L1, Conducting Portion-1 - Respiratory System PDF

Respiratory system Conducting portion of respiratory system (1) Issue 1/ 2018 Code: OSM 2-1 b Issue 1/ Code: OSM 2-1 b 2018 Issue 1/ Code: OSM 2-1 b 2018 Issue 1/ Code: OSM 2-1 b 2018 Code of conductEffe...

Respiratory system Conducting portion of respiratory system (1) Issue 1/ 2018 Code: OSM 2-1 b Issue 1/ Code: OSM 2-1 b 2018 Issue 1/ Code: OSM 2-1 b 2018 Issue 1/ Code: OSM 2-1 b 2018 Code of conductEffectiv e interact ion Switch off Mutual mobile respect phones Smile Appreci Struggl ate our e to be differen on time ces Focus on topic Issue 1/ Code: OSM 2-1 b 2018 Intended learning outcomes By the end of the lecture, the students will be able to: Name the two portions of respiratory system Describe the histological structure of vestibule & nasal fossae of nasal cavity Identify the site and structure of olfactory epithelium Differentiate between olfactory & respiratory epithelium Recognize the histological structure of paranasal sinuses & nasopharynx Describe the microscopic structure of epiglottis & vocal cords Enumerate & describe the layers of the wall of the trachea Code: OSM 2-1 b  Content Portions of respiratory system Nasal cavity: vestibule & nasal fossae Olfactory epithelium Paranasal sinuses Nasopharynx Larynx: epiglottis, vocal cords Trachea Issue 1/ 2 Code: OSM 2-1 b 2018  Respiratory System Site of Cond exchange uct of gases air to between the air and lung blood Cleans, warms, humidif ies Alveoli Issue 1/ 1 Code: OSM 2-1 b 2018  NASAL CAVITY Super ior conch Middle a concha Inferior concha Issue 1/ 1 Code: OSM 2-1 b 2018  NASAL CAVITY Vestibule Nasal fossae - Vibrissae - Lateral wall → 3 (filters large conchae particles). - ↑surface area - Keratinized & create stratified turbulence. squamous epithelium → Non-keratinized Code: OSM 2-1 b  Nasal fossae  Respiratory epithelium EXCEPT superior concha and roof Vestibule → Olfactory epithelium.  CT corium contains muco- serous glands and large venous plexus. Code: OSM 2-1 b  Olfactory epithelium “Modified respiratory epithelium” - Thicker. - Yellow in colour. - No goblet cells. - Immotile cilia. - Serous gland in its CT corium (Bowman’s gland) Code: OSM 2-1 b Issue 1/ 1 Code: OSM 2-1 b 2018  Olfactory I- Olfactory mucosa II- lamina propria epithelium 1-Sensory cells. 2-Suporting cells. 3-Stem cells. Code: OSM 2-1 b  I- Olfactory 1. Sensoryepithelium cells (olfactory neurons): - Bipolar nerve cells - Dendrite: end by olfactory swelling, with long non-motile cilia (↑ surface area) - Axon: form olfactory nerve 2. Supporting (sustentacular) cells: - Columnar cells with wide apex & narrow base. - Microvilli on upper surface - Contain yellow pigment. 3. Stem (Basal) cells: (darkly Code: OSM 2-1 b  II- Lamina propria Fibroelastic CT. Contains Bowman’s gland → serous (watery) fluid → Solvent for odorous substances. Issue 1/ 1 Code: OSM 2-1 b 2018  PARANASAL SINUSES  Frontal, maxillary, ethmoidal & sphenoidal. - Lined by Respiratory epithelium but → Thinner, few goblet cells, few glands & adherent to Issue 1/ 1 Code: OSM 2-1 b 2018  NASOPHARYN X - Between nasal cavity & oropharynx. - Lined by Respiratory epithelium. - Contains Pharyngeal tonsil. Code: OSM 2-1 b  LARYNX - Voice production - Lined by Respiratory epithelium - Mainly Hyaline cartilage. Issue 1/ 1 Code: OSM 2-1 b 2018  Epiglottis  Elastic cartilage Anterior surface → stratified squamous epithelium Posterior surface → respiratory epithelium Ant Post Issue 1/ 1 Code: OSM 2-1 b 2018  Vocal Cords 1- False vocal cords Protection of airways Respiratory epithelium 2- True vocal cords Voice production ligament Non-keratinized St. Sq. muscle epith. Vocal ligaments at the edges. Vocal muscles (skeletal Code: OSM 2-1 b  TRACHEA - 12 cm long tube. - 20 C-shaped hyaline cartilage rings.  Cartilage → keep it patent  Incomplete → allow distention of esophagus during swallowing. Code: OSM 2-1 b Rings are closed posteriorly by: v  Fibroelastic ligament → prevent over distention  Trachealis muscle → Issue 1/ 2018 allow constriction of 1 Code: OSM 2-1 b Layers of the wall of trachea: Mucosa: a.Pseudostratified columnar epithelium with goblet cells & motile cilia (respiratory epithelium) b.Lamina propria: loose 2018CT. Issue 1/ 1 Code: OSM 2-1 b Layers of the wall of trachea: 2. Submucosa: - Loose CT with mucoserous glands & lymph follicles. 3. Fibro-cartilaginous coat: - C-shaped hyaline cartilage rings - Closed posteriorly by Issue 1/ 1 Code: OSM 2-1 b 2018 Layers of the wall of trachea Code: OSM 2-1 b  Respiratory system: conducting and respiratory portions Nasal cavity: vestibule (hairy stratified squamous epithelium, and nasal fossae with 3 conchae) Inferior and middle conchae → respiratory epithelium Superior concha → olfactory epithelium (sensory, supporting, stem cells) Paranasal sinuses, nasopharynx & larynx → respiratory epithelium EXCEPT vocal cords & anterior surface of epiglottis → stratified squamous epithelium Wall of trachea: Mucosa (respiratory epithelium), submucosa, fibrocartilaginous coat ( C-shaped cartilage rings), adventitia. Code: OSM 2-1 b Issue 1/ Code: OSM 2-1 b 2018 Test your knowledge 1. Olfactory epithelium is differentiated from respiratory epithelium by: a. Simple columnar ciliated b. Presence of microvilli c. Absence of goblet cells d. Lining the inferior concha 2. Justify: e. Presence of incomplete cartilage rings in the wall of trachea f. Presence of vibrissae in vestibule of nose Code: OSM 2-1 b Issue 1/ Code: OSM 2-1 b 2018 References Junqueira’s Basic Histology Text & Atlas Wheater's Functional Histology: A Text and Colour Atlas. www.histology-world.com www.bluehistology.com www.lumen.com Issue 1/ 1 Code: OSM 2-1 b 2018 Issue 1/ Code: OSM 2-1 b 2018