Lecture 23: Organization of the respiratory system

Question 1

Describe what the respiratory system looks like (number of lung lobes, breakdown of bronchi)

Answer 1

right lung has 3 lobes, left lung has 2 lobes. Bronchi broken down into conducting airways (bronchi with no alveoli) and respiratory airways (bronchi with alveoli). terminal bronchiole is the smallest bronchiole without alveoli. 32 branches.

Question 2

What are the 9 functions of the respiratory system?

Answer 2

1) Gas exchange (O2 and CO2)
2) Condition inspired air (warm, moisten, filter)
3) Secrete mucus (trap foreign particles)
4) Filter small emboli from the blood (small blood clots and air bubbles)
5) secrete surfactant and ACE
6) pH balance
7) olfaction
8) vocalization at the larynx
9) heat loss

Question 3

Describe the two different types of dead space

Answer 3

anatomical dead space - air in bronchi of conducting airways
alveolar dead space - air in alveoli that aren’t perfused
physiological dead space - combo of the two

Question 4

Describe the respiratory epithelium in the large conducting airways, and how it changes as the bronchi branch

Answer 4

has sol layer secreted by columnar epithelia to allow cilia to move freely
goblet cell secretes mucin and sialic acid to make mucus
submucosal gland secretes water, ions, mucus, bacteriocidal agents
mucus layer - traps airborne particles

as the bronchi branch, there is fewer goblet cells, no submucosal glands. radius decreases until there is only one layer of epithelial cells

Question 5

What are the 3 types of alveolar pneumocytes

Answer 5

type 1 (95%): function for gas exchange, fused to the endothelium (capillaries)
type 2: synthesize surfactant, regeneration of type 1 cells
type 3: microvilli brush cells - possible chemoreceptors

Question 6

What are the Pores of Kohn and Canals of Lambert?

Answer 6

channels between alveoli, help if alveoli are blocked or congested, prevents alveolar collapse due to surface tension

Question 7

What are the 2 sources of pulmonary blood supply? How is pulmonary circulation different from systemic circulation?

Answer 7

1) pulmonary arteries: de-O2 blood from the right ventricle, goes through very thin capillaries slowly (1 RBC at a time) and then goes to pulmonary veins
2) bronchial arteries: O2 blood from the left ventricle perfuses the large conducting airways, some (1/3) drains to bronchial arteries that go to right atrium, 2/3 drains to pulmonary vein, this de-O2 blood mixes with the O2 blood sent to the rest of the heart

pulmonary circulation has thinner and larger diameter arteries, therefore more compliance. reduces pulse pressure, stores large volume of blood, much lower pressures