NM705 EXAM 1 QUESTIONS AND ANSWERS WITH COMPLETE
SOLUTIONS VERIFIED LATEST UPDATE
What are the 5 stages of fetal lung development?
1. Embryonic
2. Pseudoglandular
3. Canilicular
4. Saccular
5. Alveolar
What are the important milestones achieved during the Canilicular period of fetal
lung development?
Occurs during week 16-25. Acini (functional units of lung) form. Air-blood barrier forms.
Lungs become highly vascular setting the stage for gas exchange *Lungs become
potentially viable at the end of this stage due to beginning of surfactant
synthesis*
What are the important milestones achieved during the Saccular period of fetal
lung development?
Occurs during week 25-36. Terminal saccules elongate, branch and widen. Air-blood
barrier thins.
*By end of this stage all bronchioles are formed*
What are the important milestones achieved during the Alveolar period of fetal
lung development?
, Occurs from 36 weeks gestation-8 years old. Folding and dividing of saccular epithelium
form alveolar septa. At birth 50-150 million alveoli are present. Gas exchange becomes
more efficient.
Describe basic fetal cardiac development and the most critical timeframe for this
development:
Major heart structures are completed by 8 weeks post conception. Most heart defects
arise during weeks 4-8 of gestation.
What are some biochemical factors that stimulate baby to take its first breath?
-mild asphyxia
-temperature changes
-Epithelial sodium channels (ENaCs) shifts the fluid out of the alveoli
-Increase in catecholamines and cortisol to stimulate reabsorption of the fluid during
labor
-the lungs change from a secretory body to an absorbing body
-Carbon dioxide helps initiate the baby to take its first breath
What are some mechanical factors that stimulate baby to take its first breath?
-tactile, light noise and proprioceptive stimuli greater than ever experienced
-thoracic recoil with the birth of the torso
-Foramen ovale closes due to decreased umbilical blood flow, decreased venous return
from IVC, decreased right atrial pressure and increased left atrial pressure
-Squeezing of the thorax during birth also expels some fluid from the upper airway
- Pressure gradient changes from a high pulmonary system to a low system making
pulmonary resistance low
SOLUTIONS VERIFIED LATEST UPDATE
What are the 5 stages of fetal lung development?
1. Embryonic
2. Pseudoglandular
3. Canilicular
4. Saccular
5. Alveolar
What are the important milestones achieved during the Canilicular period of fetal
lung development?
Occurs during week 16-25. Acini (functional units of lung) form. Air-blood barrier forms.
Lungs become highly vascular setting the stage for gas exchange *Lungs become
potentially viable at the end of this stage due to beginning of surfactant
synthesis*
What are the important milestones achieved during the Saccular period of fetal
lung development?
Occurs during week 25-36. Terminal saccules elongate, branch and widen. Air-blood
barrier thins.
*By end of this stage all bronchioles are formed*
What are the important milestones achieved during the Alveolar period of fetal
lung development?
, Occurs from 36 weeks gestation-8 years old. Folding and dividing of saccular epithelium
form alveolar septa. At birth 50-150 million alveoli are present. Gas exchange becomes
more efficient.
Describe basic fetal cardiac development and the most critical timeframe for this
development:
Major heart structures are completed by 8 weeks post conception. Most heart defects
arise during weeks 4-8 of gestation.
What are some biochemical factors that stimulate baby to take its first breath?
-mild asphyxia
-temperature changes
-Epithelial sodium channels (ENaCs) shifts the fluid out of the alveoli
-Increase in catecholamines and cortisol to stimulate reabsorption of the fluid during
labor
-the lungs change from a secretory body to an absorbing body
-Carbon dioxide helps initiate the baby to take its first breath
What are some mechanical factors that stimulate baby to take its first breath?
-tactile, light noise and proprioceptive stimuli greater than ever experienced
-thoracic recoil with the birth of the torso
-Foramen ovale closes due to decreased umbilical blood flow, decreased venous return
from IVC, decreased right atrial pressure and increased left atrial pressure
-Squeezing of the thorax during birth also expels some fluid from the upper airway
- Pressure gradient changes from a high pulmonary system to a low system making
pulmonary resistance low
