Conception & Fetal Development Flashcards
Somatic cells determines
physical characteristics
somatic cells
Þ 46 chromosomes; 23 pairs (23 from mom, 23 from dad)
Genotype
genetic makeup of an organism (makeup of an individuals that is made up of genes from generations (passed down to different generations))
Phenotype
observable expression of gene (physical characteristics of an organism)
dominant
Describes a trait that covers over, or dominates, another form of that trait.
Recessive
An allele that is masked when a dominant allele is present (need two copies of allele to be present for it to be expressed)
Monosomy
instead of 46 pairs, the baby has 45 pairs
Trisomy
47 pairs (one extra pair of chromosomes)
multi-factoral disorder
2 distinguished form of defects
o EX: spina bifida and heart defect
Turner Syndrome
A chromosomal disorder in females in which either an X chromosome is missing, making the person XO instead of XX, or part of one X chromosome is deleted.
Klinefelter syndrome
A chromosomal disorder in which males have an extra X chromosome, making them XXY instead of XY.
gamete
specialized cell involved in sexual reproduction
Ovulation
The process of releasing a mature ovum into the fallopian tube each month
when does conception occur?
when Ovum (egg) and sperm become united
A membrane encloses the fertilized egg and sperm, the membrane is called
zona reaction
Fertilization takes place in
ampulla of fertilized tube then it goes to uterus
implantation occurs
in 6-10 days after conception this happens (this can cause bleeding/spotting)
decidua
the thick layer of modified mucous membrane that lines the uterus during pregnancy and is shed with the afterbirth.
ovum from
conception to dAy 14
when is it considered an embryo
Þ day 15 to 8 weeks after conception
After 8 weeks, the embryo becomes a
fetus
what is the most crutial part of development
8 weeks
Spermatogenesis
production of sperm
Oogenesis
Egg production
amniotic fluid
derived from fluid by diffusion from maternal blood at first then at 11 weeks the baby urinates to increase amniotic fluid
yolk sac
The yolk sac is an extra-embryonic membrane that provides food for the embryo.
umbilical cord
a tube containing the blood vessels connecting the fetus and placenta
oligohydramnios
too little amniotic fluid (<300mL)
Polyhydraminos
excessive amniotic fluid >1500mL
Functions of amniotic fluid
maintain baby body temperature, provided oral fluids, place wastes, fluid and electrolyte homeostasis, free movement and cushion fetus from trauma, and acts as a barrier to infection, allows to help lung maturity
how many vessels are in the umbilical cord
3 VESSELS: 2 ARTERIES; 1 VEIN
the umbilical cord is surrounded by
Þ Wharton’s jelly (protects the 2 arteries and one vein)
Þ Twists spirally
true knot
baby movement can form a knot and baby could die
uchal cord
Umbilical cord around the fetal neck.
when is the placenta made
on implementation (6-10 days after conception)
functions of the placenta
hormone and enzyme production, nutrient and gas exchange, remove waste from fetus
Three shunts in fetal circulation
ductus venosus, foramen ovale, ductus arteriosus
ductus arteriosus
moves blood from pulmonary artery to aorta
o Closes within 24 hours of birth
ductus venosus
high O2 blood from liver to inferior vena cava to right atrium
o Closes 2-3 months and has no function
foramen ovale
bypasses the lungs and moves blood from right atrium to left atrium
o Closes immediately after birth
week 4 development
- Heart: 2 chambers, valves, and speta forming
- Circulation beginning (heart beating 65 BPM)
o At the end of week 3 they heart begins to beat, starts off very slowly
Week 5 development
AT RISK FOR ANOMALIES IS HIGHEST TO THIS POINT
week 8 development
- First indication of bone ossification
o MOM SHOULD TAKE EXTRA CALCIUM, otherwise mom may get cavity or tingling of hands and feet
when is the heart beat audible with a doppler
12 weeks development
when does meconium, begin to collect in the intestines
16 week development
when do the sebaceous glands begin to secret vernix
20 week development
When does mom start to feel fetal movement
20 weeks (multigravid can feel it at 16 weeks)
When is the placenta fully formed?
20 weeks
viability
viable at 24 weeks (can be as early at 22 with technology)
when does the baby begin to hear and respond to sound inutero
24 weeks
When does lecithin form in alveolar surface
28 weeks
RATIO FOR LUNG MATURITY IN BABY
2:2.5 (L/S RATIO)
Dizygotic
Þ : two mature ova (eggs) are released and two DIFFERENT sperm with fertilize the eggs (they look nothing alike because its two eggs with two separate sperms)
Dizygotic placenta
o They will have two separate placentae, but they can be joined in the middle
Monozygotic
Þ one egg (ovum) release and one sperm that fertilized one egg but then it DIVIDES INTO TWO (this is identical twins of the same sex)
Monozygotic placenta
o One big placenta with two umbilical cords
Conjoined
monozygotic, but something went wrong during division and they may share one body.
Triplets
could be two eggs and one divides or one egg dividing three times.
