Respiratory Physiology L1 (Structure) - Summer 2024 PDF

2 Main function The main function of the respiratory system is to exchange oxygen and carbon dioxide between the environment and the tissues  3 Terminology Eupnea – normal rate and rhythm Ta...

2 Main function The main function of the respiratory system is to exchange oxygen and carbon dioxide between the environment and the tissues  3 Terminology Eupnea – normal rate and rhythm Tachypnea – increased respiratory rate Bradypnea – slow repiratory rate Apnea – cessation of breathing (transient) Hyperpnea – increased depth (increasing tidal volume) +/- increased rate Polypnea – rapid shallow breathing (similar to panting) Dyspnea – difficult breathing  4 Terminology Cheyne-stokes respiration – faster respirations, then slower, followed by an apneic period Biot’s respiration – faster and deeper respiration with abrupt apneic pauses Apneustic respiration – prolonged gasping inspiration, followed by short expirations  s Respiratory system structure Conducting zone - Brings air into and out the lungs Respiratory zone - Lined with alveoli where gas exchange occurs Cunningham's Textbook of Veterinary Physiology, 6th Edition  6 Conducting zone Includes nares, nasal cavity, nasopharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles https://veteriankey.com/respiratory-system/ https://criticalcaredvm.com/chronic-bronchitis-dogs-nagging-cough/ https://veteriankey.com/transtracheal-and-bronchoalveolar-washes/  7 Conducting zone http://www.howourlungswork.com/airways.html/ Humidify, warm and filter the air before it reaches the critical gas exchange region The tracheobronchial tree is lined with mucus-secreting and ciliated cells that function to remove inhaled particles https://www.sci.psu.ac.th/wp-content/uploads/2022/07/Respiratory-system-for-student.pdf https://www.sciencephoto.com/media/311161/view/bronchial-cilia-sem  8 Conducting zone Some parts (trachea and bronchi) contain cartilage – adding support to the airways, preventing them from closing. http://medcell.org/histology/respiratory_system_lab.php http://www.howourlungswork.com/airways.html  a Conducting zone The walls contain smooth muscle – changes diameter, altering resistance, leading to increase or decrease of airflow http://www.howourlungswork.com/airways.html https://www.epa.gov/asthma/what-asthma  to Conducting zone This smooth muscle has both sympathetic and parasympathetic innervation bronchoconstriction bronchodilation  n Conducting zone parasympathetic innervation – contraction M3 bronchoconstriction https://thoracickey.com/bronchodilators/ Conducting zone sympathetic response - relaxation Pre I.itforan β2 bronchodilation  13 Conducting zone fitfor iyhitpar.fi relax Cunningham's Textbook of Veterinary Physiology, 6th Edition https://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2803%2915369-X/fulltext  14 also known as Conducting zone - summary ANATOMIC DEAD SPACE (because gas exchange does not occur here) Brings air into and out the respiratory zone Humidify, warm and filter the air before it reaches the critical gas exchange region Lined with mucus-secreting and ciliated cells that function to remove inhaled particles The walls contain: Cartilage (trachea and bronchi) – adds support to the airways, preventing them from closing Smooth muscle – changes diameter, altering resistance, leading to increase or decrease of airflow  sympathetic response  β2 receptors  smooth muscle relaxation  bronchodilation  parasympathetic response  M3 receptors  smooth muscle contraction  bronchoconstriction  15 Respiratory zone Where gas exchange occurs Includes respiratory bronchioles, alveolar ducts, and alveolar sacs Cunningham's Textbook of Veterinary Physiology, 6th Edition  n Respiratory zone respiratory bronchioles – transitional structures, have cilia and smooth muscle, but alveoli occasionally bud off their walls alveolar ducts – completely lined with alveoli, no cilia, little smooth muscle, terminate in alveolar sacs, also lined with alveoli joinsarespiratorybronchiole whichisthe typeof smallest nerespiratoryzonebeginswheretheterminal bronchiole thenleadstoanalveolarductopeningintoaclusterof ronchiole which alveoli of veolusone manysmallgrape likesacsthatareattachedtoalveolarducts The Ohio State University  18 Respiratory zone OBJECTIVE: gas exchange The alveoli Pouchlike evaginations of the walls of respiratory bronchioles, alveolar ducts, and alveolar sacs Large surface Covered by capillaries Very thin walls the alveolushaselasticwallsthatallow alveolustostretchduringintakewhich increasesthesurfacearea greatly https://www.austincc.edu/apreview/PhysText/Respiratory.html forgasexchange available alveoliareconnectedtotheirneighborsbyalveolarpores pressure alveoli  q g g 19 Respiratory zone Alveoli not perfused are DEAD SPACE (alveolar dead space) https://clinicalgate.com/pulmonary-embolism-6 anatomicaldeadspace airthat'spresentintheairwaythatNEVERreachesthealveoliandtherefore NEVERPARTICIPATES INGASExchange deadspaceinvolvesairfoundwinthe alveolar thatareunabletof x alveoli Cunningham's Textbook of Veterinary Physiology, 6th Edition  20 Respiratory zone Alveolar walls are rimmed with elastic fibers and lined with two kind of epithelial cells: Type I alveolar cell (95%) mYm atakous Type II alveolar cell (5%) They are also called pneumocytes. https://ib.bioninja.com.au/standard-level/topic-6-human-physiology/64-gas-exchange/pneumocytes.html  u Respiratory zone Alveolar type I cells: Cover 95% of alveolar surface Form a tight epithelial barrier along the alveolar type II cells Extremely thin and perfectly designed for efficient gas exchange between alveolus and pulmonary capillaries Amitotic – unable to replicate peIhighlypermeabletogases Pearson Education  N Respiratory zone Alveolar type II cells: Cover 5% of alveolar surface Pearson Education Synthetize pulmonary surfactant Reduce surface tension of alveoli Prevent alveoli from collapsing Secrete cytokines Recruitment of inflammatory cells Regenerative capacity for type I and II cells Proliferate and differentiate in Type I cells Chen and Liu, Am J Physiol Cell Physiol, 2020, 319  membranes herthealveoliandcapillary get Respiratory zone intates Alveolar macrophages: - First line of cellular defense against invading respiratory pathogens. Also remove inhaled particles from the alveolus. https://www.youtube.com/watch?v=j4ZXo5w62TE Pearson Education  24 Respiratory zone - summary Where gas exchange occurs Includes respiratory bronchioles, alveolar ducts, and alveolar sacs Alveoli are pouchlike evaginations of the walls of respiratory bronchioles, alveolar ducts, and alveolar sacs, that have large surface, very thin wall, and are covered by capillaries, to facilitate gas exchange Alveoli not perfused form the alveolar dead space Alveolar walls are rimmed with elastic fibers and lined with two kind of epithelial cells: Type I alveolar cell (95%) – gas exchange Type II alveolar cell (5%) – secrete surfactant, regenerate epithelium Alveolar macrophages are the first line of cellular defense against invading respiratory pathogens. Also remove inhaled particles from the alveolus.