36 Flashcards
Name the layers of the uterine wall from outer most to inner most. Which layer is shed during mestruation ?
- perimetrium
- myometrium
- endometrium (shed)
Which artery associated with the female reproductive tract branches directly off the abdominal aorta? Which ligament does this artery run through?
- avarian artery
- runs through the suspensory ligament
Name the finger like projections on the infundibulum. What is their purpose?
- fimbriae
- help guide the oocyte to the opening of the unterine tube
Name the ligament labeled X:
Mesovirain
What is Oogenesis
• Formation and development of the oocyte (female gamete)
from oogonia.
Oogenesis requires ____ and _____
Mitosis
Meiosis
What are the stem cells of female sex cells called
Oogonia
When does oogenesis happen?
- initiated before birth
You are born with a lifetime supply of gametes - then halts
- continues between puberty and menopause
- cyclic - 1 ovulation every 28 days
- (only the dominant oocyte within the dominant follicle
goes onto ovulation)
Where do oocytes develop?
within ovarian follicles (1 oocyte per follicle).
Before Birth - what process happens in oogenesis
MITOSIS
• Oogonium (diploid, 2n=46) in gonad
• Population of oogonia increase by mitosis (stops before
birth)
• Oogonia differentiate to form primary oocytes
(diploid,2n=46)
- they are encased in primordial follicle
- many primary oocytes undergo atresia
• Primary oocytes start meiosis.
• Meiosis halts at prophase I
• Halts until puberty begins
Female born with all the primordial follicles - each of which contains an oocyte
From Menarche till Menopause - what process is happening in Oogenesis ?
MEIOSIS 1
• At puberty, females have ~300,000 oocytes (they had been undergoing atresia and reduced from 700,00)
• Under GnRH influence, small number of follicles recruited each ovarian/menstrual cycle. (This cohort grows to a point and then they’ll all start regressing except one - the dominant one)
• Only one oocyte will complete development and ovulate (within dominant follicle).
• Primary oocyte completes meiosis I. (ONLY THE DOMINANT
ONE)
• Forms a secondary oocyte and 1st polar body (both haploid, n=23).
From Menarche till Menopause - what process of oogenesis happens after meiosis 1
• Secondary oocyte starts meiosis II
• Halts at metaphase II
• Suspended until fertilisation.
• Meiosis II resumes when the sperm penetrates plasma membrane of the ovum at fertilisation
- if not fertilised, will degenerate (atresia) and therefore
never complete meiosis
Meiosis two only happens if…
Fertilisation takes place
Howdy
Oogenesis occurs within….
Oogenesis occurs within developing follicle
Oocyte develops within developing …
follicle
Is a follicle layered?
• Follicles are multilayered
• Granulosa cells
• Theca cells
What do granulosa cells produce?
estradiol
Ovulation
oocyte and corona radiata released into peritoneal cavity
• Oogenesis occurs in the ___________ and is the process of
oocyte formation from oogonia.
Ovary
The number of oogonia increases in the ovary by mitosis
before birth.
Yes
• Primary oocytes start meiosis prior to birth but the process
halts at ___________ until puberty begins.
Prophase 1
• After puberty, small groups of follicles start to grow each
ovarian cycle – only one of these follicles goes on to ovulate
(the ___________ follicle).
Dominant
• The dominant follicle begins meiosis II, but the process halts
at ___________ until fertilisation occurs.
Metaphase 2
• Oocyte growth and development occurs within ovarian
follicles.
Yes
Female Reproductive Hormones
Hypothalamus:
- GnRH (Gonadotrophin Releasing Hormone)
Anterior Pituitary:
- FSH (Follicle Stimulating Hormone)
- LH (Luteinizing Hormone)
Ovary (follicles): Estradiol (an estrogen), Inhibin
Ovary (corpus luteum): Inhibin, Progesterone
Function of GnRH
GnRH (hypothalamus): Release of FSH and LH.
Function of FSH
FSH (anterior pituitary): Stimulates the growth of ovarian follicles.
Function of LH
LH (anterior pituitary): Surge of LH involved in ovulation, formation of corpus luteum.
Fucngtion of Estradiol
Estradiol (developing follicles): Assists follicle growth (with FSH); bone and muscle growth; endometrial growth; secondary sex characteristics; feedback to anterior pituitary.
