embryogenesis and fetal devt Flashcards
naegale’s rule
-3 months and +7 days
how many weeks
first trimester?
second?
third?
14 weeks
28 weeks
42 weeks
first 2 weeks after ovulation
fertilization
stage 1 (0-2 d)
zygote
blastomeres
stage 2 (2-4 d)
morula (12-16 cells)
4th-5th d
blastocyst (32 cells)
stage 3 & 4 (4-6 d)
zona pellucida disappears
implantation of blastocyst
embryonic period
primitive chorionic villi
third week after ovulation and fertilization
stage 5 (6-12 d)
bilaminar embryo
primary yolk sac
ectoderm
endoderm
amnionic cavity
yolk sac cavity
stage 6 & 7 (12-17 d)
well defined embryonic disk
differentiated stalk
21 d (7somites)
differentiated body stalk
1cm chorionic sac
zipper-like motion somite
22 d (17 somites)
true intervillous space
stages 10 & 12
3-4 week old embryo
8 & 12 somites (22 &23 d)
16, 27 & 33 somites ( 24-28 d)
end of stage 12 (4th week)
c-shaped curvature
arm and leg buds
CV system
primitive heart
end of 6th week
22-24mm embryo head is large heart completely formed fingers and toes are present arms bend at elbow upper lip is complete
8th week
fetal period
4cm fetus
growth and maturation
12 weeks
CRL 6-7cm ossification centers differentiated toes and fingers scattered rudiments of hair external genitalia
16 weeks
CRL 12cm
110g
genders can be determined
eye movements
20 weeks
>300g fetal movement about every minute palpate height of fetus at umbilicus downy lanugo cochlear function
24 weeks
630g wrinkled skin & fat deposition eyelashes & eyebrows canalicular period of lung devt nociceptor
28 weeks
CRL 25cm thin red skin vernix caseosa pupillary membrane disappeared 90% survival
32 weeks
CRL 28cm
1800g
36 weeks
CRL 32cm
2500g
body more rotund
wrinkled face disappear
40 weeks
CRL 36cm
3400g
term
fetus fully developed
fetal head measurement occipitofrontal? biparietal? bitemporal? occipitomental? suboccipitobregmatic?
occipitofrontal - 11.5cm biparietal - 9.5cm bitemporal - 8cm occipitomental - 12.5cm suboccipitobregmatic - 9.5cm
anterior fontanel
posterior fontanel
diamond (sagittal & coronal)
triangle (sagittal & lambdoid)
week?
fetal brain
gyral formation and prolif, diff, and migration
20-24 wks
fetal circulation
oxygenated blood, UV (ligamentum teres) > umbilicus > ductus venosus > IVC > oxy RA > foramen ovale > oxy LA > oxy in LV > heart & brain > > deoxy from IVC & SVC > deoxy RA > deoxy RV > deoxy PA > ductus arteriosus > desc. aorta > hypogastric artery > UA (umbilical ligaments) > placenta
3 shunts of fetal circulation (changes)
ductus venosus (ligamentum venosum) foramen ovale (f. close several hrs; a. fusion 1yr; atrial septum) ductus arteriosus (f. close 10-95hrs; a. close 2-3wks; ligamentum arteriosum; bet. PA & aorta)
how many times is fetal CO than that of adult?
3x
fetal hematopoiesis
yolk sac
liver
bone marrow
hgb 12g/dL at midpregnancy to 18g/dL at term
fetal erythropoiesis
fetal EPO since maternal EPO cannot cross placenta
liver
fetal blood volume
80mL/kg after cord clamping
125mL/kg at term
3 major fetal hgb
hgb F (2 gamma) hgb A (32-34wks; 2 beta) hgb A2 (mature fetus; 2 delta)
fetal coagulation factor
2, 6, 9, 10, 11, 12, 13, 3
fetal coagulation factor
2, 6, 9, 10, 11, 12, 13, 3
Ig G
16 wks
bulk at last 4 wks
Ig M
intrauterine infx
Ig A
colostrum
lymphocytes and monocytes
9 wks - liver
12 wks - blood and spleen
14 wks - leaves thymus
nervous system
24 wks - S1
birth - L3
adult - L1
rudimentary taste bud;
ACTH
7th wk
synaptic fx; flexion on neck and trunk; glucagon; insulin containing granules; leydig prod. testosterone
8th wk
squinting, opening of mouth, incomplete finger closure; swallowing; testis prod. testosterone; mullerian duct regression; cardinal ligament
10th wk
mature receptors of taste buds; detectable insulin; urine production; 50mL amniotic fluid prod. by amniotic membrane; GH & LH (13th wk); GFR <0.1mL/min
12th wk
respiration;
trypsin, chymotrypsin, phospholipase A & lipase;
loop of henle
male external genital diff. complete
14-16th wk
suck
24th wk
hears some sound
24-26th wk
eyes sensitive to ligh
28th wk
ear devt;
400mL amniotic fluid by fetal urine
midpregnancy
integration of nervous and muscular fx
3rd trimester
SI undergo peristalsis and transport glucose;
oxytocin & AVP;
thyroid hormone
10-12 wks
fetal cholesterol from?
hepatic synthesis
urine 7-14mL/d
18th wk
amniotic fluid 1000mL
36-38 wks
pseudoglandular stage (intersegmental growth)
5-7th wk
canalicular stage (respiratory bronchioles)
16-25th wk
terminal sac stage (terminal sac)
> 25th wk
alveolar stage
32 wks
surfactant
type II pneumocytes keep terminal sac from collapsing during breathing 90% lipid; 10% protein DPPC - principal active component lecithins (80% of glycerophospholipids) SP-A - major apoprotein
synthesize & store all pituitary hormone
end of 17th wk
TSH, thyroxine, TBG;
mesonephros degenerates;
female external genital diff. complete
11 wks
pronephros (first kidney)
2 wks
mesonephros (middle kidney);
uterus & tube ariase from mullerian ducts
5 wks
metanephros
permanent kidney
GFR 0.3mL/min
20th wk
urine 650mL/d
term
origin: female genital tract fallopian tube broad ligament (19th wk) urinary bladder gartner's duct ovarian ligament round ligament
female genital tract - paramesonephric duct
fallopian tube - cephalad of paramesonephric duct
broad ligament - paramesonephric duct pulled away from posterior body wall
urinary bladder - urogenital sinus
gartner’s duct - caudal of mesonephric duct
ovarian ligament - proximal of gubernaculum
round ligament - distal of of gubernaculum
