Lung Disease

Question 1

What is the structure of the lungs?

Answer 1

• Pipe = trachea
• Bronchi = branched bit off trachea
• Bronchioles = branches inside the lung
• Alveoli = At the end of Bronchioles

Question 2

How is the respiratory system divided?

Answer 2

Divided into 2 zones which vary in respect to function and structure
- Conducting zone- start of respiratory system
- Respiratory zone- located deeper in lungs

Question 3

What are the roles of the conducting zone?

Answer 3

Passageway for air into and out of lungs
‘series of tubes’
Leads inspired air to the gas exchange regions
Not directly involved in gas exchange

Question 4

What other roles does the conducting zone have?

Answer 4

• Filters, warms and moistens air
• Defence- mucociliary escalator- traps and removes potential pathogens

Question 5

What do the walls of airways contain in the CZ?

Answer 5

The walls of airways in the larger airways of the CZ contain smooth muscle

Question 6

What does the smooth muscle in the CZ control?

Answer 6

Lumen size of airway
Dilation of airways
Constriction of airways

Question 7

What is the main function of the respiratory zone?

Answer 7

Gas exchange (oxygen diffuses out of the lungs into the blood)

Question 8

Where does the respiratory zone begin?

Answer 8

The respiratory zone begins where the terminal bronchioles join a respiratory bronchiole
Air passes from the smallest airways (tubes) to alveoli
Respiratory bronchioles, alveolar ducts and alveoli

Question 9

What do conducting airways consist of?

Answer 9

Of a series of (hollow) branching tubes
Tubes become progressively narrower, shorter and more numerous the deeper in the lung they are located
Continuous passageway for air to move into and out of lungs

Question 10

What is the structure of the lungs?

Answer 10

Trachea branches into 2 bronchi (one leads to each lung)
Bronchi divide into 2 smaller bronchi, which continue to divide
In total there are 23 generations of airways
From trachea to alveolar sacs

Question 11

What is the bronchial tree consisted of?

Answer 11

Conducting zone = airway generations 0-16
16th airway generation is the terminal bronchioles
17th generation: respiratory bronchioles
Start of respiratory zone
Last 7 airway generations (17-23) are respiratory zone

Question 12

Where does the respiratory zone begin?

Answer 12

Begins where terminal bronchioles branch to form a respiratory bronchiole
These then branch to form alveolar ducts
Connect the respiratory bronchioles to a cluster of alveoli

Question 13

What do alveolar ducts supply?

Answer 13

They supply an alveolar sac
Each duct delivers air to several alveoli
Grape-like structures
Alveoli are the last (23rd) airway generation
Gas exchange
Wrapped in blood vessels

Question 14

What are the different cells present in the lung?

Answer 14

• Ciliated cells
• Basal cells
• Intermediate cells
• Clara cell
• Goblet cells (discharge mucus)
• Alveolar macrophage
• Alveolar epithelial cells

Question 15

How does the structure of the airways change in the lungs?

Answer 15

Changes as you get deeper in the lungs
Single layer of epithelial cells is a common feature

Question 16

How are the lung airways lined?

Answer 16

Airways are lined by a continuous, single layer of epithelial cells
Structure and function of epithelial cells changes along the respiratory tree

Question 17

What are the layers of cells in the conducting airways?

Answer 17

• Mucus
• Ciliated epithelial cells
• Goblet cells
• Basement membrane
• Smooth muscle
• Nerve Innervation
• Cartilage

Question 18

What are the functions of epithelial cells in the conducting airways?

Answer 18

Physical barrier
Muco-ciliary clearance
Metabolism of inhaled agents
Detoxification
Attraction and activation of immune cells
Regulation of airway smooth muscle function

Question 19

What do the cell types in the conducting airway epithelium do?

Answer 19

Ciliated epithelial cells- physical barrier and transport of mucus from lung
Goblet cells- Mucus secretion
Basal cells- Progenitor for ciliated and goblet cells
Clara cells- Production of surfactant
Basement membrane- Extracellular matrix underneath epithelium cells

Question 20

What other cell types exist in the conducting airway?

Answer 20

Resident immune cells are found underlying the airway epithelium and can be activated by various stimuli
APC’s

Question 21

What does the respiratory zone consist of?

Answer 21

Alveolar epithelium- single layer of epithelial cells

Question 22

What 2 cell types is alveolar epithelium formed from?

Answer 22

Type 1 Epithelial cells (gas exchange)
Type 2 Epithelial cells (synthesis and secretion of surfactant and progenitors for type 1 cells)

Question 23

What type of cells are found in alveoli?

Answer 23

Alveolar macrophages are found in alveoli
Recognition and clearance of pathogens