Function of inhibin
Inhibin (granulosa cells): Negative feedback to anterior pituitary to suppress FSH.
Function of Progesterone
Progesterone (corpus luteum): Negatively feeds back to suppress GnRH (therefore LH and FSH); endometrial maturation; maintains pregnant state.
- helps thicken civical mucus to prevent the movement of spermatazoa
What are the Ovarian/Menstrual Cycles
The regular cyclic changes in the ovary and uterus that prepare an oocyte/ova for fertilisation and the endometrium for embryo implantation.
• Menstrual cycles occur on an approximately _____ basis
(average 28 days) between _______ and ______.
• Menstrual cycles occur on an approximately monthly basis
(average 28 days) between menarche and menopause.
What is menarche
first menstrual period
When does menarche occur?
• Occurs at age 12-13 y on average
• Part of puberty – orchestrated by increase in sex steroid
production (estrogens) by the gonads
What is menopause ?
cessation of menstruation
When does menopause occur?
• Typically occurs in early 50s
What happens when menopause
• Reduction of estradiol and progesterone due to absence of
or lack of response by follicles
• Anterior pituitary feedback no longer active ∴ FSH/LH high
Why does menopause happen
No follicles
Female Reproductive Cycle - Ovarian - what are the two phases called and how long do they last?
• Follicular (preovulatory phase): Day 1 - 14
• Luteal (postovulatory phase): Day 15 - 28
Follicular (preovulatory) phase: Day 1 - 14.
• Increased FSH from the anterior pituitary
• Stimulates follicular growth
• Growing follicles secrete estradiol and inhibin
• Reduces FSH from anterior pituitary (negative feedback)
• Growing follicles undergo atresia (as they are dependent
on FSH for servival), except dominant follicle.
• Dominant follicle secretes large amounts of estradiol
• High estradiol stimulates surge of LH (positive feedback) -
(the surge in LH is what causes ovulation to take place)
• Follicle ruptures and ovulation occurs
• Oocyte enters peritoneal space/collected into uterine
tube.
Luteal (postovulatory phase): day 15 - 28
• Ovulated follicle collapses & forms corpus luteum
• Secretes progesterone, estradiol & inhibin.
• These decrease FSH & LH secretion.
• Negative feedback on hypothalamus.
• If fertilisation and implantation do not occur, the corpus luteum involutes (luteolysis).
• Fall in progesterone & estradiol.
• Removes negative feedback on FSH and LH…. Cycle starts
again…
Learn this yay
Menstrual (Endometrial) Cycle
- two phases and when they happen
- Menstrual and Proliferative: Day 1 - 14.
- Secretory (and premenstrual phase): Day 15 - 28.
Menstrual and Proliferative Phase
• Days 1 – 14
• Endometrium breaks down and bleeds during
menstruation (in response to the reduction on
progesterone)
• Estradiol stimulates endometrial growth from approx days
6-14
• Rapid tissue growth, including growth of glands and
vasculature (in response to estradiol)
Secretory Phase
• Days 15 – 28
• After ovulation (day 14) - corpus luteum secrets progesterone.
• Progesterone promotes endometrial maturation
• Glands become secretory
• Spiral arterioles grow and coil
- prepares for fert
• Corpus luteum atrophies
• Progesterone levels fall
• Spiral arteries contract
• Endometrial tissue breaks down and bleeding occurs
• Shed tissue and blood removed via cervix and vagina (menstruation / menses)
Secretory Phase and back to…… If fertilisation and implantation do not occur:
• Corpus luteum atrophies
• Progesterone levels fall
• Spiral arteries contract
• Endometrial tissue breaks down and bleeding occurs
• Shed tissue and blood removed via cervix and vagina (menstruation / menses)
• Ovarian/menstrual cycles occur between ___________ and
menopause
Menachy
• A cohort of follicles begin to grow in response to signals from the ___________ and pituitary – all but one of these follicles will undergo atresia.
Hypothalamus
• Secretion of large amounts of estradiol by the ___________
follicle will cause the ___________ and subsequently ovulation
and formation of the corpus luteum.
Dominant
LH surge
• The endometrium undergoes cyclic periods of growth,
maturation and breakdown in response to cyclic patterns in
___________ and ___________.
Estradiol
Progesterone
