Chapter 1: Structure and Function Flashcards
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List 4 functions of the lungs
- gas exchange
- metabolizes compounds
- filters material
- blood reservoir
Describe Fick’s Law of diffusion
Fick’s law describes that the amount of gas movement through a barrier is proportional to its surface area and gas concentration gradient, and inversly proportional to it’s thickness
D –> Diffusion constant
List the conducting airways from the trachea downwards
trachea - main bronchi - lobar bronchi - segmental bronchi - terminal bronchioles
How does cartilage/smooth muscle proportion change further down the conducting airways?
as airways progress distally –> less cartilage and more smooth muscles
What are the parts of the acinus?
- respiratory bronchioles (some alveoli budding from their walls, some gas exchange)
- alveolar ducts (fully lined with alveoli)
- alveoli/alveolar sacs
How does the velocity of gas flow change throughout the airways?
Proximal - more velocity (smaller radius)
Distal - low velocity (large combined cross-sectional area)
Why does dust usually not reach the acinus?
The velocity of air flow drops so much that the dust will settle at the terminal bronchioles
Name the structures
C: capillary/plasma
Ec: RBC
IN: interstitium
EP: epithelium
EN: endothelium
BM: basement membrane
FB: fibroblast
Arrow: gas diffusion pathway
What do you call the connection between the alveoli?
Pores of Kohn
What is part of the bronchovascular bundle? How does it run?
- arteries and bronchi travel together down the center of the lobules
- initially veins run together with bronchi and arteries, but towards the periphery they move away to pass between the lobules
How wide are the pulmonary capillaries?
7-10 micrometer (just large enough for RBCs to pass through)
How thick is the blood gas interface?
0.2-0.3 micrometer
How much time do RBCs spend in the pulmonary capillary network?
0.75 seconds (probably pass through 2 or 3 alveoli on the way)
What are the two ways of blood supply for the lungs?
- pulmonary circulation
- bronchial circulation
What part of the lungs does the bronchial circulation supply blood to?
conducting airways - down to the terminal bronchioles
small proportion perfused by bronchial circulation - lung can actually function well without it (e.g., lung transplantation)