Chapter 1: Structure and Function

Question 1

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List 4 functions of the lungs

Answer 1

• gas exchange
• metabolizes compounds
• filters material
• blood reservoir

Question 2

Describe Fick’s Law

Answer 2

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

Question 3

List the conducting airways from the trachea downwards

Answer 3

trachea - main bronchi - lobar bronchi - segmental bronchi - terminal bronchi

Question 4

How does cartilage/smooth muscle proportion change further down the conducting airways?

Answer 4

as airways progress distally –> less cartilage and more smooth muscles

Question 5

What are the parts of the acinus?

Answer 5

• respiratory bronchioles (some alveoli budding from their walls, some gas exchange)
• alveolar ducts (fully lined with alveoli)
• alveoli/alveolar sacs

Question 6

How does the velocity of gas flow change throughout the airways?

Answer 6

Proximal - more velocity (smaller radius)
Distal - low velocity (large combined cross-sectional area)

Question 7

Why does dust usually not reach the acinus?

Answer 7

The velocity of air flow drops so much that the dust will settle at the terminal bronchioles

Question 8

Name the structures

Answer 8

C: capillary/plasma
Ec: RBC
IN: interstitium
EP: epithelium
EN: endothelium
BM: basement membrane
FB: fibroblast
Arrow: gas diffusion pathway

Question 9

What do you call the connection between the alveoli?

Answer 9

Pores of Kohn

Question 10

What is part of the bronchovascular bundle? How does it run?

Answer 10

• 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

Question 11

How wide are the pulmonary capillaries?

Answer 11

7-10 micrometer (just large enough for RBCs to pass through)

Question 12

How thick is the blood gas interface?

Answer 12

0.2-0.3 micrometer

Question 13

How much time do RBCs spend in the pulmonary capillary network?

Answer 13

0.75 seconds (probably pass through 2 or 3 alveoli on the way)

Question 14

What are the two ways of blood supply for the lungs?

Answer 14

• pulmonary circulation
• bronchial circulation

Question 15

What part of the lungs does the bronchial circulation supply blood to?

Answer 15

conducting airways - down to the terminal bronchioles

small proportion perfused by bronchial circulation - lung can actually function well without it (e.g., lung transplantation)

Question 16

Explain how the conducting airways protect from inhaled particles

Answer 16

• large particles filtered out in the nose
• smaller particles depositing in the conducting airways –> taken up by mocous (produced by mucous glands higher up and goblet cells in the bronchial walls) –> transported up via the cilia staircase to the epiglottis –> swallowed

Question 17

Explain how the acinus section of the lungs protects itself from inhaled foreign particles

Answer 17

alveoli have no cilia
particles are enguled by macrophages –> particles removed via the lymphatics or blood flow

particles removed by blood flow will be trapped by tiny blood vessels and released into the venous circulation to prevent the from reaching the left/systemic circulation

Question 18

What type of compound is surfactant and which cells produce it?

Answer 18

• a phospholipoprotein
• Type II pneumocytes

Question 19

What part of the lungs are supplied by the bronchial arteries?

Answer 19

bronchial arteries supply the lungs down to about the terminal bronchioles