Developmental aspects of lung disease Flashcards
During growth and development of the lung, what processes/systems are needed for healthy lungs?
Morphogenesis
Surfactant system
Postnatal lung growth
Abnormalities of growth and development of the lung leads to…
Congenital lung disease
Hyeline membrane disease
The stages of lung morphogenisis are?
Embryonic Pseudo-glandular Canalicular Saccular Alveolar
Embryonic stage happens when?
3-8 weeks into gestation
Pseudo-glandular stage happens when?
5-17 weeks
Canalicular stage happens when?
16-26 weeks
Saccular stage happens when?
24-38 weeks
Alveolar stage happens when?
36 weeks and continues on for roughly 2 to 3 years
In what stage of lung morphogenesis does the larygo-tracheal groove grow forward to form the primitive trachea?
Embryonic
Gas exchange becomes possible towards the end of the BLANK stage.
Canalicular
What can be seen in the pseudo-glandular stage?
Major airway abnormalities
Small airways
Increased branching
Blood vessels a large distance from airways
What happens to the blood vessels in the Canalicular stage?
Move closer to allow gas exchange
As the alveolar stage of lung morphogenesis continues, the number of alveoli…
Increases
The continuation of alveolar separation in postnatal lung growth allows for…
A larger surface area to allow gas exchange
Expansion of air spaces occurs in which stage?
Saccular
When is surfactant detectable in amnionic fluid?
Saccular stage - ~24 weeks
In the embryonic stage, what structural abnormalities can be seen that point to congenital lung disease?
Stenosis (narrowing) of the tracheal/laryngeal
Pulmonary agenesis
Tracheo-oesophageal fistula
What does agenesis mean?
The failure of an organ to develop during embryonic growth due to the absence of primordial tissue.
What is a fistula?
An abnormal passage between a hollow or tubular organ and the body surface, or between two hollow or tubular organs.
What abnormalities can be seen in the pseudoglandular stage that point to congenital lung disease?
Pulmonary sequestration
Cystic-Adenomatoid malformation
Cyst formation
What does congenital mean?
A condition existing at or before birth
What is a pulmonary sequestration?
When a piece of lung tissue isn’t attached to the pulmonary arterial blood supply, so isn’t connected to the normal bronchial airway architecture, and fails to contribute to respiration
What are the two common diaphragmatic abnormalities?
A diaphragmatic hernia A eventration (where most of diaphragm is raised)
What functional changes occur in the lungs at birth?
Change from fluid secretion to fluid absorption Pulmonary vasodilatation
What can happen in a newborn baby whose lungs haven’t transitioned from fluid secretion to absorption?
Tachypnoea (rapid breathing)
Function of surfactant in the lungs?
Stabilises alveoli
Promotes gas exchange
What does surfactant deficiency cause?
Neonatal lung disease - hyeline membrane disease
Chronic neonatal lung disease is suspected to lead to what diease in children in adult life?
COPD
What can lead to adult COPD in the antenatal stage of a childs life?
In utero nicotine exposure Low nutrition
Micronutrients and vitamins
Low birth weight/prematurity
What can lead to adult COPD in the post-natal stage of a childs life?
Infection (Barker hypothesis) Growth ETS (+/- 1 AT deficiency) Environmental pollution Micronutrients/vitamins
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People with normal, healthy lungs will experience decreased lung function when?
With age
Accelerated decline in lung function can be seen in what type of patient?
Smokers
Premature babies
Children exposed to second hand smoke Children who have experienced lung insult
If long term smokers quit smoking, will there be any effect on their lung function?
Lung function will still decrease faster than that of a non-smoker, but will improve compared to those who keep smoking
COPDs main cause is?
Heavy smoking
Low lung function at birth increases the risk of developing what?
COPD
