Histology of Follicular Development

Question 1

2 main supporting mesenteries of the ovary

Answer 1

Mesovarium
Mesosalpinx (of broad ligament)

Question 2

What structure is responsible for:

• production of female gametes
• secretion of estrogen and progesterones
• regulation of postnatal growth of repro organs
• dev’t of secondary sex characteristics

Answer 2

Ovary

Question 3

Each ovary is lined by an ovarian surface epithelium = ____ _____ epithelium with a peripheral dense CT called the ____ ______

Answer 3

Simple squamous-to-low cuboidal; tunica albuginea

Question 4

Each ovary has a peripheral cortex with a deep medulla.

In which layer would you find CT, interstitial cells, neurovasculature, and lymphatics?

Answer 4

Medulla

Question 5

Each ovary has a peripheral cortex with a deep medulla.

In which layer would you find CT and follicles with primary oocytes? At what stage of meiosis are these oocytes?

Answer 5

Cortex; follicles with primary oocytes that are arrested at prophase I

Question 6

The ovarian surface epithelium (OSE) will form ______ cells and ______ cells which comprise the growing follicles after birth

Answer 6

Granulosa; stromal

Question 7

3 phases of the ovarian cycle

Answer 7

1. Follicular
2. Ovulatory
3. Luteal

Question 8

The follicular phase of the ovarian cycle involves the sequential dev’t of several primordial follicles. What are the 5 stages of the follicle as it develops?

Answer 8

1. Primary (unilayered) follicle
2. Secondary (multilayered) follicle
3. Pre-antral follicle
4. Antral follicle
5. Preovulatory follicle (graafian follicle)

Question 9

The relative proportions of the follicles are not maintained; mature follicles are much _____ relative to early follicles

Answer 9

Larger

Question 10

A follicle consists of a large, groing oocyte w/a large nucleus and prominent nucleolus. _______ cells surround the oocyte and support its rapid growth

Answer 10

Follicular

Question 11

Cells that have begin 1st meiotic division, arrested at prophase 1

Answer 11

Primary oocyte

Question 12

Single layer of cells that surround a primordial follicle, associated with a basement membrane

Answer 12

Follicular cells

Question 13

Follicular cells that proliferate and become stratified

Answer 13

Granulosa cells

Question 14

Granulosa cells will eventually segregate into what 3 cell groups?

Answer 14

Cumulus oophorus

Mural granulosa cells

Corona radiata

Question 15

Coat of glycoproteins that encases primary oocyte, involved with sperm recognition

Answer 15

Zona pellucida

Question 16

Ovarian stromal cells differentiate and form an outer covering surrounding the follicle, consisting of 2 layers. The _____ _____ is steroid-producing, while the _____ _____ consists of fibroblasts and smooth muscle

Answer 16

Theca interna; theca externa

Question 17

Cells that complete the 1st meiotic division (with LH stimulation), enter meiosis II but arrest at metaphase II

Answer 17

Secondary oocytes

Question 18

______ follicles are numerous throughout the cortex, are about 25 micrometers in diameter and surrouded by a simple squamous layer of granulosa cells

Answer 18

Primordial

Question 19

_____ cells are recruited to the primordial follicles to initiate folliculogenesis

Answer 19

Granulosa

Question 20

Primordial follicles that progress to primary follicles do so when the single layer of squamous granulosa cells becomes a _____ _____ layer of granulosa cells

Answer 20

Simple cuboidal

Question 21

What separates the granulosa cells from the stroma of the ovary?

