Lecture 20 Flashcards
What is the female gametes
Oocytes
what are oocytes
the female gametes
what does aromatase do
converts testosterone to estradiol
what converts testosterone to estradiol
aromatase
what does progesterone do
gets the body ready for pregnancy
what are the two key functions of ovaries
produces oocytes
produce reproductive hormones
Name the pathway from cholesterol to estradiol
cholesterol
progesterone
androstenedione
testosterone
estradiol
where are progestins, androgens and estrogens produced
ovarian follicles
when is estradiol most important
first half of menstural cycle
how many carbons do progestins have
21
what produces progestins
all major ovarian cell types - granulosa cells, theca cells, corpus luteum etc
progestins are most important as a product of
the corpus luteum
when are progestins most important
during luteal phase and maintenance of pregnancy
androgens are most important as a precursor for what
estradiol
how many carbons do androgens have
19
what are androgens synthesized by
follicular theca cells
corpus lueum
what is too much testosterone associated with in women
follicular atresia
follicular atresia can be caused by what
too much testosterone
what are estrogens synthesized by
follicular granulosa cells
corpus luteum
what are estrogens essential for
stimulation of follicular development
onset of puberty
etc
What is the role of FSH W
stimulates ovarian follicles to grow and produce estradiol
what is the role of LH W
stimulates testosterone production by theca cells
stimulates ovulation/secretion of steroid hormones by corpus luteum
What is the second half of the menstrual cycle governed by
LH
What is the starting point of the primordial follicle
oocyte surrounded by single layer of flattened follicular cells
What will the single layer of flattened follicular cells around the oocyte turn into
granulosa cells
what is arrested at prophase of meiosis I
primary oocyte
when does the ovary have full complement of primordial follicles
6 months
What triggers resumption of meiosis
fertilization of the ovum
what is a zygote
fertilized egg
what is the name for a fertilized egg
zygote
what is the first trigger for meiosis in W
LH surge
what is the second trigger in meiosis in W
Fertilization
is the development of the primary follicle gonadotropin dependant or independant
independant
what is aquired when the oocyte increases in size
zona pellucida
what is the zona pellucida
specialized area surrounding oocytes
what happens as the primary follicle starts to develop
oocytes get bigger - zona pellucida
granulosa cells divide/form several layers
cells glosest to growing follicles form into theca cells
Continued maturation of the follicles require what
LH and FSH
when does it stop being a primary follicle
once you see fluid in the granulosa layer
what is antrum
Fluid
why is the antrum important
it helps to carry the oocyte - when follicle ruptures, the fluid carries out the oocyte
Why can theca cells not create estradiol
they dont have aromatase
what 2 compartments does the basement membrane divide the follicles into
inner granulosa cell
outer theca cell compartment
What follicular compartment is non vascularized
inner granulosa cell
What follicular compartment is FSH responsive
inner granulosa cell
What follicular compartment is vascularized
outer theca cell compartment
what follicular compartment is LH responsive
outer theca cell compartment
what do theca cells produce W
testosterone
can theca cells make estradiol
nope - no aromatase
what happens if there is no rising FSH levels at beginning of cycle
atresia
how does a follicle become dominant
must convert an androgenic environment to estrogenic environment
What is the corpus luteum regulated by
LH
why does FSH switches to inducing receptors for LH
because the corpus luteum is only regulated by LH
why is the corpus luteum regulated only by LH
it stimulates further E and P production
Allows for LH surge
Name 4 things LH stimulates in ovulation
resumption of meiosis (extrusion of polar body 1)
P production by granulosa cells
increase in antral fluid volume
release of hydrolytic enzymes
What is the most importnat hormone once the oocyte is released
Progesterone
what are cumulus cells
tightly associated granulosa cells that surround the oocyte and help w oocyte maturation and fertilization
what does the minor FSH surge in ovulation stimulate
synthesis of hyauloronic acid
what is hyaluronic acid important for in ovulation
cumulus explansion
what is the corpus luteum composed of
Luteinized granulosa
theca cells
capillaries
What is the lifespan of the corpus luteum without pregnancy
12 days
How long is the luteal phase
12 days
What phase has the resurfacing of epithelium
proliferative
what phase includes the development of spiral arteries and uterine glands
Proliferative phase
What phase does cervical mucus become thin to allow sperm passage
Proliferative
What phase includes the thickening of whole layer due to cell growth and fluid retention
Secretory phase
What are the 2 ovarian phases
Follicular phase
Luteal phase
What day of ovarian phases does ovulation occur
14
What are the three uterine phases
menstrual
proliferative
secretory
what is produced in increasing amounts if the oocyte is fertilized (beginning day 9-13 after ovulation)
hCG
what rescuses CL until placental P can maintain pregnancy
hCG
what are the diploid stem cells in the ovaries
Oogonia
what do the oogonia produce after mitosis
Primary oocytes
what do the primary oocytes produce after meiosis I
secondary oocytes
what does a secondary oocyte produce after going through meiosis II
Ova
The surrounding cells of an oocyte are called ____ if only one layer is present
pre-granulosa cells
The surrounding cells of an oocyte are called _____ if more than one layer is present
Granulosa cells
What are the functional units of the ovary
follicles
Describe primordial follicles
have a single layer of squamound pre-granulosa cells surrounding a primary oocyte
Describe primary follicles
have a single layer of cuboidal pre-granulosa cells surrounding a primary oocyte
Describe secondary follicles
have multiple layers of granulosa cells surrounding a primary oocyte - appearance of antrum
What do primordial, primary and secondary follicles all contain
primary oocytes arrested in prophase 1
Before puberty, all developing follicles:
undergo atresia
What does the corpus luteum develop from
ruptured follicle
THE ____ is the only thing that ever resumes meosis I in females
the oocyte in the dominant follicle
How many polar bodies are made in female meiosis
3
What are the products of female meiosis 1
two haploid cells - smaller one is the first polar body, bigger is the secondary oocyte
when does the secondary oocyte arrest
metaphase II
What is produced after meiosis 2 in females
one large ovum
a tiny second polar body
What are the two phases of follicle development
Gonadotropin - independant preantral phase
Antral phase
What occurs when a primordial follicle becomes a primary follicle
squamous cells surrounding become cuboidal
oocyte gets bigger
zona pellucida forms
What occurs when a primary follicle becomes a secondary follicle
multiple granulosa cell layers form
Oocyte gets a lot bigger
What is an antrum
A large, fluid filled cavity
when does the secondary follicular stage end
when a clear liquid begins to accumulate btween the granulosa cells
when is the dominant follicle selected
the follicular phase
how long does a follicular phase last
14ish days
what is the phase in which the corpus luteum is active
luteal phase
What occur during ovulation
the ballooning ovary wall ruptures and expels the secondary oocyte
