Respiratory System Lecture LSM2212 PDF

The Respiratory System LSM2212 Daniel Teh,...

The Respiratory System LSM2212 Daniel Teh, Assistant Professor Departments of Ophthalmology & Anatomy, Yong Loo Lin School of Medicine, Department of Biomedical Engineering, College of Design & Engineering, Neurobiology Programme, Life Sciences Institute, Center for Innovation & Precision Eye Health, National University of Singapore Email: [email protected] Tel: 6516 6824 Fundamentals of Anatomy and Physiology. Pearsons © Copyright National University of Singapore. All Rights Reserved. 1  Learning outcomes Able to appreciate the overall functions of the respiratory system. Identify & describe the anatomical organization of the upper (nose, paranasal sinuses, nasal cavity, pharynx) & lower respiratory tracts (larynx to alveoli). Recognize & describe the function of cells associated with the respiratory system and the mucosa. Understand the circulatory & lymphatic systems in the respiratory system. List the structural organization of the rib-cage & appreciate the anatomical organization of the pleura, diaphragm, intercostal muscles and rib cage. © Copyright National University of Singapore. All Rights Reserved. 2  Anatomical positions – sometimes used to describe tissues or organs locations © Copyright National University of Singapore. All Rights Reserved. 3  Functions of the Respiratory system Respiration (supplies oxygen, removes carbon dioxide – sufficient area for gaseous exchange) Ventilation of the lungs. Providing oxygen to the body for cellular metabolism Removing excessive carbon dioxide. Conditioning of inspired air Provides large surface area & conditioning for gaseous exchange – moist and warm Phonation Olfaction sense Protects respiratory surfaces from environmental variations & pathogenic invasion. © Copyright National University of Singapore. All Rights Reserved. 4  Respiratory tract – Upper respiratory tract Nasal cavity Conditioning of the air Lateral wall (conchae and meatus) Nasal septum Nasal fossa (cavities) pseudostratified ciliated columnar epithelium cells Olfactory epithelium Nose (external vestibule) – air entry & exit point External vestibule Nasal hair (filter particulates) © Copyright National University of Singapore. All Rights Reserved. 5  Respiratory tract – Upper respiratory tract Nasal cavity Conditioning of the air Lateral wall (conchae and meatus) Concha – bony plate, increase surface for conditioning of respired air. High vascularization, why?. nosebleed Meatus – passageway Create air turbulences why? – think from a conditioning, olfaction and immune/filtering perspectives. How does the nasal cavity mucosa helps in respiration? Nasal septum – separate left & right airways, navigate air flow © Copyright National University of Singapore. All Rights Reserved. 6  Respiratory tract – Upper respiratory tract Nasal fossa/cavities Air-filled cavities Roles (believed) Decrease weight of the skull Improve resonance of the voice, Temperature insulation Conditioning inspired air (humidifying & heating) Lined with pseudostratified ciliated columnar epithelium cells Paranasal sinuses are lined with respiratory mucosa- ciliated and mucus secreting. They open into nasal cavities & are innervated by branches of trigeminal nerve (V) Frontal sinus (FS) Maxillary sinus (MS) Ethmoidal sinus (ES) Sphenoidal sinus (SS) © Copyright National University of Singapore. All Rights Reserved. 7  Respiratory tract – Respiratory epithelium Cells that line the respiratory tract Pseudostratified Ciliated columnar cells Mucous goblet cells/Mucous cells- mucin Brush cells – tuft, caveolated, multivesicular & fibrillovesicular. Presence of tuft of blunt, squat microvilli. – detect irritant. Basal cells – deep, lining of the basement membrane. Stem cells of the airway. Cuboidal, large nucleus. Hewitt, R.J., Lloyd, C.M. Regulation of immune responses by the airway Sensitive to cigarette smoke. epithelial cell landscape. Nat Rev Small granule cells – provides the Immunol 21, 347–362 (2021). https://doi.org/10.1038/s41577-020- attachment. 00477-9 © Copyright National University of Singapore. All Rights Reserved. 8  Mucosa – mucus membrane Mucociliary escalator -cilia beating to move a carpet of mucus towards the pharynx (throat). -filtration in the nasal cavities. Martini Fundamentals of Anatomy and Physiology. Pearsons © Copyright National University of Singapore. All Rights Reserved. 9  Respiratory tract – Respiratory epithelium Epithelium Lamina Propria – layer (areola tissue) supporting LP Mucosa the epithelium Mucosa consists of epithelium and Lamina Propria Mucosa glands & vessels Cartilage © Copyright National University of Singapore. All Rights Reserved. 10  Respiratory tract – Pathologies (Rhinitis & Sinusitis) Rhinitis: Excessive secretion from goblet cells, narrowing of nasal cavities, Lamina propria is Sinusitis: Inflamed lining of tissue at the edematous and infiltrated with few inflammatory sinuses (one or more) – swelling leading to cells. blocking of drainage in orifices Cigarette smoking – inhibits ciliary movement, coughing removes dust laden mucous from airway. © Copyright National University of Singapore. All Rights Reserved. 