Answer 21

Basal lamina

Question 22

When the ____ ____ begins to assemble, it separates the primary oocyte fom the granulosa cells

Answer 22

Zona pellucida

Question 23

When primary follicles begin to develop into secondary follicles, the granulosa cells proliferate into a ____ ____ epithelium and the ____ begins to organize

Answer 23

Stratified cuboidal; theca

Question 24

The ______ is a vascularized cell layer adjacent to the basal lamina supporting the granulosa cells

The _____ is a fibrous cellular layer continuous with the ovarian stroma

Answer 24

Theca interna

Theca externa

Question 25

With _____ follicles, small intercellular spaces called ______ develop among the granulosa cells These spaces contain _______ derived from blood vessels of the theca interna, which reaches the antrum by an osmotic gradient

Answer 25

Preantral; call-exner bodies Follicular fluid

Question 26

Secondary follicle —> preantral follicle can by a close transition, typically determined by the presence of what histological finding?

Answer 26

Call-Exner bodies

Question 27

In the antral follicle, call-exner bodies formed in the preantral follicle will coalesce into the ________

Answer 27

Antrum

Question 28

What is the function of granulosa cells surrounding the antral follicle?

Answer 28

Actively synthesize and secrete estrogen Produce follicular fluid

Question 29

The ______ follicle is when the antrum has reached its maximum size, and fluid segregates the granulosa cells

Answer 29

Preovulatory

Question 30

In the preovulatory follicle, fluid segregates the granulosa cells into: _______ _____ = anchors the primary oocyte to follicle, nutrient delivery channel __________ = line wall of follicle ________ = granulosa cells anchored to ZP

Answer 30

Cumulus oophorous Mural granulosa cells Corona radiata

Question 31

Describe the theca interna vs. theca externa in the preovulatory follicle

Answer 31

Theca interna = well-vascularized, elongated cells w/lipid droplets Theca externa = formed a CT, capsule-like layer, continuous with the ovarian stroma

Question 32

During the ovulatory phase, the mature preovulatory follicle protrudes from the ovarian surface, forming a _________. Proteolytic activity of the theca externa and _______ causes rupture

Answer 32

Stigma; tunica albuginea

Question 33

What happens to the gamete released during the ovulatory phase in terms of cellular development?

Answer 33

Completes meiosis I and becomes secondary oocyte (due to LH surge), but still needs to finish meiosis II It then enters the oviduct

Question 34

What cells/cell components repair the ovarian surface epithelium following follicle rupture?

Answer 34

Mural granulosa cells and theca interna

Question 35

After ovulation during the luteal phase, the residual mural granulosa cell layer folds and becomes part of the ________

Answer 35

Corpus luteum

Question 36

During the luteal phase in a process called luteinization the following events occur: 1. Breakdown of the follicle ______ 2. Blood vessel invasion of empty antrum, blood flows into the antral space and coagulates, forming a __________ 3. Mural granulosa cells become _________ cells 4. Theca interna cells become ________ cells

Answer 36

Basal lamina Corpus hemorrhagicum Granulosa lutein Theca lutein

Question 37

Function of the corpus luteum is regulated by what 2 gonadotropins?

Answer 37

LH | FSH

Question 38

FSH stimulates the production of ____ and _______ from the granulosa lutein cells LH stimulates the production of _____ and _____ by theca lutein cells. The latter is translocated into the granulosa lutein cells for aromatization into _____

Answer 38

Progesterone; estradiol Progesterone; androstenedione; estradiol

Question 39

During pregnancy, ____ and _____ upregulate the effects of estradiol produced by granulosa lutein cells by enhancing the production of estrogen receptors Estradiol stimulates granulosa lutein cells to take up _____ from blood, which is then stored in lipid droplets and transported to mitochondria for further progesterone synthesis

Answer 39

Prolactin; placental lactogens Cholesterol

Question 40

If fertilization does not occur, the corpus luteum undergoes a process of regression called _______, involving a programmed cell death (apoptosis). It is triggered by endometrial __________ It involves reduction in blood flow, T cell production of IFN-y, and macrophage production of TNF ligand

Answer 40

Luteolysis; prostaglandin F2a

Question 41

The corpus luteum promotes endometrial changes that support implantation. _________ cells have a hypertrophic, steroid-secreting appearance. They secrete progesterone and estrogen with FSH and LH stimulation, and will themselves express LH receptors as an essential step for luteinization ______ cells produce androstenedione and progesterone with LH stimulation

Answer 41

Granulosa lutein Theca lutein

Question 42

What happens to the corpus luteum during the luteal phase if fertilization DOES occur?

