Respiratory System - Upper Respiratory Tract
The respiratory system does not carry out its physiological function (of gas exchange) until after birth. The respiratory tract, diaphragm and lungs do form early in embryonic development. The respiratory tract is divided anatomically into 2 main parts: 1. upper respiratory tract, consisting of the nose, nasal cavity and the pharynx; 2. lower respiratory tract consisting of the larynx, trachea, bronchi and the lungs.
In the head/neck region, the pharynx forms a major arched cavity within the phrayngeal arches. The lungs go through 4 distinct histological phases of development and in late fetal development respiratory motions and amniotic fliud are thought to have a role in lung maturation.
Development of this system is not completed until the last weeks of Fetal development, just before birth. Therefore premature babies have difficulties associated with insufficient surfactant (end month 6 alveolar cells type 2 appear and begin to secrete surfactant).
Some Recent Findings
- Human Embryology Larson Chapter 9 p229-260
- The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud Chapter 12 p271-302
- Before We Are Born (5th ed.) Moore and Persaud Chapter 13 p255-287
- Essentials of Human Embryology Larson Chapter 9 p123-146
- Human Embryology Fitzgerald and Fitzgerald Chapter 19,20 p119-123
- Anatomy of the Human Body 1918 Henry Gray 1. The Respiratory Apparatus
Upper Respiratory Tract
- part of foregut development
- anatomically the nose, nasal cavity and the pharynx
- the pharynx forms a major arched cavity within the pharyngeal arches
The animations below allow a comparison of early and late embryonic lung development. Compare the size and relative position of the respiratory structures and their anatomical relationship to the developing gastrointestinal tract.
|Early embryo (stage 13)
3 dimensional reconstruction based upon a serial reconstruction from individual Carnegie stage 13 embryo slice images.
|Late embryo (stage 22)
3 dimensional reconstruction based upon a serial reconstruction from individual embryo slice images Carnegie stage 22, 27 mm Human embryo, approximate day 56.
- Links: Flash Movies
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Cite this page: Hill, M.A. (2020, February 25) Embryology Respiratory System - Upper Respiratory Tract. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Respiratory_System_-_Upper_Respiratory_Tract
- © Dr Mark Hill 2020, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G