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Case 3 Part 1 PRECLINEAZY Shayna WaliaT opics Covered Lung Anatomy & Histology Respiratory Physiology Ventilation and Perfusion Mechanics of BreathingLUNG ANATOMY & HISTOLOGYRespiratory Tree Trachea Bronchi – primary, secondary, tertiary Bronchioles – conducting, terminal then respiratory - conducting zone ends at terminal bronchioles (16th gen) - respiratory zone (start of acinus) begins at respiratory bronchioles Alveolar ducts Alveolar sacs (23rd gen)Respiratory Tree Trachea Bronchi – primary, secondary, tertiary Sternal Angle Rib, 2nd T4 / T5 Aortic arch Tracheal bifuraction (carina) Pulmonary trunk bifurcation Left recurrent laryngeal nerve Azygos vein Nerves of cardiac plexus Thoracic ductRespiratory Tree Trachea Bronchi - R main bronchus is shorter and wider than L main bronchus – foreign bodies are more likely to be aspirated into the R side Right Bronchus SuperiorRespiratory Tree - conducting zone ends at terminal bronchioles (16th gen) - warming, humidifying and filtering air - obstructive lung disease - respiratory zone begins at respiratory bronchioles - gaseous exchange - restrictive lung disease20 incomplete rings of tracheal cartilage adapted to warm and moisten the air – prevents collapse during expiration Club cells - present in bronchioles, responsible for immune defense, repair and detoxification COPDhttps://histologyguide.org/slidebox/slidebox.htmlhttps://histologyguide.org/slidebox/slidebox.html bronchial / hyaline tracheal cartilage pseudostratified columnar epithelium basement membrane - thick eosinophilic band which contains mast cells and macrophages lamina propria - vascularised and trafficked by WBCs, thickened in disease smooth muscle Question 1 A 1 A man presents to the A&E with acute onset breathlessness and hyperventilation after a B 2 motor-cycle accident. He sent for an urgent CXR. The results show a tension pneumothorax in his C 3 right lung. The patient is treated however needs a 4 lung transplant. How many fissures does the D right lung have? Question 1 A 1 A man presents to the A&E with acute onset breathlessness and hyperventilation after a B 2 motor-cycle accident. He sent for an urgent CXR. The results show a tension pneumothorax in his C 3 right lung. The patient is treated however needs a lung transplant. How many fissures does the D 4 right lung have? R lung – 2 fissures, 3 lobes! Question 2 A L lower lobe A 72-year-old man comes a history of coughing up blood in the morning and progressive shortness of breath for the past 5 months. He has lost over 14 lbs of weight in the past 5 B Brachial plexus months and complains of significant loss of appetite. Physical examination shows conjunctival pallor. He has a 30 pack year history of smoking. A chest x-ray shows a mediastinal mass C Sympathetic chain and ipsilateral elevation of the right diaphragm. Compression of which of the following structures by the L recurrent laryngeal nerve mediastinal mass best explains the chest x-ray findings? D E Phrenic nerve Question 2 A L lower lobe A 72-year-old man comes a history of coughing up blood in the morning and progressive shortness of breath for the past 5 months. He has lost over 14 lbs of weight in the past 5 B Brachial plexus months and complains of significant loss of appetite. Physical examination shows conjunctival pallor. He has a 30 pack year history of smoking. A chest x-ray shows a mediastinal mass C Sympathetic chain and ipsilateral elevation of the right diaphragm. Compression of which of the following structures by the L recurrent laryngeal nerve mediastinal mass best explains the chest x-ray findings? D E Phrenic nerveLUNG PHYSIOLOGY BLOOD BRAIN BARRIER CAPILLARY BLOOD CSF CHEMORECEPTOR FIRING AND VENTILATION CHEMORECEPTORS H2O + CO2 HCO3 + H+ H2CO3 H2CO3 HCO3 + H+ H2O + CO2Other Receptors of the Lungs BRONCHOCONSTRICTION BRONCHODILATION Control of Breathing Central chemoreceptors - located near the ventrolateral medullary surface - relatively slow response