Respiratory System & Lung Histology Outline PDF

Outline of the respiratory system & lung histology Prepared by Dr. Ahmed A. Morsi Assist. prof. of Histology & Cell Biology 0 Learning objectives By the end of this lecture, you will be able to: 1.Know th...

Outline of the respiratory system & lung histology Prepared by Dr. Ahmed A. Morsi Assist. prof. of Histology & Cell Biology 0 Learning objectives By the end of this lecture, you will be able to: 1.Know the division of the respiratory system 2.Recognize the anatomy of the lungs 3.Describe the lung microstructure 0  The Respiratory System: Divisions Anatomically, the respiratory system is divided into upper & lower respiratory tract. Functionally, it is divided into conducting & respiratory parts 0  The Respiratory System: Divisions Respiratory system is divided into two principal regions: A. Conducting portion: B. Respiratory portion 2. I Nasal cavity, (where gas exchange 3. Nasopharynx, occurs): 2 4. 3 Larynx, 1.Respiratory bronchioles, 5. Trachea, 2.Alveolar ducts, and 4 6. 5 Primary Bronchi , 3. Alveoli. 7. 6 Secondary [intrapulmonary] bronchi 8. Bronchioles, and 7 9. Terminal bronchioles. 8 0 Respiratory System 0  Divisions of The Respiratory System: 0  Larynx Connected to the trachea. Kept patent by cartilages. The larger cartilages (thyroid, cricoid, and most of the arytenoids) are hyaline. The smaller cartilages (epiglottis, cuneiform, corniculate, and the tips of the arytenoids) are elastic cartilages. 0  Trachea Flexible and mobile tube extending from the larynx into the mediastinum where it divides into two main bronchi at level of T4. It consists of C shape cartilage. It lined by respiratory epithelium 0 Posterior Anterior  Lungs Lung is cone shaped triangular organ having: – Apex – narrow superior tip – Base – inferior surface that rests on the diaphragm – Hilum –site of entrance of pulmonary and systemic blood vessels. Left lung – separated into upper and lower lobes by the oblique fissure Right lung – separated into three lobes (upper, middle, lower) by the oblique and horizontal fissures 0 Lungs Lung histology 0  ro 1. Intrapulmonary (secondary) n bronchi: c m The wall of the secondary bronchi is m composed of: m m a)Mucosa: more folded m m Epithelium: respiratory epithelium with less m m goblet cell. m h CT corium: rich in elastic fibers. b) No submucosa: c) Musclosa: complete layer of smooth muscle surrounding the mucosa. e) Adventitia: CT containing elastic fibers and irregular incomplete plates of hyaline cartilage 0 2.Bronchioles: Smaller airways (less than 1 mm) arising from successive branching of the bronchi Their wall is composed of: a) Mucosa: Epithelium: simple columnar ciliated epithelium with Clara cells. The height of the cells decreases as well as the cilia disappear distally as the bronchioles get smaller. CT corium: b) No submucosa: c) Musculosa: smooth muscle layer completely surround the lumen e) Adventitia: loose CT 0 3.Alveolar ducts: They are the free termination of the respiratory bronchioles. Their walls are completely interrupted by the opening of the alveoli. 4.Alveolar sacs: They are common spaces sharing a group of adjacent alveoli. 0 5. Alveoli: They are the structural and functional units of the lung. They are separated by interalveolar spetae and connected together through the alveolar pores (of Kohn). They are lined by 2 types of cell: a) Type I pneumocytes b) Type II pneumocytes. 0 0 Alveolar Lining  RECOMMENDED REFERENCES, WEBSITES Junqueira's Basic Histology: Text and Atlas, Thirteenth Edition 2013 ISBN-13: 978-0071780339 ISBN-10: 0071780335 Edition: 13th The histology tutor: http://www2.yvcc.edu/histology zoomer/HistologyTutorials/hi stology_tutorials.htm 0