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Normal Chest Anatomy
Key Words  chest lungs fx normal chest CT anatomy
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Ashley Davidoff MD  TheCommonVein.net
Keeping the Lungs attached to the Chest Wall via A Two Layered Pleura ? Capillary Forces
The coronally reformatted image of the lung parenchyma has been outlined with the visceral pleura, (pink) the pleural fluid in the pleural space, (orange) and the parietal pleura. (green) Note how at end expiration the parietal pleura in the costophrenic sulcus extends beyond the lung margin so that the visceral pleura is absent in the costophrenic sulcus and there are two layers of parietal pleura facing each other. During inspiration the lung expands into this space.  32634b10
Key Words  lung pleura pulmonary
Ashley Davidoff MD  TheCommonVein.net
Mechanical Forces Bringing Air to Alveoli
Chest Wall,  Diaphragm,  Alveolar Expansion
The five major layers that keep the air moving include the outer bony cage, the muscular layer represented in maroon, the pleural complex (orange yellow orange) the lung (blue) and surfactant within the alveolus. (pink)
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Ashley Davidoff MD  TheCommonVein.net
Chemical Force of Surfactant to Keep the Alveoli Open during Respiration
This a grape like cluster of normal alveoli. 
Key words lung alveolus terminal bronchiole respiratory bronchiole RS normal anatomy drawing 
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Ashley Davidoff MD  TheCommonVein.net
Oxygen Gradients Created by the Lungs Across the Alveolar Membrane
This diagram again shows the alveolus in teal, the arteriolar component of the capillary with red cells in blue and venular component replenished by oxygen in red. As noted above, the PO2 of the arterial blood is 40mmHg while the inspired air is 104mmHg. A pressure gradient thus exists and diffusion from the high to the low pressure occurs with a net movement of oxygen into the blood to equilibrate the pressure. Venous blood is now rich in oxygen with a PO2 of 104mmHg.
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Ashley Davidoff MD  TheCommonVein.net
Fluid Gradients at the Capillary Level
Key Words capillary interstitium arteriole arteriolar pressure capillary pressure venule venular pressure interstitial pressure colloid osmotic pressure plasma colloid osmotic pressure Forces tending to move fluid out of the capillary is capillary pressure of 25mmHg, negative interstitial pressure = 6mmHg and and interstitial osmotic pressure of 5 mmHg = total of 36mmHg Forces holding the holding the fluid in the capillaries include the plasma oncotic pressure of 28mmhg and thus the net outward force is about 8mmHg
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Ashley Davidoff MD TheCommonVein.net