11  Can you name other respiratory conditions? © Copyright National University of Singapore. All Rights Reserved. 12  Respiratory tract – Upper respiratory tract Pharynx Musculofascial Passage between oral & nasal cavities to the larynx & esophagus in the neck. Air and food pathway (separated) Nasopharynx – pseudostratified columnar epithelial Oropharynx, Laryngopharynx- stratified squamous epithelial © Copyright National University of Singapore. All Rights Reserved. 13  Respiratory tract – Pathology Obstructive sleep apnea Obstruction of airway over over-relaxed muscle tone of the pharyngeal muscle. Causes: eg. Enlarged tongue, tonsils, obesity. Treatment: breathing gadgets, CPAP or https://www.saintlukeskc.org/health- surgery. library/continuous-positive-air-pressure-cpap# Symptoms: fatigue, daytime sleepiness, irritability, apnea © Copyright National University of Singapore. All Rights Reserved. 14  Respiratory tract – Lower respiratory tract Larynx Links the pharynx to the trachea. Musculoligamentous structure with cartilage support. – 3 cartilages form the larynx (Thyroid, Circoid, Epiglottis) Valve for lower respiratory tract (when swallowing) – epiglottis (elastic cartilage) Phonation & sound (vocal cord) – glottis (opening of the vocal cord). Thyroid cartilage – largest laryngeal cartilage (hyaline cartilage) – (adam’s apple, laryngeal prominence – just for your knowledge) Protects vocal cord – together with circoid cartilage Fundamentals of Anatomy and Physiology. Pearsons © Copyright National University of Singapore. All Rights Reserved. 15  Respiratory tract – Lower respiratory tract Vocal cord* Vestibular fold (false vocal cord) – not involved in sound production. Vocal folds (true vocal cord) Stridulating – sound production by vibration or rubbing Other cartilages in the larynx (corniculate, cuneiform) Gray’s Anatomy for Student (Elsevier) © Copyright National University of Singapore. All Rights Reserved. 16 © Copyright National University of Singapore. All Rights Reserved. 17  Respiratory tract – Lower respiratory tract Trachea (windpipe) – link from the larynx to the bronchus. Wall is strengthened by C-shape cartilage Trachealis muscle – diameter of trachea Fibroelastic ligament & smooth muscle Lined with respiratory epithelium What about the mucosa & submucosa – tracheal glands. Bifurcates into left and right primary bronchi entering the lung at the hilum. © Copyright National University of Singapore. All Rights Reserved. 18  Respiratory tract – Lower respiratory tract Bronchial tree:  Primary bronchi branches into lobar bronchi = 3 bronchi (right) and 2 in the left. (Superior, middle inferior).  Lobar bronchi branches to segmental bronchi  S – bronchopulmonary segment  Lobar & segmental – cartilages plate, smooth muscle increases  Segmental branches into bronchiole (no cartilage) then to terminal bronchioles, respiratory and finally alveoli.  Sympathetic – Bronchodilation, parasympathetic - bronchoconstriction © Copyright National University of Singapore. All Rights Reserved. 19  Respiratory tract – Lower respiratory tract Alveoli Alveolar ducts - alveolar sacs – individual alvoli Gaseous exchange (O2 & CO2) between the air and the blood. Wrapped with capillaries. Thin wall-lined with simple squamous epithelium (pneumocytes). – two types of pneumocytes I & II. Based on the shape can you describe the functions of pneumocyte I & II? Surfactant – what is it? For what? Eg. Respiratory distress syndrome © Copyright National University of Singapore. All Rights Reserved. 20  Can you name the structure? What happens during pneumonia © Copyright National University of Singapore. All Rights Reserved. 21  Respiratory tract – Lower respiratory tract (3 layers blood-air barrier) Interalveolar septum-. Capillary endothelial cells – surface tension, ACE Type I epithelial cells (pneumocytes I) – gaseous diffusion barrier Type II epithelial cells (pneumocytes II) - surfactant Interstitial Alveolar macrophage (dust cells) – engulfing microbes, debris, cancer cells. interstitium Contains small pores containing adjacent alveoli. © Copyright National University of Singapore. All Rights Reserved. 22  Respiratory tract – Pathology (Asthma) ASTHMA Medical condition that affects the ability of breathing. Parasympathetic hyperactivity - broncho- constriction. Unknown cause. Allergic or non-allergic. Common symptoms: Wheezing Shortness of breath – the lining of the airway gets inflamed, swollen and narrower. The lining also increases mucous production. Coughing Chest tightness – muscles tighten up. © Copyright National University of Singapore. All Rights Reserved. 