Respiratory System Lecture 1 2022 PDF

RESPIRATORY SYSTEM (PSL301H) Lecture 1 Anatomy and breathing Silverthorn textbook 8th ed. 533-540, 542-544 7th ed. 535-541, 544-546 Dr. Jeff Kroetsch E-mail [email protected]  Learning Objectives for...

RESPIRATORY SYSTEM (PSL301H) Lecture 1 Anatomy and breathing Silverthorn textbook 8th ed. 533-540, 542-544 7th ed. 535-541, 544-546 Dr. Jeff Kroetsch E-mail [email protected]  Learning Objectives for the PSL301 Respiratory Section Goal – to understand… 1. The basic science of the respiratory system 2. How the respiratory system integrates with other systems 3. How dysfunction leads to disease To achieve this we will: Overview of the respiratory system Understand: Respiratory function and adaptation to different demands Consider: Blood gas content in a changing internal environment Understand: Pressure vs. volume in the breathing cycle and partial pressures Lecture 1 – Anatomy and breathing 1. What are the functions of the respiratory system? 2. What are the structures of the respiratory system? 3. How is blood transported to and from the lungs? 4. What protects the respiratory system from pathogens? 5. How is lung function measured? Why doesn’t this thing need lungs?  What are the 4 functions of the respiratory system? ons of the respiratory system? Functions: 1. Transfer of gases between air and blood 2. Regulation of body pH 3. Defense from inhaled pathogens 4. Vocalization Figure 17-1 What are the structures of the respiratory system? What structures make up the respiratory system? Figure 17.2a The respiratory muscles Respiratory muscles ~Figure 17.2 Pleural sacs enclose the lungs Pleural sacs enclose the lungs Figure from Martini (2006) Fundamentals of Anatomy and Physiology Figure 17.2 The airways connect the external to the internal environment Airways Larynx Warm air to 37 C Humidify Conditionsto air:100% Filter (nose Warms and air to 37C The trachea Trachea respiratory cilia) branches Humidifies air to 100% Into two primary bronchi. Filters air (with nose and respiratory cilia) Left primary bronchus The primary bronchus Secondary divides 22 more times bronchus terminating in a cluster of alveolei. Bronchiole Alveoli Figure 17.2e  The cilia that line the airways filter away pathogens Filtering action of cilia that line airways Cilia move mucus to pharynx Dust particle Mucus layer traps inhaled particles. Watery saline layer allows cilia to push mucus toward pharynx. Cilia Goblet cell secretes mucus. Nucleus of columnar epithelial cell Basement membrane Ciliated epithelium of the trachea mmune cells secrete antibodies disable pathogens ~Figure 17.5 Immune cells secrete antibodies and disable pathogens Airways have a tree-like architecture Functions: to distribute air to large surface area of alveoli and lower air velocity so air exchange has enough time The primary lobule is the region of gas exchange Approximately 300 million alveoli, each about 300 μm in diameter Total cross-sectional area is enormous, at about 180 cm2 Air velocity is nearly 0 The alveoli Alveoli Type II Bronchiole alveolar cells Bronchial artery, Branch of nerve and vein pulmonary artery Type I alveolar cells Elastic fibers Modified from https://ohiostate.pressbooks.pub/vethisto/chapter/1 Branch of Lymphatic 0-respiratory-tract-gas-exchange/ pulmonary vessel vein Capillary beds Alveoli Figure 17.2f Alveolar gas exchange occurs through passive diffusion Alveolar gas exchange occurs via by passive diffusion Figure 18.3  Blood transportation to and from the lungs How is blood transported to and from the lungs? High flow 10% blood volume Low pressure 25/8 mmHg Heart (right ventricle) pulmonary trunk pulmonary arteries pulmonary arterioles capillaries pulmonary venules pulmonary veins heart (left atrium) Recall: blood flow in the right side of the heart Blood flow in heart pulmonary artery from right ventricle to lungs pulmonary veins from lungs to left Right atrium atrium Right ventricle Left ventricle Figure from Martini (2006) Fundamentals of Anatomy and Physiology Clinical snapshot: Pulmonary congestion in heart failure Heart Failure Adapted from Tang et al, Circ Res, 2015 The respiratory system must be protected from pathogens Filtering action of cilia that line airways Mechanisms: Cilia move mucus to pharynx Dust particle Mucus layer traps inhaled particles. Watery saline layer allows cilia to 1. Filtering action of the nose push mucus toward pharynx. Cilia 2. Mucous and action of cilia lining the airways Goblet cell 3. Antibodies secreted into respiratory surfaces secretes mucus. Nucleus of 4. Macrophages in respiratory tract and alveoli columnar epithelial cell Basement membrane Ciliated epithelium of the trachea Immune cells secrete antibodies disable pathogens ~Figure 17.5 Measuring lung function - Spirometry How is lung function measured? Spirometry Fig. 17.7 Measuring lung function - Spirometry Lung volumes and capacities VT: tidal volume IC: Inspiratory capacity IRV: Inspiratory reserve volume FRC: Functional residual capacity ERV: Expiratory reserve volume VC: Vital capacity RV: Residual volume TLC: Total lung capacity Based on Fig 17.7b Obstructive and Restrictive lung diseases Obstructive lung disease (Obstr.): asthma – more airway resistance Inspiratory restrictive lung disease (Insp. restr.): pulmonary fibrosis – less compliant lung Expiratory restrictive lung disease (Expir. restr.): obesity – organs push diaphragm upward Effros, GI Motility online, 2006 Forced expiratory volume and vital capacity Following maximal inhalation: Forced expiratory volume (FEV) = volume of air forcefully exhaled in 1st second Forced vital capacity (FVC) = volume of air forcefully exhaled time FEV and FVC in Obstructive lung disease (e.g., Asthma) Very Low FEV: Problem with air escaping lungs, especially at high velocities Low FVC: Problem with air escaping at all points. Improved with bronchodilators Pierce et al, Respirology, 2005 FEV and FVC in Restrictive lung disease (e.g., Fibrosis) Low FEV: Lung damage Low FVC: Low compliance Pierce et al, Respirology, 2005 Need help with this material? 1. Refer to the Silverthorn textbook 2. Post questions on the discussion board 3. Attend help session with prepared questions 4. Email me at [email protected]