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RT-240 Pediatrics and
Neonatology
Class #1 Embryology
Respiratory Therapy Program
Allegany College of Maryland
Cumberland, Maryland
Terminology (Fertilization)
Zygote
Gametes
Testes
Ovaries
Gametogenesis
Spermatogenesis
Oogenesis
Fertilization
Blastomeres
Morula
Erythroblast
Embryo
Amnion
Yolk sac
Trophoblast
Placenta
Chorion
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Implantation of the Morula
Endoderm
GI, mouth, pharynx, lung and liver
Ectoderm
CNS, PNS, eyes, ears, nose, and
appendages
Mesoderm
Connective tissue, cartilage, bone heart
The embryo begins to grow!
Intrauterine Life/Respiratory
Development
Two phases
Embryonic
Fetal
Embryonic stage
“primitive development stage”
1st five weeks of gestation
Pseudoglandular stage
6th-16th weeks of gestation
Dichotomous branching
Intrauterine Life/Respiratory
Development
Canalicular stage
16th week -26th weeks
Respiratory units appear at the 16th week
Terminal Sac stage
27th week – 40 weeks
Saccular 28-36 weeks
Alveolar 36-term
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Pulmonary Surfactant
Major surfactant is called lecithin
Second type of surfactant is called
sphingomyelin
Methyltransferase system
24 – 28 weeks
Phosphocholine transferase system
35th week
Amniocentesis
Amniotic fluid is removed and
analyzed…
Chromosomal matching
Lung maturity (l/s ratio)
1:1 90% RDS (Steroids)
2:1 5% RDS
1.5:1 50% RDS
Gender
Complications