Structure and Function of the Lung

imissyou419's version from 2017-02-01 23:08


Question Answer
Function of lungMAIN FUNCTION: gas exchange between the blood and external environment by diffusion at blood-gas barrier in alveoli (not exchange of CO2 with O2),
reservoir and filter for blood, involved in metabolism of some compounds and provide airflow for speech
Blood gas valuesdone in systemic arteries to check how much oxygen is in a sample of blood i.e. PaO2(not pulmonary arteries - since that is deoxygenated blood)
Fick's law of diffusion (equation), proportionalityVgas = (constant*(P1-P2))*A/T; rate of gas transport across a tissue sheet is proportional to area of sheet, diffusion constant, difference in partial pressures, inversely proportional to thickness
What type of molecule has large diffusion constant?smaller molecule, more soluble molecule (larger diffusion constant = faster diffusion)
When is diffusion the fastest? (5 properties)smaller molecule, more soluble molecule, larger pressure gradient, larger SA, thin surface
In the lung, what properties of diffusion are there?LARGE SA, THIN SURFACE (properties of blood-gas barrier); pressure gradient (properties of blood flow removing O2 creating imbalance); diffusion constant (property of gas)
Partial pressure of a gaspressure exerted by any one gas in a mixture of gases
Partial pressure equation(fraction of that gas)(total pressure - any counting pressure i.e. water pressure)
Partial pressure of a gas in solutionpartial pressure of the gas that is in equilibrium with the solution (this is regardless of the solubility of the gas in solution i.e. same partial pressure of a gas in water, chocolate milk, guiness)
i.e. partial pressure of O2 in water and blood are both 100 mmHg but there is more oxygen MOLECULES in water than blood b/c of solubility "2L sprint and 1L sprint both half full - 2L will have more molecules"
Blood gas barrier anatomycreated through a repeated branching of airways and alveoli, blood vessels and capillaries essential for gas transport, physical environment of lung is important for its function
What does the air-side of the barrier contain?thin layer of fluid incl. sufactant, lined with very thin type 1 epithelial cell
What does the capillary-side of the barrier contain?lined with endothelial cells
Where is the interstitium?small layer between endothelial and epithelial cells, structural component
How thin is the blood-gas barrier?0.5 um (surfactant, type 1 epithelial, interstitium, endothelial)
What is the surface area of the blood gas barrier of a human lung?50-100 m^2, this large SA is created by repeated branching of airways to create 300 million alveoli and wrapping capillaries around them
What is the structural purpose of airways?structural units contributing the generation of large SA through repeated branching
What is the structural purpose of alveoli?blood gas barrier (gas exchange)
How many generations of airways are there in humans starting at trachea and ending at alveolar sacs? KNOW THIS23
What are the names of the branches? KNOW THIStrachea -> (left and right) bronchus -> bronchiole -> terminal bronchiole -> respiratory bronchiole -> alveolar duct -> alveolar sac
What constitute the conducting zone?Airways, bronchi, bronchioles, terminal bronchioles; devoid of alveoli so do not gas exchange
Respiratory bronchioles have occasional alveoli budding from their walls
Alveolar ductscompletely lined with alveoli
What generations consists of respiratory bronchioles, alveolar ducts, alveolar sacs17-23
What constitute the transitional and respiratory zone?respiratory bronchioles, alveolar ducts, alveolar sacs; have alveoli so can do gas exchange
When does the SA increase the most rapidly?in the respiratory zone (majority of SA is in respiratory zone)
How does pulmonary artery play a part in gas exchange?pulmonary artery branches extensively and forms dense network of capillaries which wrap around alveoli (in the capillaries, blood exposed to largest SA and velocity slowest)
Intrapleural space location, value, what is it created by?space between lung and chest wall (normally -5mmHg = subatmospheric pressure); chest wall has tendency to move outward, lung's elastic properties have tendency to collapse
What is the pressure inside the lung?atmosphereic (intrapulmonary pressure = 0 mmHg)
Pneumothoraxa hole in the diaphgram causing intrapleural pressure to be atmospheric - chest wall will move outwards, lung will collapse

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