Things I don't know: Ob/gyn Flashcards
When and from what to germ cells originate?
4th week of embryonic life
endoderm of yolk sac
When/how do germ cells form primitive gonad?
6th week embryonic life
germ cells migrate to genital ridge and associate with somatic cells
What type of errors occur in older men vs. older women?
men: mitotic errors
women: chromosome errors
How does the number of sperm produced differ from the number of ova?
sperm: many millions, ongoing process after puberty
eggs: 2.5 million at birth (already have all you will make at this point), most degenerate, left with about 400 ova in reproductive years
When do oogonia
- begin meiosis I
- what phase does meiosis I arrest
- when is meiosis I complete
- what phase does meiosis II arrest
- when is meiosis II complete
- month 3 of embryonic development
- prophase: diakinesis stage (as primary oocyte)
- ovulation
- metaphase (as secondary oocyte)
- fertilization
What separates?
Are the products identical or different (ignoring recombination)?
What would be the chromosome result be if nondisjunction occurred and a trisomy child was born?
1. Meiosis I
2. Meiosis II
- homologs; different; all 3 chromosomes are different
- sister chromatids; identical; 2 chromosomes match (look at centromeric DNA that is not involved in crossing over), 1 is different
order of mitosis/meiosis
Prophase
Metaphase
Anaphase
Telophase
leptotene
1st stage prophase
chromosomes have replicated but lie on top of each other
zygotene
2nd stage prophase
homologous pairs move together and pair or synapse
pachytene
3rd stage prophase
first time you can see bivalent chromosome: CHEERLEADER pose
2 homologous chromosomes now look like a tetrad
diplotene
4th stage prophase
CROSSING OVER occurs at CHIASMATA
diakinesis
5th stage prophase
oogenesis is frozen here until ovulation
chiasmata
areas of contact between homologs allowing crossing over
metaphase
nuclear membrane disappears
spindles appear
pairs align on metaphase plate
anaphase
homologs/sister chromatids pulled apart by spindles attached to centromeres
telophase/cytokinesis
cell division
When does nondisjunction occur?
What will be the status of the chromosomes if a trisomy child is born of it?
Meiosis I
all chromosomes are different
Insl-3 (insulin-like substance 3)
produced by gonad
play role in testicular descent
If a child has streak gonads or no SRY gene (regardless if XX or XY), what will they look like?
no AMH: uterus, fallopian tubes
presents at female with no breasts or periods
Common findings in people with mullein duct abnormalities (MDA)
infertility
endometriosis
renal anomalies
When does the uterovaginal septum resorb?
9-12 weeks gestation
unicornate uterus
- uterus
- ovaries
- kidneys
- pregnancy considerations
- development of only one horn of uterus
- two
- ipsilateral (same side) renal anomalies
- pregnancy: normal outcome, preterm labor, malpresentation
uterus didelphys
- uterus
- ovaries
- kidneys
- pregnancy considerations
complete failure of duct fusion
- two: separate uteri, upper vagina (lower may be separated by septum), cervizes
- two
- renal AGENESIS
- normal, preterm
T shaped uterus
DES exposure in utero
risk for clear cell carcinoma of vagina and pregnancy loss