sexual reset

Question 22

What happens on the last follicular wave?

Answer 22

occurring after luteolysis, results in a dominant follicle that will ovulate. Only those follicles recruited during or after luteolysis will become eligible for ovulation. Follicles from any wave that are in the growth phase when luteolysos occurs are capable of ovulation.

Question 23

What happens to follicles during peak progesterone?

Answer 23

they become atretic

Question 24

What happens during recruitment (hormones/brain)

Answer 24

entry into gonadotropin sensitive pool, Anterior Lobe is producing alot of FSH, little LH on the ovary. The ovary is producing estrogen (negative feedback on the surge center)
-LH on theca cells, no FSH receptor on granulosa cells
-FSH plays a more important role than LH in antral follicle growth

Question 25

What happens during selection (brain/hormones)

Answer 25

some granulosa cells have gained LH receptors, FSH production has decreased, follicles producing estrogen and now inhibin (negative feedback on the surge center of the hypothalamus) -estrogen acts on the Anterior Lobe, to stop production of FSH

Question 26

What happens during dominance in a follicle (hormones)

Answer 26

The largest follicles produce more and more estrogen, this prompts a surge of LH. FSH secretion is low due to inhibin and estrogen are secreted in high levels by the dominant follicle -The drop in FSH is believed to cause other antral follicles to undergo atresia -Estrogen production is at the highest

Question 27

How is the antrum formed?

Answer 27

from the stimulation of FSH, small pockets form together

Question 28

List the layers of the ovary from outer to inner.

Answer 28

germinal epithelium, tunica albuginea, ovarian cortex, ovarian medulla

Question 29

Where is the site of fertilization?

Answer 29

ampullary-isthmuc junction

Question 30

what are theca externa cells

Answer 30

outermost layer of the tertiary follicle that helps support integrity and growth

Question 31

What are theca interna cells

Answer 31

layer of cells bordering the exterior portion of the basement membrane that are important for producing androgens like testosterone

Question 32

What is the basement membrane

Answer 32

provides structural support to the developing follicles, maintaining cellular organization

Question 33

What are granulosa cells

Answer 33

layer of cells bordering the interior portion of the basement membrane that are important for producing estrogen

Question 34

What are corona radiata?

Answer 34

specialized granulosa cells that are in direct contact with the oocyte

Question 35

what is the stroma layer?

Answer 35

connective tissue of the ovary

Question 36

How long is the cow's estrous cycle, duration of estrous, and timing of ovulation?

Answer 36

21 days, 15 hours, 24-32 hours

Question 37

How long is the mare's estrous cycle, duration of estrous, and timing of ovulation?

Answer 37

21 days, 7 days, 5 days

Question 38

How long is the sow's estrous cycle, duration of estrous, and timing of ovulation?

Answer 38

21 days, 50 hours, 36-44 hours

Question 39

How long is the ewe's estrous cycle, duration of estrous, and timing of ovulation?

Answer 39

17 days, 30 hours, 24-30 hours

Question 40

why would anestrus occur?

Answer 40

prepubertal, pregnant, anorexic/obese, shortly after parturition, sickness/illness

Question 41

What is the period immediately preceding estrus, give characteristics of this phase

Answer 41

proestrus -formation of ovulatory follicles/ e2 secretion main hormone -begins when progesterone declines -a part of the follicular phase

Question 42

What is estrus?

Answer 42

sexual receptivity and peak estrogen secretion -female allows for copulation -visual behavioral signs

Question 43

What is metestrus?

Answer 43

CL formation+ beginning of progesterone secretion -transition from estrogen to progesterone dominance -formation of corpora lutea

Question 44

What is diestrus?

Answer 44

-sustained luteal secretion of progesterone -period of maximum luteal function -longest stage of the estrous cycle and is a time when the corpus luteam is fully functional -progesterone secretion is at the the highest

Question 45

What are the normal stages of estrous?

Answer 45

estrus, metestrus, diestrus, proestrus, estrus

Question 46

What is anestrus?

Answer 46

-means without heat or estrus -result of insufficient GnRH release from the hypothalamus to stimulate and maintain gonadotropin secretion