What are the 5 Major Phases Of Fetal Lung Development?
5 Major Phases Of Fetal Lung Development
Phase One: Embryonic Period
The cells that form the lungs are known as endodermal cells, and they begin to differentiate into two different types: type I and type II cells. Type I cells are responsible for gas exchange, while type II cells produce surfactant, a substance that helps to prevent the lungs from collapsing after each breath.
Phase Two: Pseudo glandular Period
The bronchioles begin to form smaller air sacs called terminal sacs, which are surrounded by a network of capillaries. The type I and type II cells continue to differentiate and become more specialized, and the production of surfactant increases.
Phase Three: Canalicular Period
The type II cells continue to produce surfactant, which helps to prevent the lungs from collapsing during exhalation. The fetus begins to make breathing movements, although the lungs are still not fully functional.
Phase Four: Terminal Sac Period
The type I cells continue to differentiate and become thinner, which allows for better gas exchange. The type II cells continue to produce surfactant, which reaches its peak production around week 35 of pregnancy.
Phase Five: Alveolar Period
The type I cells become thinner and more numerous, which increases the surface area for gas exchange. The type II cells continue to produce surfactant, which helps to maintain the stability of the alveoli and prevent their collapse.
Fetal lung development is a complex and multi-phase process that begins during the first few weeks of pregnancy and continues until birth. Each phase of development is crucial for the proper formation and function of the lungs, and any disruptions to this process can lead to respiratory problems in the newborn. Understanding the major phases of fetal lung development can help healthcare professionals to identify and address any issues that may arise during pregnancy, and can help parents to prepare for the arrival of their newborn.
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