8.0 RESPIRATORY SYSTEM: INTRODUCTION
The respiratory system comprises the following elements:
I. The air conductory region: nasal cavity, larynx, trachea and bronchial tree.
8.2 - images: Nasal cavity:
8.3 - images: Laryngeal region, with false and true vocal cords, epiglottis.
Depending on the physical pression the areas are covered with ciliated pseudostratified epithelium or with stratified squamous epithelium. The larynx is build with cartilaginous plates (thyroid, cricoid arytenoid) which are kept together with dense collagenous ligaments. Seromucinous glands are present as well as striated intrinsic muscles of the larynx.
See: POJA-L330+331 and POJA-L432+332+333
See: 8.3 - POJA-L336+337+338+340+341 and 8.3 - POJA-L336+335 and 8.3 - POJA-L334A
8.4 - images: Trachea
The trachea is rendered rigid by incomplete circular 15-20 hyalin cartilage rings, closed by a dense fibrocollagenous ligament. The trachea is lined by pseudostratifies ciliated columnar epithelium and goblet cells. Sero mucous tracheal glands are present in the submucosa
See: 8.4 - POJA-L342+343 and 8.4 - POJA-L346+347+348 and 8.4 - POJA-L-350+351
II. The distal respiratory region:
8.5 - images: Lung
The final air-conductory bifurcation are called terminal bronchioles which proceed into respiratory bronchioles lined by cuboidal ciliated epithelium.
See: Bronchus and bronchioli: 8.5 - POJA-L358+354+360+356 and 8.5 - POJA-L362+369 and 8 - 5 POJA-L363+364 and POJA-L364+366+365
See: Lung parenchym: POJA-L443
O2/gaseous -exchange takes place in the alveoli of the alveolar sacs (air sacs), lined by pneumocytes type I, pneumocytes type II and alveolar macrophages. The flattened pneumocytes I attribute to the air-blood barrier with the interalveolar capillaries. The pneumoctes II produce the surfactant needed to facilitate the gaseous exchange. The macrophages are found both in the free alveolar space and in the interstitial tissue. The alveolar wall is rich in elastin fibers to facilitate the the movement upon inhalation and expelling of the air in the lung parenchym (in the local absence of cartilage).
See : 8.5-POJA-L381+447+439 and 8.5-POJA-L382+400+385+386 and 8.5-POJA-L420+419 and 8.5-POJA-L426+ao and 8.5-POJA-L437+387+384
8.6 - images: Development of the lung
Lung histogenesis: The lung tissue develops from the median diverticle alimentary tract as a gland (glandular period). After the 4th month the canalicular period starts by dichotomy of "tubes" or conductory canals. After seven months the alveolar period starts with the development of the alveoli.
See: 8.6-POJA-L 403+404+405 and 8.6-POJA-L410+411+412 and 8.6-413+424+414 and 8.6-POJA-L415+416
and POJA-L461+462+463
8.7 - images: Pathology
Squamous metaplasia/dysplasia: See: 8.7-POJA-L 446+448+449+450
Lung emphysema: See: POJA-L472+453 and POJA-L475 and POJA-L474+473
I. The air conductory region: nasal cavity, larynx, trachea and bronchial tree.
8.2 - images: Nasal cavity:
- Vestibulum nasi, with a transition from keratinizing stratified epithelium (skin type) into non-keratinizing squamous epithelium and further into respiratory epithelium (ciliated columnar epithelium, pseudostratified). Scattered between the respiratory epithelial lining goblet cells (mucus secretion) are present. Apocrine glandulae vestibulares are located in the submucosa, as well as sebaceous glands. Mucus, amylases and lysozyme are products of these glands.
- Nasopharynx, is lined by columnar epithelium and stratified squamous epithelium towards the oro-pharynx region. A nasopharyngeal tonsil (adenoids) is present. The Eustachian tube from the middle ear open into its lateral walls.
- Olfactory mucosa in the roof of the nasal cavity with a highy specialized receptor epithelium (pseudostratified) and Bowman's glands. The olfactory receptor cells are bipolar neurons, with an olfactory vesicle with cilia at the surface top. The axonic end (fila olfactoria) connect to the olfactory bulb of a cranial nerve. The serous Bowman glands liquid dissolve and wash odorous substances. The area with the olfactory epithelium is called "conchae nasales superiores".
