BIOL 112 1st Edition Lecture 20 Outline of Last Lecture I Measurement of Blood Volume II Gas Exchange III Respiratory System IV Breathing Ventilation Outline of Current Lecture V Air Processing VI Vocalization VII Oxygen Transport VIII CO2 Exchange Current Lecture I Air Processing Treatment process of air before gas exchange Warming mostly in the nose heat exchange Humidifying related to warming mostly in nasal passages water vapor content from 0 5 to 6 Filtering nose trachea bronchi mucus traps dust and airborne microorganisms ciliated epithelium sweeps mucus constantly toward epiglottis mucus is swallowed and digested in stomach Consequences of air processing failure Tracheostomy patients forced to breathe cold dry air to have a much higher rate of lung infections and inflammations These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Smokers tend to lose epithelial function excess of mucus stimulates the cough reflex smoker s hack Cough Reflex epiglottis and vocal cords snap shut abdominal muscles contract epiglottis relaxes abruptly cough removes materials that epithelia can t handle All gasses exchanged must pass through alveolar cells to enter or exit circulation only exchange surface alveolus is heavily vascularized Respiratory Membrane Surfactant 1 molecule thick prevents alveolar collapse from surface tension ex dipalmitoylphophotidyl choline Extracellular fluid Alveolar Epithelial Cell Intercellular Space Collagen around Capillary Cell Capillary Cell All gasses must be exchanged by simple diffusion NO ACTIVE TRANSPORT of gasses across any surface no facilitated diffusion II Vocalization Noise production vocal cords in larynx cords are thin sheets of muscle stretched between arches of bone and muscles in larynx sound is produced tightening cord muscles and brings them into the air stream cords vibrate perpendicular to direction of airflow pitch and volume varied by varying force and direction of cord movement sound produced is modulated by other parts of respiratory system III Oxygen Transport Hemoglobin protein that carries oxygen in blood a tetramer 4 polypeptides can carry 4 oxygen molecules Hemoglobin can carry much more oxygen per volume of blood than by mere solution of oxygen in plasma Carried in erythrocytes because it is easier to maintain high concentrations of mercury in suspension inside cells than by solution in plasma Oxygen Affinity Curve S shaped curve the more O2 binds the higher the affinity for binding more up to saturation IV CO2 Exchange Unlike O2 CO2 is highly soluble and reacts with water Rapid diffusion rate of CO2 permits quick removal from blood into alveolar air In tissues most CO2 is in the form of HCO3 In lungs CO2 is released as gas
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