chapter 1 fetal lung development Flashcards
what are the fetal lung development requirements
adequate surface area, pulmonary vascular systems ability to transport blood through the lungs, structure and elasticity
stages of lung development
embryonal pseudoglandular canalicular saccular alveolar
how long is the embryonal stage
week 1 - 8
when is the pseudo glandular stage
week 8-16
what lung developments occur during the pseudo glandular stage
conducting airways develop, pattern of lung structure is formed, cilia goblet cells, and mucus glands are formed, the epiglottis and the membrane that separates oropharnx is formed
when is the canalicular stage
week 17-26
what stage does fetal viability occur in and what week
canalicular stage week 22
what is developed (lungs) during week 20-22
type 1 and II epithelial cells, immature surfactant, and smooth muscle in conducting airways
when is the saccular stage
week 27 - 35/36 weeks & post term
when are alveoli seen
week 32
what occurs in the lungs during the saccular stage
alveoli epithelium and pulmonary capillaries merge, alveoli increase in number and size, mature surfactant
what occurs during alveolar stage
at birth alveoli are 20-150 million, and continue development up to age 8 increasing in size until growth of chest wall is complete
what factors affect lung growth
hypoxia, starvation, hyperoxia
what is pulmonary hypoplasia
lack of alveoli, not enough airways, olighydramnios (not enough amniotic fluid)
what can cause pulmonary hypoplasia
diaphragmatic hernia
what is the function of type I cells
allows for gas diffusion, and used as a barrier against water and solute leakage
what is the function of type II cells
surfactant production, storage and secretion
what is surfactant made up of
pc, pg, neutral lipids, and proteins
what law describes surfactant and what is its purpose
lap laces law; and to lower surface tension
when is surfactant inhibited
hypoxia, hypothermia, acidosis
how much fluid does fetal lungs secrete
250-300 ml per day
when are fetal lungs filled with fluid
cannicular period until delivery
what purpose does amniotic fluid serve
prevents traumatic injury, thermoregulation, fluid movement
