14. Embryology of the respiratory system Flashcards
What are the 4 stages from zygote to blastocyst?
- Fertilisation: ovum surrounded by sperm
- Zygote: nucleus of the sperm enters and fuses with nucleus of ovum
- Morula: ball of cells undergoing mitosis
- Blastocyst: number of cells increases leading to blastocystic cavity, cells accumulate at one end= forming an inner cell mass. Trophoblast is the layer of cell that surrounds it
Where do the zygote -> blastocyst stages happen?
Zygote will form near ovary then travel to fallopian tube to uterine cavity into endometrium = blastocyst
What is an ectopic pregnancy?
If loose cillia function and so the zygote is stuck outside the uterus
What is the chorion?
After blastocyst, 2 layers of trophoblast will form the placenta and secrete HCG to make sure endometrium doesn’t get shed
What is thalidomide?
In 1960s, people weren’t sleeping well so used a tranquiliser to alleviate morning sickness
babies were delivered with small limbs: teratogens= environmental factors caused abnormal development
Where do lungs form from?
endoderm from the foregut
What happens if the trachea doesn’t separate from the oesophagus in embryology?
Tracheosophageal fistula and oesophageal atresia
Pleuropericardial folds- flaps of body wall at the level of the primitive pericardial cavity which grow medially and fuse with the ventral surface of the foregut mesoderm.
What is the formation of the septum transversum, pleuropericardial folds, pericardioperitoneal canals and pleuroperitoneal folds?
- Septum transversum divides pericardial cavity with peritoneal (abdomen) cavity
- Pleuropericardial folds fuse with each other and divides the pericardial cavity and pleural cavities.
- Pericardioperitoneal canal was used for the pericardial and peritoneal cavities to communicate
- But the Pleuroperitoneal folds closes the pericardioperitoneal canals.
These canals will become the pleural cavities.
These canals lie dorsally to the septum transversum. They interconnect the primitive pericardial cavity and the peritoneal cavity
The pericardioperitoneal folds expand over septum transversum and fuse with each other. Separating the
the pleural cavity with the peritoneal cavity.
What is the pericardioperitoneal canal?
openings posteriorly between the primitive pericardial and peritoneal cavities
What happens from weeks 4-7 in age development of the lungs? What period is it called?
The embryonic period, lung bud forms trachea and larynx form
What is neonatal respiratory distress syndrome?
Surfactant deficiency, alveolis collapse
What is lung agenesis?
Lung buds don’t form due to insufficient mesoderm (teratogens)
What is pulmonary hypoplasia?
Incomplete development of the lung
What is diaphragmatic hernia?
Structures herniate through diaphragm into chest wall cavity
What is hiatus hernia?
Hernia in oesophagus
What are the 4 embryology stages of the development of the diaphragm?
