2017 Group Project 5

From Embryology
2017 Student Projects 
Student Projects: 1 Cerebral Cortex | 2 Kidney | 3 Heart | 4 Eye | 5 Lung | 6 Cerebellum
Student Page - here is the sample page I demonstrated with in the first labs.I remind all students that you have your own Group Forum on Moodle for your discussions, it is only accessible by members of your group.
Editing Links: Editing Basics | Images | Tables | Referencing | Journal Searches | Copyright | Font Colours | Virtual Slide Permalink | My Preferences | One Page Wiki Card | Printing | Movies | Language Translation | Student Movies | Using OpenOffice | Internet Browsers | Moodle | Navigation/Contribution | Term Link | Short URLs | 2018 Test Student

Lungs

An introduction to the lungs...

On this page, we will be exploring the development of the lungs through the stages of embryonic growth.

Lung Anatomy

Lung Histology

Developmental origin overview

Brief overview of development of lung

More detailed overview in lung development stages

The Respiratory Zone

The Terminal Bronchioles

Alveolar ducts

Alveoli

The Conducting Zone

The Lung Development Stages

Stage
Description
Embryonic (weeks 4-5)
About
Pseudoglandular (weeks 5-17)
About
Canalicular (weeks 16-25)
About
Saccular (weeks 24-40)
About
Alveolar (week 36-8 years)
About

Developmental timeline

Stage
Development
"'Historical Discoveries'"
Embryonic (weeks 4-5)
The Embryonic stage is the first stage of lung development. It is identified by the emergence of lung buds in the ventral wall of the foregut; these lung buds will later divide to form lobar divisions. The endoderm is responsible for the epithelium of the lung buds which will later differentiate into specialised respiratory epithelium. The mesoderm is responsible for the mesenchyme surrounding the lung buds.
Christian Pander, Karl Ernst von Baer, and Heinrich Rathke were among the first to use a new wave of technology in embryology; involving the use of new staining techniques and improved microscopy. Their findings together identified the presence of primary germ layers (ectoderm, endoderm and mesoderm) and the development of early organs. [1]
Pseudoglandular (weeks 5-17)
about
history
Canalicular (weeks 16-25)
about
history
Saccular (weeks 24-40)
about
history
Alveolar (week 36-8 years)
about
history

Structure of respiratory network

Physiologically, the organ can be divided into two parts:

The Conducting system – consists of all tubular structures including the larynx, trachea and bronchi. (image)

The Functional unit – An alveolus containing specialised epithelial cells where gas exchange occurs.

By week 8 of development, the lungs are in the development of the pseudoglandular stage (refer to developmental timeline). The three germ layers formed in gastrulation all contribute to the development of the lung, including signalling for a cascade of events as well as branching of the bronchioles.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3787747/bin/rsob-3-130088-g6.jpg

Developmental signalling processes

Chemicals involved in the development of lungs. Growth factors that contribute to branching of lungs - SHH and fibroblast growth factor as well as any other hormones or factors that are relevant to lung development

The development of a mammalian lung is a multi-step and highly complex process involving signalling pathways.

Several growth factors and chemical signals have been identified to influence lung development. These signalling molecules include:

1. Fibroblast Growth Factor (FGF10) - serves as a signalling cue for epithelium outgrowth in the mesenchyme.

2. Sonic Hedgehog (SHH) - produced in the epitheliumand is involved in regulating FGF10 expression, leading to the intertubular mesenchyme to facilitate growth and formation of epithelial buds.

3. Heparan Sulfate Glycosaminoglycans (HS-GAG) - interacts with SHH in order to produce epthelial cells and lung morphogenesis. There is still a lack of understanding in the role that HS plays in mammalian lung development.



The conducting system

Branching of lungs Different types of branching - domain branching, planar bifurcation, trifurcation, orthogonal bifurcation.

The mammalian lung develops through branching morphogenesis.

Alveolus: the functional unit

How the alveoli work. Cell types Maturation and development Surfactant - where cells are derived from (macrophages, type 1 and type 2 pneumocytes) Lungs become fully developed within the mother, however they do not function until birth.

At the end of the conducting system, are sac-like structures known as alveoli, which are assist in gas in exchange.



Current understandings and areas of research

include any relevant articles

Review and research articles

Movies

Animal models

Abnormal development

Premature Birth

Lobar Emphysema

Congenital Diaphragmatic Hernia

Azygos lobe

Meconium Aspiration Syndrome

Newborn Respiratory Distress Syndrome

Surfactant Metabolism

Bronchopulmonary Dysplasia

Lung Agenesis

Cystic Fibrosis

CHAOS (Congenital High Airway Obstruction Syndrome)

CPAM (Congenital Pulmonary Airway Malformation)

Lung Cardiovasculature

Future questions

Glossary

References

  1. Gilbert SF. Developmental Biology. 6th edition. Sunderland (MA): Sinauer Associates; 2000. Comparative Embryology. Available from: https://www.ncbi.nlm.nih.gov/books/NBK9974/