conception & fetal development

humans have __ chromosomes, __ paired autosomes and _ sex-specific pair

46; 22; 1

which parent determines the sex of the baby?

male

once an ovum is fertilized, a ______ develops

zygote

how long is an ovum fertile once expelled from the ovary?

24 hours

how long can sperm remain viable?

2-3 days

how does a sperm penetrate an ovum?

ovum protective coating is removed by enzymes in the sperm head

where does fertilization happen?

outer middle fallopian tube (ampulla)

what is it called when a woman is pregnant in an area outside the uterus?

ectopic pregnancy

at 16 cells, the zygote is called…

morula

what is a blastocyst? what will it become

an inner cell mass that forms from the morula; embryo and amnion

what are trophoblasts? what will it become?

outer cell layer of morula; chorion and placenta

after fertilization, a morula forms after _ days and implantation occurs at _ days

3; 6

fingerlike projections on the zygote are called…

chorionic villi

where does implantation typically occur?

anterior or posterior fundus of the uterus

chorionic villi function

oxygen and nutrient exchange from mom to fetus

what is the corpus luteum? what does it produce?

where the egg was released on the ovary; progesterone and HCG

what value is the best indicator for pregnancy tests?

hCG

what separates fetal and maternal blood?

a single-cell layer

where does maternal blood flow to?

chorionic villi

what allows nutrients, O2, and other substances to cross the chorionic villi and get to the fetus?

trophoblasts

where are trophoblasts located?

on the outside of chorionic villi

what does the chorion contain?

yolk sac, embryo, and amnion

what stage does organogenesis occur? (teratogens can be detrimental!)

embryonic stage

how long is the fetal stage?

9 weeks to delivery

what does the amnion contain?

embryo

oligohydramnios (low amniotic fluid level)

<300 mL

hydramnios/polyhydramnios (high amniotic fluid level)

2 L or more

sections of the placenta where the chorionic villi reside are called…

cotyledons

what hormones does the placenta produce?

hCG, hPL, progesterone, and estrogen

hCG function

preserves corpus luteum for estrogen and progesterone availability

hPL function

maternal metabolism, insulin resistance, and lactation

estrogen function

uterine growth

metabolic functions of the placenta

transfer gases, nutrients, and heat, excrete waste, and passive immunity

which hormone causes increased temp, thickened cervical secretions, and increased endometrial blood supply?

progesterone

veins in the fetal circulation contain __________ blood while arteries contain ____________ blood

oxygenated; deoxygenated

what surrounds the vessels of the umbilical cord?

whart'on’s jelly

nuchal cord

umbilical cord wrapped around the fetal neck

umbilical vein function

brings oxygenated blood through the cord to the fetus

ductus venosus function

from IVC through liver to placenta delivering oxygenated blood

ductus arteriosus function

carry blood away from the lungs and send it out to the body

foramen ovale function

carry blood away from the lungs and send it out to the body

umbilical arteries function

carry deoxygenated blood from the fetus to the mom

why do fetal structures of circulation obliterate after birth?

change in pressure in heart and lungs

at how many weeks does the double-chambered heart beat?

4

at how many weeks can the sex be determined?

12

at how many weeks can the fetus hear?

24

at how many weeks can the kidneys secrete urine?

12

at how many weeks do the eyelids open?

24

at how many weeks does the inner ear develop?

8

at how many weeks do the testicles descend?

30

at how many weeks is sucking present?

12

only immunoglobulin to cross placenta giving passive immunity to the fetus

IgG

immunoglobulin in breastmilk giving the baby passive immunity

IgA

how many lunar months is pregnancy and how many weeks is a lunar month?

10; 4

pre-embryonic stage is how many weeks?

2

embryonic stage is how long?

day 15 to 8th week

fetal stage is how long?

8th week to delivery

viability definition (also at how many weeks and what weight)

when fetus can survive outside the uterus, 20 weeks, 350-500 g

ear malformation → inspect what organ?

kidneys

cleft lip → inspect what organ?

heart for septal defects

dizygotic vs monozygotic

fraternal two eggs and separate sacs, identical one egg divided one chorionic sac