time - relative insensitivity to PO2 - long term response - sensitive to pH of CSF Peripheral Chemoreceptors - located in aortic and carotid bodies - decreased PO2, increased PCO2 and increased H+ causes increased firing - responds rapidlyMECHANICS OF BREATHING MECHANICS OF BREA THING “BUCKET - HANDLE MOVEMENT” INSPIRATION EXPIRATION - atmospheric p.a > alveolar p.a - atmospheric p.a < alveolar p.a - diaphragm and external intercostals contract - diaphragm and external intercostals relax - chest wall expands - chest wall recoils inward - intrapleural p.a. reaches -4mmHg - intrapleural p.a. reaches subatmospheric p.a - lungs expand, decreasing intrathoracic p.a - lungs recoil, increasing intrathoracic p.a - alveolar pressure decreases - alveolar pressure increasesMuscles involved - diaphragm - external intercostal muscles Accessory muscles of inspiration - sternocleidomastoid - scalene - pectoralis minor Accessory muscles of expiration - internal intercostals - abdominal muscles (rectus, internal and external oblique, transversus) Question 3 A Peripheral chemoreceptors are found in the carotid arteries and arch of the aorta Which statement is false with Irritant receptors cause bronchospasm respect to the control of B ventilation? Respiratory centers control rate and C depth of respiration D Involuntary control of respiration is from the medulla and pons Central chemoreceptors respond E to changes in O2 Question 3 A Peripheral chemoreceptors are found in the carotid arteries and arch of the aorta Which statement is false with Irritant receptors cause bronchospasm respect to the control of B ventilation? Respiratory centers control rate and C depth of respiration D Involuntary control of respiration is from the medulla and pons Central chemoreceptors respond E to changes in O2COMPLIANCE P/V LOOP BOYLE’S LAW! Compliance - distensibility of the lung (volume over pressure) - l/cm2 Elasticity - ability of lung to retain it’s original structure after being stretched ⇒ inverse relationshipVENTILATION:PERFUSION RA TIOVentilation - flow of air in and out of alveoli Perfusion - flow of blood to alveolar PA > Pa > PV ZONE 1 capillaries Pa > PA > PV ZONE 2 V and Q are better at the base of lungs Pa > PV > PA ZONE 3 HYPOXIC PULMONARY VASOCONSTRICTIONV:Q ⇒ ∞ - alveolar dead space - PE can cause increase in physiological dead space (anatomical + alveolar dead space) PA > Pa > PV ZONE 1 V:Q = 0 Pa > PA > PV ZONE 2 - blood passing through lung Pa > PV > PA ZONE 3 without contacting alveolar air - physiological shunt - pathophysiological shunt (fluid filled alveoli) Question 4 Emphysema A Which of the following will cause Pulmonary FIbrosis an increase in compliance of the B lung? Pectus Excavatum C D Loss of surfactants E Pneumothorax Question 4 Emphysema A Which of the following will cause Pulmonary FIbrosis an increase in compliance of the B lung? Pectus Excavatum C D Loss of surfactants E Pneumothorax Question 5 Diaphragm and internal intercostals A Which of the following are the Internal and external intercostals main muscles involved in B inspiration? Diaphragm C D Scalene muscle and diaphragm E Diaphragm and external intercostals Question 5 Diaphragm and internal intercostals A Which of the following are the Internal and external intercostals main muscles involved in B inspiration? Diaphragm C D Scalene muscle and diaphragm E Diaphragm and external intercostals REFERENCES • https://www.medmastery.com/guides/blood-gas-analysis-clinical-guide/what-ventilation-perfu sion-ratio • https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRJ_8YLmYS_ZMS1VDFA3gwNthlYH3u 2GgYZ_w&s • https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTukEQ7YuQgxHDe599IvtG3bgErLeHn nVLYoA&s • https://i0.wp.com/thoracickey.com/wp-content/uploads/2019/10/f01-02-9780323595780.jpg ?w=960 • https://o.quizlet.com/6rPXpDJVslYksJpJd83e9w.jpgPLEASE FILL OUT THE FEEDBACK FORM PLEASE TUNE IN TO OUR REMAINING SESSIONS THIS WEEK osceazyofficial OSCEazy osceazy@gmail.com OSCEazy osceazyofficial