BIOLOGY 151 1st Edition Lecture 34 Outline of Last Lecture 1. Circulatory system2. CirculationOutline of Current Lecture 1. Respiration: The Lung2. Control of breathingCurrent Lecture - 4/15Respiration: The Lung:- job of the lung is to provide a very large surface area over which oxygen and carbon dioxide can be exchanged with the blood- nose, pharynx, larynx, trachea, bronchus, bronchioles, alveolus, and reverses way out- each alveolus surrounded by a capillary bed, and gas exchange occurs here- thin walls mean that diffusion distance is small and that increases efficiency of transfer- no gas exchange in airways, only deliver air- airways sweep out excess materials- job of ciliated cells is to transport stream of mucus outwards- major difference from circulatory system is that lungs do not move air- diaphragm separates thoracic and abdominal cavities- change in volume of thoracic cavity = change in lung volume- volume in lungs decreases when diaphragm pushes up- diaphragm forms bottom of thoracic cavity and separates it from the abdominal cavity - whole thoracic cavity lined with epithelium called pleura- lungs are pushed into it- chest cavity and lungs mechanically linked through pleura- muscles between adjacent ribs contract and make ribs swing upward, expanding chest cavity- at the same time, diaphragm muscles contract and lower floor of chest cavity, making volume increase even more- emphysema causes damage to alveoli, which decreases the elasticity of the lungsControl of breathing:- contraction of muscles and diaphragm in response to bursts of nerve impulses - respond to pH changes in blood due to changes in carbon dioxide or lactic acidThese 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.- when oxygen level is very low, there are oxygen sensors in the aorta and carotid arteries that respond and increase rate of
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