Lecture 6: Female Reproduction Flashcards
What makes up the female reproductive system?
- Ovary=> follicular development+oocyte (egg) production
- Uterine (fallopian) tube=> transportation of oocytes (eggs) from the ovary to the uterus
- Uterus=> site of an oocyte (egg) implantation
- Cervix
- Vagina
- Mammary gland=> milk production (only when nursing)
How does the oocyte travel throught the reproductive system?
Ovary-> abdominal cavity-> uterine (fallopian) tube= fimbria, ampulla, isthmus-> uterus
Is a mammary gland a reproductive organ?
No, it is a supporting organ-> modifed sweat gland
What is the ovary covered by?
Germinal epithelium (peritoneum) which is simple cuboidal
Different than normal peritoneum= simple squamous
What is the organization of the ovary?
- Epithelium= simple cuboidal (geminal epithelium)
- Tunica albuginea= dense CT
- Cortex (stroma)= outer CT layer containing ovarian follicles and stromal cells
- Medulla= innermost layer with mostly vacular tissue (BVs)
While the germinal epithelium covers the ovary, what covers the testes?
Tunica vaginalis: part of the peritoneum then deep to that is the tunica albuginea
Where are the oocytes and germinal cells in testes come from?
Migrate in from yolk sac
How many follicles each month start the process of development?
30 but then one become hormone independent and ovulates
How does it the development of the ovary differ from the development of the testis ?
- Ovary: absence of TDF, testosterone, mullerian inhibiting factor, ant i-mullerian hormone
- Testis: Presence of both TDF, testosterone (from leydig cells which is only in males) and mullerian inhibiting factor, anti-mullerian homrone ( from sertoli cells which is only in males)
What is the same in the female and males?
tunica albuginea
What is the ovarian follicle
sac of fluid with developing oocyte that is surrounded by CT in the cortex
What is the function of the follicles?
What is it marked by?
- Function: Maturation and release of an oocyte (egg)
- Marked by follicular phase of menstrual cycle
What oocyte gets released into the abdominal cavity?
Mature (2°) oocytes
The ovarian follicle goes through a series of developmental stages leading to ovulation. During this development the oocyte is _
arrested
What is the organization of follicles?
- Outer layer= stromal (CT) cells-> turn into theca cells
- Inner layer= follicular cells-> turn into grandulosa cells
- 1° oocyte= immature gamete
How does the menstrual cycle correlate with follicles?
- During follicular phase-> follicles secrete estrogen
- During luteal phase-> remnant follicles secrete progesterone
What are the different stages of the follicle?
- Primordial follicle
- 1° follicle
- 2° follicle
- Mature (graafian) follicle
Primordial follicle characteristics?
- Follicular cells (not granulsoum cells) = simple squamous cells surrounding the oocyte
- 1° oocyte arrested in prophase I [of meiosis]
List 1° follicle characteristics (4)
- Stromal cells (cortex) form theca external (CT) and theca internal (secrete androstenedione)
- Follicular cells -> Now granulosa cells are simply cuboidal and secrete estrogen
- Zona Pellucida= amorphous substance secreted by 1° oocyte (in b/w granulosa cells and the oocyte)
- 1° is slightly bigger
The theca interna cells produce androstenedione which is secreted to the granulosa cell (follicular cells) where it is converted to estradiol (estrogen)
In the 1° follicle, how are the granulosa cells and oocyte still connected
Zona pellucida is penetrated by cellular processes from the granulosa cells and oocytes that form gap junctions
List 2° follicle characteristics (7)
- theca externa+interna
- Granulosa cells= stratified cuboidal cells-> secrete liquor folliculi (secretes progesterone, estradiol. inhibin, etc)
- Antrum= formed from the droplets of liquor folliculi
- Cumulus oorphus= “bridge” of granulosa cells
- Corona Radiata= granulosa cells surrounding the zona pedullcida
- Zona pellucida= directly surrounding the 1° oocyte
- 1* oocyte slightly bigger
- Stromal cells develop into _
- Follicular cells develop into _
- theca externa and theca interna cells
- granulosa cells
Theca externa cells are what?
Theca internal cells do what?
- Theca externa cells are connective tissue in nature
- Theca interna cells produce androstenedione which is secreted to the granulosa cells where it is converted to estradiol (estrogen)
List the cells and epithelium type present in the stages listed below:
- Primordial follicle=
- 1°=
- 2°=
- mature=
- Primordial follicle=follicular cells + simple squamous
- 1° =granulosa cells + simple cuboidal
- 2 °= granulosa cells+ stratified cuboidal
- Mature= granulosa cells+ stratified cuboidal-> proliferation increase follicle size
_ is amorphous substance secreted between the granulosa cells and the oocyte.
