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Lungs By the end of the lesson you should be able to: Label the internal structures of the lungs State the features of the alveoli which allow efficient gas exchange Explain the role of diffusion in gas exchange State the features of the capillary network that allow efficient gas exchange Breathing Passive (muscles relax) Active (muscles contract) Intercostal muscles move ribs down & in Intercostal muscles move ribs out & up Volume decreases Volume increases Pressure increases Pressure decreases Air pushed out Air drawn in The upper respiratory tract: Where it all begins! Air enters, but must be warmed, moistened & filtered: Nasal Cavity - Turbinate bones, mucosa - Capillaries: warm, moisten - Nasal hairs & mucus filter Pharynx links nasal & oral cavities Epiglottis protects trachea when swallowing food The lungs organs that allow gas exchange oxygen in / CO2 out trachea - has rings of cartilage bronchi (bronchus) bronchioles alveoli (alveolus) Protecting the lungs Very delicate organs! Several structures: Inside the Trachea: - Mucus traps microbes - Cilia sweep up mucus Rib Cage: defines our Thoracic Cavity; paired bones with intercostal muscles, internal & external Pleural membrane Diaphragm Alveoli (air sacs) provide large surface area for gas exchange one lung equivalent to a tennis court of surface area using alveoli footprints alveoli oxygenated blood air in air out air sac in lungs skool gas exchange deoxygenated blood body cells Features of Alveoli for efficient gas exchange large surface area to diffuse oxygen. moist surface to allow oxygen to dissolve. thin lining to allow easy diffusion of gases. dense network of capillaries for easy gas exchange. skool adaptation of alveoli Features of capillaries for efficient gas exchange Vast network to carry CO2 and O2 Large surface area to transport gases Very delicate! Walls are one cell thick so gases can pass through quickly and easily. Common Lung Problems You probably know some of these: Asthma: bronchiole muscles contract, spasm; limits air flow Bronchitis: irritation of bronchi; painful! Pneumonia: many forms – bacterial, viral & others; fluid accumulation in lungs limits gas exchange Cystic Fibrosis: cilia fail to move mucus, which clogs alveoli gradually; less oxygen enters blood.