2014 Group Project 1
|2014 Student Projects|
|2014 Student Projects: Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | Group 6 | Group 7 | Group 8|
|The Group assessment for 2014 will be an online project on Fetal Development of a specific System.
This page is an undergraduate science embryology student and may contain inaccuracies in either description or acknowledgements.
- 1 Respiratory
- 1.1 Introduction
- 1.2 Current Research, Models and Findings
- 1.3 Historic findings
- 1.4 Abnormalities
The lungs intake oxygen and remove carbon dioxide from the body. This process is owing to the respiratory system. The development of the respiratory system commences during the embroynic and fetal stages. The embryonic stage is the first 1-8 weeks and anything after that till about week 37 or birth is the fetal stage. The fetal stage of the development of the respiratory system is what we aim to explain.
The respiratory system consist of the Conducting zone and the Respiratory zone lets look at this further.
5 stages of take place when the lungs develop;
Embryonic stage - week 4-5
Pseudoglandular stage - week 5-17
Canalicular stage - week 16-25
Saccular stage - week 24-40
Alveolar stage- late fetal to 8 years of age
Current Research, Models and Findings
Physiological factors in fetal lung growth
This article looks at the current findings of different physiological factors that affect normal neonatal, functioning lungs upon during fetal development. The size of the paired organ to be able to exchange carbon dioxide with oxygen for the very first time at birth, is crucial to be able to withstand that pressure. As we know surfactant, is a lipid-protein composite. It is crucial to the function of the neonatal lung because:
A. Its high viscosity and low surface tension stabilize the diameter of the alveoli and prevent their collapse after each expiration.
B. Because the alveoli remain partially open, they are expanded on inspiration with much less expenditure of energy. [ANAT 2241 LEC 11-Respriation]
However, current research suggests that the production of surfactant which is reliant on hormonal factors, have little influence on fetal lung growth. In contrast, the following physiological lung growth factors were found to permit the lungs to express their inherent growth potential.
[this will be looked at further as the research project progresses]
Lung morphogenesis revisited: old facts, current ideas
Classical ideas -4 basic rules vs their review
Genetic control of lung development
Current concepts of lung development
Effects of hormones on fetal lung development
The fetal respiratory system as target for antenatal therapy
1. <pubmed>23431607</pubmed> Comparison between historical and current literature in regards to the development of the respiratory system
2. Developmental Biology, 6th edition By Scott F Gilbert. Swarthmore College Sunderland (MA): Sinauer Associates; 2000. ISBN-10: 0-87893-243-7
- Links: | Developmental Biology
Comparative embryology with detail on historical understandings of early respiratory development observed in various species. Accessible through PubMed.
3. Human Embryology and Morphology, 1902 By Arthur Keith London: Edward Arnold.
Historical images of past understandings on respiratory development
4. YouTube Video explaining early respiratory development
Newborn Respiratory Distress Syndrome (Hyaline Membrane Disease)
Newborn Respiratory Distress Syndrome (NRDS), also known as Hyaline Membrane Disease is characterised by the lack of or inability to synthesise surfactant in the premature lung of neonates.
The incidence of NRDS occurs in babies suffering form immature lung development, usually from premature birth with increased severity and incidence in correlation to decreased gestational age . Preterm births do not allow for full lung maturation of the preterm infant due to process in which the respiratory system forms (from upper respiratory tree to lower). Type II Pneumocytes secrete surfactant into the alveoli, reducing surface tension and thus preventing the collapse of the alveolus – they are the last respiratory cells to differentiate. Preterm infants usually lack Type II Pneumocytes in their lung tissue causing the instability of their alveoli, oedema from immature alveolar capillaries and hyaline membrane formation.
NRDS mostly occurs in preterm neonates but can occur in post-term and term babies for a variety of reasons including:
- Intrauterine Asphyxia – commonly caused by wrapping umbilical cord around the neck of the neonate, impairing development
- Maternal diabetes – high levels of insulin can delay surfactant synthesis
- Multiple pregnancy (twins, triplets etc) – associated with high rates of preterm births and resulting lung immaturity 
- Rapid labour, fetal distress, placenta previa, preeclampsia, placental abruption – that impair lung maturation in final stages of pregnancy 
- Preterm Caesarean delivery – not allowing for lung maturation
- Genetic abnormalities that impair surfactant synthesis (ABCA3)
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Congenital Diaphragmatic Hernia
- Down-regulation of sonic hedgehog expression in pulmonary hypoplasia is associated with congenital diaphragmatic hernia.
- Computer simulation analysis of normal and abnormal development of the mammalian diaphragm.
- Outcomes of congenital diaphragmatic hernia: a population-based study in Western Australia.
- Congenital diaphragmatic hernia.
- Bronchopulmonary Dysplasia.
- Surfactant Metabolism Dysfunction and Childhood Interstitial Lung Disease (chILD).
- Evaluation of fetal vocal cords to select candidates for successful fetoscopic treatment of congenital high airway obstruction syndrome: preliminary case series.
- The epidemiology of meconium aspiration syndrome: incidence, risk factors, therapies, and outcome.
- Antenatal infection/inflammation and postnatal lung maturation and injury.