23  Respiratory tract – Pathology (Pneumonia) Pneumonia Infection of the lung that causes fluid/pus build-up in the alveoli. Prevents effective gaseous exchange. Can be mild or fatal. Virus (eg. Covid, SARS), bacteria or fungi infection. Symptoms: Coughing Fever Breathing difficulty Treatments: Antiviral, antibiotic, oxygen therapy. https://www.nhlbi.nih.gov/health/pneumonia © Copyright National University of Singapore. All Rights Reserved. 24  Respiratory tract – Pathology (Pneumonia) Ullah, Z., Usman, M., Latif, S. et al. Densely attention mechanism-based network for COVID-19 detection in chest X-rays. Sci Rep 13, 261 (2023). https://doi.org/10.1038/s41598-022-27266-9 © Copyright National University of Singapore. All Rights Reserved. 25  Respiratory tract – Lower respiratory tract PLEURA Parietal covers the inner thoracic wall surface Visceral covers the outer surface of the lung Pleural space/cavity- serous membrane – filled with pleura fluid © Copyright National University of Singapore. All Rights Reserved. 26 © Copyright National University of Singapore. All Rights Reserved. 27  Respiratory tract – Lower respiratory tract Pneumothorax – collapsed lung, presence of air in the pleural cavity. © Copyright National University of Singapore. All Rights Reserved.  Respiratory tract – Lower respiratory tract Hydrothorax – Pleural effusion. Fluid accumulation in the pleural cavity. Hemothorax –Presence of blood in the pleural cavity. © Copyright National University of Singapore. All Rights Reserved.  Respiratory tract – Lower respiratory tract LUNGS Base lies on the diaphragm. Apex, base 3 borders, 3 surfaces The 3 borders— Anterior, Posterior, Inferior Cardiac notch, lingula The 3 surfaces The costal The mediastinal/medial Ddiaphragmatic © Copyright National University of Singapore. All Rights Reserved. 30  Respiratory tract – Lower respiratory tract LUNGS Oblique fissure Horizontal fissure Cardiac impression, cardiac notch Lingula Arch of aorta © Copyright National University of Singapore. All Rights Reserved. 31 © Copyright National University of Singapore. All Rights Reserved. 32  Respiratory tract – Pathologies Chronic obstructive pulmonary disease (COPD): Emphysema Chronic Bronchitis Main causes – constant irritation of the respiratory tract, eg. smoking, pollution, occupational exposure, frequent respiratory infections, rare genetic disorder alpha-1 antitrypsin deficiency. https://my.clevelandclinic.org/health/diseases/8709-chronic-obstructive-pulmonary-disease-copd © Copyright National University of Singapore. All Rights Reserved. 33 © Copyright National University of Singapore. All Rights Reserved. 34  Respiratory tract – Pulmonary circulation Two main circulation - Reoxygenation of deoxygenated blood (lung) - Right atrium-ventricle-Pulmonary artery- lung-Pulmonary vein-left atrium-left ventricle. - Reoxygenation supply to the lung & clearing of deoxygenated blood (bronchial arteries-vein) Internal Thoracic Artery/Internal Mammary Artery – breast & anterior chest wall supply Aortic Arch © Copyright National University of Singapore. All Rights Reserved. 35 © Copyright National University of Singapore. All Rights Reserved. 36  Internal Thoracic Artery/Internal Mammary Artery – breast & anterior chest wall supply Internal Thoracic Artery © Copyright National University of Singapore. All Rights Reserved. 37  Respiratory tract – Pulmonary circulation pathology Pulmonary embolism Blockage of blood supply to the lung. Usually due to blot clot dislodges from other region, eg. Leg – deep vein thrombosis. Can also be caused by fats deposit, tumor etc. Treatment: mild, severe Symptoms: shortness of breath, fainting, chest pain, light headness Complications: pulmonary hypertension, enlarged heart https://www.venousforum.org/patients/what-is-vein-disease/what-is-pulmonary-embolism/ 38 © Copyright National University of Singapore. All Rights Reserved.  Respiratory tract – Lymphatic drainage Lymphatics of lung drain into tracheobronchial nodes (lymph nodes). Along the bronchi & pulmonary vessel, through the hilum and into the posterior mediastinum. Parasternal nodes – thoracic wall, mammary gland, abdominal area © Copyright National University of Singapore. All Rights Reserved. 39  Respiratory tract – Thoracic bony cage 12 ribs Sternum Intercostal muscle Costo-chondral junction Between each rib & costal cartilage (hyaline) Primary cartilaginous joints True ribs (T1-7) False ribs (T8-12) Floating ribs (T11-12) – no costal cartilage © Copyright National University of Singapore. All Rights Reserved. 40  Respiratory muscles Primary Respiratory Muscles Diaphragm & external intercostal muscles Respiration at rest Accessory Respiratory Muscles When changing depth and frequency Fundamentals of Anatomy and Physiology. Pearsons © Copyright National University of Singapore. All Rights Reserved. 41 © Copyright National University of Singapore. All Rights Reserved. 42 © Copyright National University of Singapore. All Rights Reserved. 43  Thank you © Copyright National University of Singapore. All Rights Reserved. 44