Answer 42

Corpus luteum continues to enlarge and produce progesterone and estrogen, under the stimulatory action of hCG from the trophoblast layer

Question 43

What happens to the corpus luteum during the luteal phase if fertilization DOES NOT occur?

Answer 43

Corpus luteum begins involution stage ~14 days after ovulation Luteolysis, regression of CL, leads to formation of corpus albicans Stromal CT replaces degenerating luteal cells

Question 44

_____ _____ is made up of a scar of CT that forms at the site of the corpus luteum after involution It is mostly collagen (type I) with a few fibroblasts of other cells and eventually becomes very small

Answer 44

Corpus ablicans

Question 45

T/F: involution of the corpus luteum typically involves atresia

Answer 45

FALSE - involution of the corpus luteum does not involve atresia, it is mediated by macrophages

Question 46

About 7 million primary oocytes exist in the ______ ovary Approximately 400,000 oocytes remain at ______ Only 400 follicles will ovulate monthly beginning at ______ The remaining follicles degenerate and form ______ follicles

Answer 46

Fetal Birth Puberty Atretic

Question 47

______ = failure of a follicle to ovulate; occurs in the fetal ovary, after birth, and at any stage of development

Answer 47

Atresia

Question 48

What is the purpose of follicular atresia?

Answer 48

Ensures that only viable follicles, containing oocytes of optimal quality for fertilization, are available

Question 49

______ is the primary mechanism for follicular atresia, ensuring regression of the follicle without causing an inflammatory response

Answer 49

Apoptosis

Question 50

During apoptosis process of follicular atresia, a ______ membrane is formed which is thick, folded, basement membrane material A folded _____ _____ and apoptotic fragmented oocyte can also be seen

Answer 50

Glassy Zona pellucida

Question 51

In the absence of fertilization, the CL undergoes involution and regression (proteolysis). Luteal cells are phagocytized by _____ and the former corpus luteum becomes the corpus albicans

Answer 51

Macrophages

Question 52

During the luteal phase, the antral cavity fills with blood/cell debris, becoming the _________ which is removed by ________

Answer 52

Corpus hemorrhagicum; macrophages

Question 53

When the antral cavity fills with blood/cell debris, the _______ cells collapse into antral cavity, which is filled with cholesterol esters, theca, blood vessels, WBCs

Answer 53

Granulosa lutein

Question 54

Granulosa lutein cells are often _____in color d/t carotenoid pigment, lutein

Answer 54

Yellow

Question 55

The corpus luteum becomes the corpus albicans if fertilization does not occur; if fertilization does occur, _______ will rescue the corpus luteum so that it remains viable for duration of pregnancy, which is similar in structure to LH

Answer 55

hCG

Question 56

During pregnancy, the corpus luteum produces increasing progesterone — what is its primary function?

Answer 56

Transforms uterine lining into adhesive and supportive structure important for implantation and early pregnancy

Question 57

There is a transient decrease in _____ following LH surge, which rebounds and peaks midluteal phase. Progesterone and estrogen reduce LH to basal levels; ______ compensates for this decline

Answer 57

Estrogen hCG

Question 58

Lutein cells secrete _____ which suppresses FSH in pregnancy, this is so that additional follicles are not produced in pregnancy

Answer 58

Inhibin A

Question 59

_______ = demise of an ovarian follicle; predominant process in the ovary that can occur at any time during development

Answer 59

Follicular atresia

Question 60

During atresia, the ______ and ______ undergo apoptosis, however ______ cells persist and repopulate the cellular stroma of the ovary

Answer 60

Granulosa cells; oocytes; thecal

Question 61

Thecal cells retain LH receptors and the ability to produce ______; collectively they are referred to as the _______ gland of the ovary

Answer 61

Androgens; interstitial