Zona Pellucida
- During development the granulosa cells secrete _ _ into intercellular spaces.
- When these spaces become evident the follicle is classified as a _ _.
- This fluid contains several secretory products (_, _, _ etc.)
- Over time the spaces coalesce into a larger space called the _.
- During development the granulosa cells secrete liquor folliculi into intercellular spaces.
- When these spaces become evident the follicle is classified as a secondary follicle.
- This fluid contains several secretory products (progesterone, estradiol, inhibin etc.)
- Over time the spaces coalesce into a larger space called the antrum.
The granulosa cells in the secondary follicles that surround the oocyte are called what? What are they attached by?
corona radiata and attached to the other side by the cumulus oophorus
List Mature follicle characteristics (7)
- theca externa+interna
- Granulosa cells= stratified cuboidal-> proliferation increases follicle size
- Antrum= contains free-floating 1° oocyte (bc no bridge)
- Cumulus oorphus-> breaks down just before ovulation
- Corona radiata
- Zona Pellucida
- 1° oocyte remains the same size-> detaches from follicle wall
What does the mature follicle contain? What will it undergo?
- Contain a well defined ampulla
- Will undergo oogenesis before ovulation
What breaks down to allow the oocyte to float free in antrum
cumulus oophorus
What happens during ovulation?
The (mature) follicle swells through the tunica albuginea and germinal epithelium and bursts to release the egg into the pelvic cavity
then picked up by Fimbrae
When does oogensis occur?
just before ovulation
Explain the maturation process of oogenesis.
1° oocyte-> 2° oocyte
- Step 1= 1° oocyte (arrested in prophase I) undergoes 1st meiotic division
- Step 2= 1° oocyte finishes meiosis I à results in 2° oocyte + polar body
- Step 3 = 2° oocyte is arrested in metaphase II
- Step 4 = 2° oocyte gets released from its follicle upon ovulation
- the first meiotic divison is competed just prior to _
- the second meiotic division occurs only if _ occurs
- Ovulation
- Fertilization-> this typically occurs in the fallopian tube
Oogenesis is regulated by what?
Hormones:
- Oocyte maturation inhibitor (OMI) from follicular cells -> arrests in 1° oocyte in prophase I
- Maturation promoting factor (MPF)-> completion of 1st meiotic division to produce 2° oocytes
What is the process of releasing a 2° oocyte from a mature ovarian follicle?
- The 2° oocyte is released into the abdominal cavity-> finds its way to the oviduct (uterine tube) through fimbriae
- The process occurs each month after the onset of puberty
What initiates ovulation ?
an increase in estrogen from the granulosa cells as the follicle develops which causing an LH surge
What happens to the follicle during ovulation?
follicle swells through the ovary
- Moves from the cortex through the tunica aluginea and eplithelium of the ovary
- Then, the follicle bursts open-> releases 2° oocyte into abdominal cavity
Explain what occurs before ovulation:
- Phase?
- What is happening?
- Characterized by?
- Before ovulation = follicular phase of the menstrual cycle:
- Stromal cells-> now Theca interna cells secrete androstenedione
- Follicular cells-> now Granulosa cells convert androstenedione to estrogen
- Characterized by the development of ovarian follicles + oocytes
What is increase during the follicular phase?
estrogen because granulosa cells convert androsterndione to estrogen
What is the name of the stage after ovulation?
luteal phase
What are the cells during in the luteal phase of the menstrual cycle?
- Stromal cells->Theca interna cells-> now Theca lutean cells secrete androstenedione + progesterone
- Follicular cells -> Granulosa cells -> now Granulosa lutean cells produce estrogen + progesterone
Post-ovulation is characterized by what?
Characterized by the degradation of ovarian follicles after the release of 2° oocyte
What is the Corpora (Corpus) Lutean
The remnant follicle that remains after releasing its 2° oocyte
- Consists of the Theca lutean + Granulosa lutean cells
During pregnancy, the corpora lutean is maintained for how long?
3 months
If the egg is not fertilized, then the corpora (corpus) lutean turns into what?
the corpora albucans and involutes
corpus luteum
What is the oviduct?
uterine (fallopain) tube