reproductive: PREGNANCY Flashcards
(140 cards)
when and where does spermatogenesis begin?
- begins at puberty
- occurs in seminiferous tubules
how spermatogenesis start at puberty ?
sex cords in testes develop a lumen that become seminiferous tubules
SOS #n #c in spermatogenisis and oogenesis with time period and stages :)))
A- 2n 2c diploid
-males: SPERMATOGONIA (at puberty)
-females: OOGONIA (divide in utero)
(both derived from primordial GERM CELLS)
—-—> DNA synthesis
B- 2n 4c diploid
-males: PRIMARY SPERMATOCYTES
-females: PRIMARY OOCYTE (arrest in meiosis I prophase until puberty)
———>meiosis I
C- 2 (1n 2c) haploid
-males: SECONDARY SPٍِERMATOCYTE
-females: a-SECONDARY OOCYTE (at menstrual cycle, note: other primary oocytes become polar bodies and degenerate)
—-—> meiosis II
MALES: 4 (1n 1c) haploid : SPERMATIDS: 4 haploid gametes result—> then: undergo SPERMIOGENESIS!!!
to form: sepermatozoa (sperm)
FEMALES:
no fertilization: oocyte degenerates (NO MEIOSIS II)
fertilization: COMPLETES MEIOSIS II to form OVUM 1 (1n 1c) haploid
what is spermiogenesis?
how is it done? 4 steps
formation of spermatozoa (from spermatids)
1-formation of ACROSOME: cap of sperm (contains enzymes to assist in fertilization)
2-condensation of nucleus
3-formation of neck and tail
4-shedding of most of cytoplasm
sertoli cells and leydig cells and spermatogonia
- location and function?
- how is it stimulated?
sertoli cells -line walls of seminefrous tubules -support/regulate spermatogenesis -stimulated by FSH leydig cells -interstitium (between tubules) -secrete testosterone -stimulated by LH spermatogonia -behind blood-testis barrier (separated from tubule by sertoli cells)
relation between sertoli cells and leydig cells in spermatogenesis
leydig cells release testesterone (stimulated by LH) which acts in a a PARACRINE manner to support sertoli cells (stimulated by FSH)
what cells form the BLOOD-TESTIS BARRIER? what type of junctions and why are they important? and describe both sides (apical/basal)
-sertoli cells
-tight junctions b/w adjacent sertoli cells
(isolate sperm, protection from autoimmune attack)
-apical side (toward tubule): meiosis and spermiogenesis
-basal side: spermatogonia cell division
what hormones are needed for normal spermatogenesis?
FSH, LH,….???
FSH
LH
function of placenta
1- nutrient
2- gas exchange
what is a decidual reaction
endometrium rxn at implantation
what are the 2 membranes that surround the fetus in utero?
1- AMNION (inner membrane)
holds amniotic fluid
2- CHORION (surrounds amnion/embryo)
derived from trophoblast
basal plate vs chorionic plate
of the placenta
basal plate (maternal side)
-includes maternal decidua basalis
chorionic plate (fetal side)
-give rise to chorionic villi
what layer of the blastocyst develops into placenta
outer layer: trophoblast
2 cell layers of trophoblast?
both together form what?
1- syncytiotrophoblast (outer)
- invades endometrium
- villi
- form lacunae (spaces) for maternal blood
2- cytotrophoblast (inner)
- proliferates, thus cells migrate into (1)
- secretes proteolytic enzymes to aid invasion
they form the chorionic villi
chorionic villi function and layers
contact area with maternal blood: digestive tract (nutrients) and resp organ (gas exchange)
- outer: syncytiotrophoblast
- inner: cytotrophoblast
how does the chorionic villi connect to the umbilical cord
fetal MESODERM invades villi,
branches of umbilical artery/vein grow :)
placental circulation
- maternal side
- fetal side
maternal
1- endometrial spiral arteries
2- villous space
3- endometrial vein
fetal
1-umbilical arteries (deoxy)
2- chorionic arteries
3- capillaries
4- capillaries
5- umbilical vein (oxy)
placental barrier
- oxygen co2?
- glucose?
- a.a?
- abs?
- diffusion
- facilitated
- active
- only IgG
umbilical cord is derived from mother or fetus? what parts ?
only FETUS
derived from:
1- yolk sac
2- allantois
what is the allantois?
what does it become?
what happens to it later?
- outpouching from wall of gut
- walls form umbilical blood vessels
- lumen occludes in development: become URACHUS: fibrous remnant: connects bladder to umbilicus
umbilical cord consists of
2 umbilcal arteries (deoxy)
1 umbilical vein (oxy)
-wharton jelly (contains mucopolysaccharides- similar to vitreous humor)
-allantoic duct (connects fetal bladder to umbilical cord) obliterates-urachus
what fetal anomalies are associated with single umbilical artery
1- aneuploidy
2- congenital malformations
what is a remnant of allantois ?
connects what?
becomes what?
may cause ?
urachus
- bladder and umbilical cord
- in adult: median umbilical ligament
- may cause ADENOCARCINOMA of bladder
urachus anomalies 3
1- patent urachus urine discharge from umbilicus 2- vesicourachal diverticulum diverticulum of bladder 3-urachal cyst partial obliteration fluid filled cavity —> infection risk