1 Embryology/Histology Flashcards
What are the 3 stages of development of the embryo?
- early development (fertilization-day 16)
- Embryonic period (weeks 3-8)
- Fetal period (week 9-38)
Most organ systems are susceptible to damage during the ____________ period
embryonic
What body parts are most susceptible during the fetal period?
CNS (brain, ear, eye)
palate+teeth
external genitalia
Describe the genetic makeup of daughter cells in mitosis vs meiosis.
Mitosis: daughter cells are clones
Meiosis: crossing over (pachytene of meiosis I) creates genetically different daughter cells
Meiosis in females results in __________ while meiosis in males results in __________
ONE ovum (and 3 polar bodies)
4 spermatids
By week 12 of a female embryo, her Oogonia halt during _________ phase and are now known as _____________
halt @ PROPHASE I
known as PRIMARY OOCYTE
Primary oocytes are diploid _______
4N (have 4 copies of each chromosome)
Simple squamous covering+primary oocyte= ?
Primordial follicle
the capsule of the primordial follicle is composed of what?
simple squamous epithelium (Follicular cells)
Once puberty begins, __________ automatically begin to grow a cuboidal capsule around the primary oocye
primordial follicles
When we have a Primary follicle, it begins secretion of a glycoprotein coat around the oocyte called?
zona pellucida
The change from squamous cells to cuboidal cells gives it the name ____________ follicle
Primary Follicle (unilaminar)
Upon conversion from a Multilaminar Primary Follicle to a Vesicular Follicle, what happens inside?
accumulation of fluid (Antrum)
duh, ‘vesicle’ means bladder
A vesicular follicle has an outer CT layer. What’s it called?
theca externa (fibrous capsule)
theca interna (will become steroid cells)
When does this oocyte that’s been stuck in Prophase I for years ever get to complete its FIRST meiotic division?
-FSH SURGE
The presence of a Secondary Oocyte tells us the oocyte has done what?
completed its first meiotic division
The FSH SPIKE causes the primary oocyte within the Vesicular Follicle to do 2 things. What are they?
- complete the FIRST meiotic division
- as it divides, oocyte moves into the ANTRUM
Now that the secondary oocyte is floating in the antrum, what are we ready for?
OVULATION bitchesssssss
Ovulation occurs when the follicle is pushed to the surface of the ovary and what 3 things are squirted out
secondary oocyte (duh)
liquor folliculi (fluid in antrum)
cumulus oophorus cells (clumps of follicular cells)
After squirting out the secondary oocyte thru the peritoneum, the ruptured follicle becomes the ?
corpus luteum (yellow body)
What the hell is the function of the corpus luteum?
it secretes Progesterone, which MAINTAINS THE UTERINE ENDOMETRIUM
If progesterone levels are not sufficient, what happens to the endometrium?
it sloughs off (i.e. during MENSES)
To go from a Primary follicle to a secondary Follicle, we require ?
FSH (not spike)
A female presents with complete Anterior Pituitary insufficiency. Her menstrual cycle has stopped due to cells not being able to progress past a ______________
Primary follicle
FSH is REQUIRED for primary to secondary conversion
What is the name for a very swollen vesicular follicle near ovulation?
Graafian follicle
At what stage of meiosis does the Secondary Oocyte halt after stimulation by FSH?
halts @ Metaphase II
stays in METaphase II until its MET a sperm
What rhythmically beats to encourage uptake of the secondary oocyte into the fallopian tubes?
fimbriae of the infundibulum of the fallopian tube
Cells of the __________ become DHEA secreting after ovulation.
theca interna
What prevents degeneration of the Corpus Luteum?
implantantion of the embryo into the endometrium causes release of hCG which tells the Corpus Luteum to KEEP GOING BRAHHH WE’VE GOT A BABY SEEEEE
How long does the corpus luteum last if implantation occurred?
5 months (but only necessary for 1st trimester)
Who takes over the job of the dying corpus luteum?
Placenta
Who is the bouncer for the oocyte?
zona pellucida (only lets ONE cool sperm in)
The most internal follicular cells around the primary oocyte eventually are called ____________ which produce ________
-granulosa cells
make ESTROGEN
Once FSH told a primary follicle to become a secondary follicle, what is produced which prevents further follicles from becoming secondary?
ESTROGEN (gives negative feedback on FSH, LH)
A Primary Oocyte is found in what types of follicles?
Primordial, Primary, and Secondary
A Secondary Oocyte is found in what types of follicles?
just the Graafian follicle
Inhibin is produced by what cells, and what’s its function?
granulosa cells
acts as negative feedback for FSH
