Feb 25 - Respiratory introduction

Feb 25 - Respiratory introduction - Anatomy and Physiology...

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Unformatted text preview: Anatomy and Physiology of the Respiratory System Respiratory s Conducting Airways • Upper airways • Trachea • Bronchial tree s Purposes • • • • warm and humidify air prevent entry of foreign materials passage way to the alveoli Lined with mucociliary blanket Anatomy and Physiology of the Respiratory System Respiratory s Terminal Bronchioles • Anatomic Dead Space s Respiratory Bronchioles • Participate in gas exchange s Alveolar Ducts • Two alveolar ducts branch from each Two respiratory bronchiole respiratory • Surrounded by alveoli Anatomy and Physiology of the Respiratory System Respiratory s Alveoli • Functional unit of the respiratory system, Functional 300 million, large total surface area 300 s Type I Alveolar Cells • gas exchange s Type II Alveolar Cells • Produce, store, and secrete surfactant Anatomy and Physiology of the Respiratory System Respiratory s Surfactant • • • • • lowers surface tension lubricates prevents the collapse of the alveoli stabilizes the alveoli iincreases lung compliance (ability to ncreases stretch) stretch) • eases the work of breathing Anatomy and Physiology of the Respiratory System Respiratory s Deficiency of surfactant • alveolar instability • alveolar collapse (atelectasis) • impairment of gas exchange – preemies Respiratory Breathing Patterns Respiratory Eupnea (normal)- 12-20 breaths/min. s Tachypnea- rapid RR, often shallow s Bradypnea – slow RR s Apnea- absence of breathing s Hyperventilation s Anatomy and Physiology of the Respiratory System Respiratory s Airway Resistance • Pressure which must be overcome to Pressure inflate the lungs inflate s Resistance • • • • nose (greatest) oropharynx larynx conducting airways- bronchioles conducting Anatomy and Physiology of the Respiratory System Respiratory s Expiration • Airways decrease in size • Alveolar ducts decrease in size s Inspiration • Airways increase in size • Alveoli increase in size Gas Transport (part 1) Gas s Ventilation • the exchange of air between the lungs and the the atmosphere the – Pulmonary ventilation Pulmonary • the total exchange of gas – Alveolar ventilation Alveolar • the effective ventilation of the alveoli Gas Transport (part 2) Gas s Perfusion • The flow of blood through the capillaries The surrounding the alveoli surrounding Gas Transport (part 3) Gas s Diffusion • Movement of gas across membrane – difference in pressure – surface area – thickness of alveoli/capillary – type of gas Ventilation/Perfusion Ventilation/Perfusion V = alveolar gas flow (4 L/min) s Q = capillary blood flow (5 L/min) s Ventilation/Perfusion Study Ventilation/Perfusion Main purposes: R/O PE, determine lung Main function function s Normal V/Q Ratio s • 4000 ml air • 5000 ml blood s Normal V/Q 0.8 Ventilation/Perfusion Ventilation/Perfusion s V/Q Mismatch • abnormal distribution of ventilation and abnormal perfusion perfusion • Example: PE= perfusion deficit d/t emboli Example: blocking normal blood flow blocking Ventilation/Perfusion Ventilation/Perfusion s Low V/Q Ratio (< 0.8 - Impaired Low ventilation) ventilation) • iinadequate ventilation of well-perfused nadequate areas of the lung areas s Etiologies of a Low V/Q • • • asthma pulmonary edema pulmonary pneumonia Ventilation/Perfusion Ventilation/Perfusion Very Low V/Q (Blocked ventilation) • blocked ventilation of well-perfused blocked areas of lung areas s Etiologies of a Very Low V/Q • Adult Respiratory Distress Syndrome • Respiratory Distress Syndrome of the Respiratory Newborn Newborn s Ventilation/Perfusion Ventilation/Perfusion s High V/Q Ratio • poor perfusion of well-ventilated portions of poor the lung the s Etiologies of High V/Q Mismatch • Pulmonary embolus- can have V/Q Scan to Pulmonary diagnose diagnose Oxyhemoglobin Dissociation Curve Oxyhemoglobin Oxyhemoglobin Dissociation Curve Oxyhemoglobin PaO2 is the actual amount of O2 PaO2 dissolved in the blood (90-106 mmHg) dissolved s SaO2 is the % of Hb molecules that are SaO2 saturated, or filled, with O2 saturated, s The curve shows the relationship The between PaO2 and SaO2: as PaO2 decreases, SaO2 decreases decreases, s The desaturation of Hb increases as The PaO2 gets around 60 mmHg PaO2 s Oxyhemoglobin Dissociation Curve Curve Remember that Hb’s job is to pickup, Remember transport, and deliver O2 transport, s The “affinity” of Hb for O2 describes The how tight the bond is holding O2 onto the Hb molecules the s There are certain conditions that will There result in a higher or lower affinity of Hb to O2 to s Oxyhemoglobin Dissociation Curve Curve s increased affinity of Hgb for O2 • less oxygen is released to the tissues s Causes for this “left” shift • • • • alkalemia hypocapnia hypothermia decreased levels of 2,3 DPG (enzyme that decreased helps remove O2 from Hgb) helps Oxyhemoglobin Dissociation Curve Curve s s Decreased affinity • More oxygen is released to the tissues This is a compensatory change to meet This the need for more O2 the s Causes for this “right” shift • • • acidemia hypercapnia normal or increased levels of 2,3 DPG Signs and Symptoms of Respiratory Disease Respiratory s s s s s s s Dyspnea Hypoventilation (Hypercapnia) Hyperventilation (Hypocapnia) Cough Hemoptysis Cyanosis Clubbing Signs and Symptoms of Respiratory Disease Respiratory s Pain • • • • angina pleural pain (pleural friction rub) pulmonary pain Costochondritis- MS pain Hypoxemia Hypoxemia s Hypoxemia • Hypoxemia refers to low amounts of O2 in Hypoxemia the blood the s Hypoxemia leads to hypoxia • Hypoxia refers to low amounts of O2 in the Hypoxia tissues tissues • Decreased O2 in the blood means that not Decreased enough O2 is delivered to the tissues enough Hypoxemia - Hypoxia Hypoxemia s Causes • decreased O2 content in inspired air content • hypoventilation due to respiratory hypoventilation suppression (drugs, brain injury) suppression • diffusion abnormalities (pulmonary edema) • Ventilation-perfusion mismatch • Anemia s Pulmonary, cv, and hematologic Pulmonary, systems must all work correctly! systems ...
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This note was uploaded on 02/15/2011 for the course NURS 216 taught by Professor Smith during the Spring '10 term at South Carolina.

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