Developement Of Respiratory System Flashcards
When does the lung bud grow downwards & backwards from the oesophagus?
The 4th week
What cells line the terminal alveolar sacs?
Type 1 alveolar epithelial cells
What’s the other name for lung bud?
Respiratory diverticulum
What is of endodermal origin?
Epithelia of internal lining of Larynx, trachea, bronchi, lungs
What is of mesothelial origin?
Cartilage, muscle & CT of trachea & lungs
What is a fistula?
An abnormal connection between 2 structures
What week do the bronchi begin to form?
Week 5
Define ‘Atresia’
Absence of a normal body passage or cavity
Stenosis
Narrowing of passage
When do the Lung buds expand into the body cavity, forming pleura?
Weeks 5 & 6
Name the narrow channels either side of the foregut, that are gradually filled by the expanding lungs?
Pericardioperitoneal canals
How many tertiary bronchi are in the R & L lung?
R = 10
L = 8
Where us the bifurcation of the trachea by birth?
At the level of 4th thoracic vertebrae
Name the 4 stages of lung development?
Pseudoglandular
Canalicular
Saccular
Alveolar
When is the Pseudoglandular stage?
5-16 weeks
When is the Canalicular stage?
16-26 weeks
When is the Saccular stage?
26-term
When is the Alveolar stage?
> 36 weeks
What shape are the cells lining the respiratory bronchioles?
Cuboidal
What makes up the blood air barrier?
Epithelial cells & capillaries
What do fetal breathing movements result in before birth?
Aspiration of amniotic fluid
Stimulates lung development
What produces surfactant?
When do these develop?
Type 2 alveolar cells
At the end of the 6th month
Define ‘Telectasis’
When surfactant remains deposited as a thin phospholipid coat on the alveolar membranes, as fluid is resorbed from alveolar sacs.
Oligohydramnios
Insufficient amniotic fluid within the lungs.
Causes pulmonary hypoplasia as fluid in lungs stimulates lung growth.
