QuestionSBA
QuestionChoice
After 26 weeks the developing lungs enter the terminal sac stage. This is where the alveoli develop, comprised of type 1 pneumocytes (which are simple squamous epithelial cells) and type 2 pneumocytes (which are cuboidal cells that produce surfactant). As the foetus in the clinical vignette is only at 22 weeks gestation, its lungs are yet to have developed alveoli.
10025795
a
Development of the alveoli
QuestionChoice
Formation of the respiratory diverticulum occurs during the embryonic stage of lung development at 3-6 weeks gestation. The respiratory diverticulum forms in the foregut endoderm. As the foetus in this question is at 22 weeks gestation they will have undergone this stage, making this option incorrect.
10025797
c
Formation of the respiratory diverticulum
QuestionChoice
The development of the bronchial tree occurs in the pseudoglandular stage of lung development. This occurs between 8-16 weeks gestation and involves multiple differentiations of the bronchial buds to form a primitive bronchial tree. As the foetus in this question is at 22 weeks gestation they will have undergone this stage and thus have developed a bronchial tree, making this option incorrect.
10025796
b
Development of the bronchial tree
QuestionChoice
Formation of parietal and visceral pleura occurs during the embryonic stage of lung development from around 5 weeks gestation. The pleura is developed from the mesoderm. As the foetus in this question is at 22 weeks gestation they will have undergone this stage, making this option incorrect.
10025798
d
Formation of parietal and visceral pleura
QuestionChoice
The mesoderm is one of the germ cell layers of the embryoblast. Following implantation the primitive streak appears in the epiblast and helps form new layers: firstly the endoderm and then the mesoderm, leaving the original layer of hypoblast cells (now known as the ectoderm). This occurs around weeks 2-3 of gestation. As the foetus in this question is at 22 weeks gestation they will have already undergone formation of the mesoderm, making this option incorrect.
10025799
e
Formation of the mesoderm
Concept
Chapter
2693
4533
Development of the lungs
Topic
171
Embryology
17557
A 32 year old female patient presents to her GP with concerns about her pregnancy. She is currently 22 weeks pregnant and has had all of her routine checks without issue. However, she is concerned because a friend gave birth prematurely and the baby had to have "help to breathe". She is keen to learn more about foetal lung development.

Which of the following stages of lung development is the foetus still yet to undergo?
a