8.3 - images: Laryngeal region, with false and true vocal cords, epiglottis.
Depending on the physical pression the areas are covered with ciliated pseudostratified epithelium or with stratified squamous epithelium. The larynx is build with cartilaginous plates (thyroid, cricoid arytenoid) which are kept together with dense collagenous ligaments. Seromucinous glands are present as well as striated intrinsic muscles of the larynx.
See: POJA-L330+331 and POJA-L432+332+333
See: 8.3 - POJA-L336+337+338+340+341 and 8.3 - POJA-L336+335 and 8.3 - POJA-L334A
8.4 - images: Trachea
The trachea is rendered rigid by incomplete circular 15-20 hyalin cartilage rings, closed by a dense fibrocollagenous ligament. The trachea is lined by pseudostratifies ciliated columnar epithelium and goblet cells. Sero mucous tracheal glands are present in the submucosa
See: 8.4 - POJA-L342+343 and 8.4 - POJA-L346+347+348 and 8.4 - POJA-L-350+351
- Bronchial tree, as a continuation of the trachea have the same architecture. The bronchial epithelium contain tall columnar ciliated cells with scattered intermediate cells, goblet cells, neuroendocrine cells. and basal cells. The submucosa of the bronchial tree contains variable amounts of smooth muscles and seromucous glands. Bronchi contain some cartilage, Bronchioloi, however, lack cartilage.
II. The distal respiratory region:
8.5 - images: Lung
The final air-conductory bifurcation are called terminal bronchioles which proceed into respiratory bronchioles lined by cuboidal ciliated epithelium.
See: Bronchus and bronchioli: 8.5 - POJA-L358+354+360+356 and 8.5 - POJA-L362+369 and 8 - 5 POJA-L363+364 and POJA-L364+366+365
See: Lung parenchym: POJA-L443
O2/gaseous -exchange takes place in the alveoli of the alveolar sacs (air sacs), lined by pneumocytes type I, pneumocytes type II and alveolar macrophages. The flattened pneumocytes I attribute to the air-blood barrier with the interalveolar capillaries. The pneumoctes II produce the surfactant needed to facilitate the gaseous exchange. The macrophages are found both in the free alveolar space and in the interstitial tissue. The alveolar wall is rich in elastin fibers to facilitate the the movement upon inhalation and expelling of the air in the lung parenchym (in the local absence of cartilage).
See : 8.5-POJA-L381+447+439 and 8.5-POJA-L382+400+385+386 and 8.5-POJA-L420+419 and 8.5-POJA-L426+ao and 8.5-POJA-L437+387+384
8.6 - images: Development of the lung
Lung histogenesis: The lung tissue develops from the median diverticle alimentary tract as a gland (glandular period). After the 4th month the canalicular period starts by dichotomy of "tubes" or conductory canals. After seven months the alveolar period starts with the development of the alveoli.
See: 8.6-POJA-L 403+404+405 and 8.6-POJA-L410+411+412 and 8.6-413+424+414 and 8.6-POJA-L415+416
and POJA-L461+462+463
8.7 - images: Pathology
Squamous metaplasia/dysplasia: See: 8.7-POJA-L 446+448+449+450
Lung emphysema: See: POJA-L472+453 and POJA-L475 and POJA-L474+473
COPYRIGHTS
All rights reserves worldwide for the POJA collection are hold by L.G. Poels and P.H.K. Jap and Radboud University Medical Center (Radboud UMC Nijmegen). No one may modify, copy, distribute, transmit, display, or publish any materials contained in the POJA collection without prior written permission of the authors Poels and Jap or the UMC St Radboud. Any commercial use of the POJA collection is forbidden. POJA images are partly deposited in the Health Education Assets Library (HEAL database) as well as in the MedEdPortal/AAMC database).
All rights reserves worldwide for the POJA collection are hold by L.G. Poels and P.H.K. Jap and Radboud University Medical Center (Radboud UMC Nijmegen). No one may modify, copy, distribute, transmit, display, or publish any materials contained in the POJA collection without prior written permission of the authors Poels and Jap or the UMC St Radboud. Any commercial use of the POJA collection is forbidden. POJA images are partly deposited in the Health Education Assets Library (HEAL database) as well as in the MedEdPortal/AAMC database).