Developmental Aspects of Lung Disease Flashcards
What is morphogenesis?
The origin and development of morphological characteristics
What is morphology?
Branch of biology dealing with the study of the form and structure of organisms
What are the stages of lung morphogenesis?
1) Embryonic (3-8 weeks)
2) Pseudo-glandular (5-17 weeks)
3) Canalicular (16-26 weeks)
4) Saccular (24-38 weeks)
5) Alveolar (36 weeks - 2/3 years)
When is the embryonic stage of lung morphogenesis?
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3-8 weeks
When is the pseudo-glandular stage of lung morphogenesis?
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5-17 weeks
When is the canalicular stage of lung morphogenesis?
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16-26 weeks
When is the succular stage of lung morphogenesis?
24-38 weeks
When is the alveolar stage of lung morphogenesis?
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36 weeks - 2/3 years
What stage of lung morphogenesis is this?
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Embryonic
What stage of lung morphogenesis is this?
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Pseudo-glandular
What happens to the alveoli after birth?
They continue to seperate
How many alveoli are there at birth compared to at 3-8 years?
100-150 million at birth
200-600 million at 3-8 years
What happens to alveolar dimensions as children age?
They increase
What happens during the embryonic and pseudo-glandular stages?
Formation of major airways
Formation of bronchial tree and portions of respiratory parenchyma
Birth of the acinus
What happens during the canalicular stage?
Last generation of the lung periphery formed
Epithelial differentiation
Air blood barrier formed
What happens during the saccular stage?
Expansion of air spaces
Surfactant detectable in amniotic fluid
What happens during the alveolar stage?
Secondary seperation
When are presenting problems found?
Foetal ultrasound (75%)
Childhood (15%)
Newborn (10%)
What presenting problems are detected in a newborn?
Trachypnoea (abnormally rapid breathing)
Respiratory distress
What is trachypnoea?
Abnormally rapid breathing
What is abnormally rapid breathing called?
Trachypnoea
What problems are often detected in childhood?
Wheeze/stridor
Recurrent pneumonia (same region of the lung)
Incidental finding
What is congenital?
A disease present from birth
What is a disease present from birth known as?
Congenital
What are some common congenital lung diseases?
Tracheo-bronchomalacia
Pulmonary adenomatoid malformation
What are symptoms of tracheo-bronchomalacia?
Barking cough
Early onset
Breathless on exertion
Stridor/wheeze
What is the management of tracheo-bronchomalacia?
Airway clearance physiotherapy
Antibiotics
Avoid asthma treatment
What is trachea-bronchomalacia?
Uncommon disease of the central airways resulting from softening or damage of the cartilaginous structures of the airway walls in the trachea and bronchi
What is pulmonary adenomatoid malformation?
Usually an entire lobe of lung is replaced with is replaced with a non-working cystic piece of abnormal lung tissue
When does closure of the diaphragm occur?
About 18 weeks
What contributes to the development of the diaphragm?
Variety of primitive tissues
What are some possible diaphragm abnormalities?
Diaphragmatic hernia
Eventuation (protrusion of contents of the abdoment through a defect or weakness in the abdominal wall)
What are some possible causes of a diaphragmatic hernia?
Pulmonary hypoplasia
Persistent pulmonary hypertension
What is pulmonary hypoplasia?
Incomplete development of the lungs, resulting in a low number of bronchopulmonary segments or alveoli
What is persistant pulmonary hypertension?
Babies circulation does not change over from feotal to newborn circulation, so blood is forced away from the lungs due to high pressure in the arteries
What is eventuation?
Protrusion of contents of the abdoment through a defect or weakness in the abdominal wall
What is protrusion of contents of the abdomen through a defect or weakness in the abdominal wall known as?
Eventuation
What is a diaphragmatic hernia?
Abnormal opening in the diaphragm
What is a functional change in the lungs at birth?
Change from fluid secretion to fluid absorption
What could the change from fluid secretion to fluid absorption of the lungs at birth cause?
Transient tachypnea
What is transient tachypea?
Retained foetal lung fluid
What is transient tachypnea associated with?
Caesarean section delivery
How long does it take for transient tachypnea to resolve?
24-48 hours
What is surfactant?
Detergent made from phospholipids and lipophillic proteins
What are the functions of surfactant?
Stabolises alveoli and promotes gas exchange
What is surfactant secreted by?
Type II pneumocytes
What do type II pneumocytes contain that allows them to secrete surfactant?
Lamellar bodies which are secretory organelles
What are lamellar bodies?
Secretory organelles
What is an example of a neotatal lung disease caused by surfactant deficiency?
Hyaline membrane disease (RDS)
What is hyaline membrane disease?
The same as respiratory distress syndrome, caused by a deficiency of surfactant
What is hyaline membrane disease also known as?
Respiratory distress syndrome
What is the treatment of hyaline membrane disease?
Antenatal glucoricoids
Surfactant replacement
Supportive
What is chronic neonatal lung disease?
General term for persistant respiratory problems in premature babies
What is chronic neonatal lung disease also known as?
Bronchopulmonary dysplasia or CLD prematurity
What are some of the possible causes of chronic neonatal lung disease?
Antenatal infection
Barotrauma/oxygen toxicity
Patent ductus arteriosus (PDA)
Genetic
What is barotrauma?
Physical damage to bodies due to the pressure difference of gases inside and outside it
What is patent ductus arteriosus (PDA)?
Ductus arteriosus fails to close after birth
What does chronic neonatal lung disease increase the chances of?
Childhood respiratory morbidity
Future risk of COPD
What is morbidity?
The condition of being diseased
What are some antenatal origins of adult lung disease (COPD)?
In utero nicotine exposure
Foetal infection
Maternal nutrition
Low birth weight/prematurity
Maternal macronutrients/vitamins
What are some post-natal origins of adult lung disease (COPD)?
Infection
Growth
ETS (environmental tobacco smoke)
Envrionmental pollution
Macronutrient/vitamins
What is remodelling?
Alteration of structure following an external influence
What are examples of remodelling due to pre-natal nicotine exposure?
Lung hypoplasia
Reduced alveolarisation
Reduced lung function
Increased susceptability to infection
Interference of inter-cellular signalling
What is lung hypoplasia?
Incomplete development of the lungs, resulting in low numbers of bronchoplumonary segments or alveoli
What are examples of remodelling due to asthma?
Chronic inflammation
Increased bronchial responsiveness
Increased mucuc secretions
Airway oedema
Airway narrowing
What are examples of remodelling due to chronic neonatal lung disease (CNLD)?
Chronic inflammation
Interference of inter-cellular signalling
Treatment toxicity
What is CNLD?
Chronic neonatal lung disease
What is this curve called and what does it tell us?
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Fletcher peto curve, which tells us the damage from smoking is irreversible, but the decline can be slowed by stopping
What cause of death is COPD?
3rd leading cause of death in the world
What leads to remodelling of the airway/lung parenchyma?
Antenatal programming
Environmental exposure
Gene interactions
What does low lung function at birth increase the risk of in later life?
COPD