Test 3 Flashcards
what is the last thing that develops in the fetus?
lungs
lungs develop postnatally until what age?
8-12 yo
what is a zygote?
fertilized ovum
what is an embryo
once zygote implants approx day 14
what is a fetus
week 7 to week 40
what age is the baby incapable of life outside the mother?
less than 20 weeks
what is the age of viability?
24 weeks, 50% survival rate
what is a neonate?
birth to 28 days (first month of life)
what are the phases of lung development
embryonic, pseudoglandular, canalicular, sacular, alveolar
embryonic period characteristics
week 3-6, proximal conducting airways formed, tracheal cartliage, and segmental lung buds, diaphragm develops and main organs
Pseudoglandular period characteristics
week 7-16, all conducting airways present in mini form. fetal breathing movements begin
Canalicular period characteristics
week 17-26, terminal bronchioles, lymphatics, and pulmonary circulation, respiratory bronchioles appear, and type 2 cells appear which produce surfactant
sacular period characteristics
alveoli increase in size and number, type 2 cells mature, capillaries move closer to alveoli to inc gas exchange
alveolar period characteristics
week 36-birth, gradual inc in size and number of alveoli, alveolar shape changes from shallow to cup like
Composition of lung fluid and surfactant
95% phospholipids and neutral lipids, 5-10% proteins
L/S ratio test
2:1 ratio at 35 weeks considered to have mature lungs, if 1:1 90% have resp. distress
Fetal lung maturity test
not needed for fetus >39 weeks or <32 weeks
Antenatal steroids are used for what
to accelerate lung maturity and surfactant production, given 24-34 weeks, repeated doses not recommended
what are some things that can cause accelerated lung maturity
chronic HN, preeclampsia, HELLP syndrome, placental insufficiency IUGR, prolonged rupture of membranes PROM
What can cause a delayed maturity of the lungs
maternal diabetes mellitus, Rh isoimmunization, male babies, second born twin
What are tocolytics
drugs used to inhibit uterine contractions, may prolong pregnancy for 2-7 days
What can help determine high risk neonates
previous pregnancies, previous live births, previous premature deliveries, previous miscarriage
GPA abbreviations
G=gravida (number of pregnancies), P=para (number of live births), A=abortio (number of non viable fetuses)
what is the most common medical problem encountered during pregnancy
hypertension