Structure and function of the airway*

Question 1

What shape is the cartilage in the trachea?

Answer 1

C shape, doesnt go all the way round

Question 2

Why is there no cartilage at the back of the trachea?

Answer 2

So food can go down the oesophagus which is attached to the back of the trachea

Question 3

What is the branching in the airways called?

Answer 3

Dichotomous branching- 2 to 2 to 2 (doubles)

Question 4

What type of stability does cartilage provide?

Answer 4

Mechanical stability

Question 5

Where does gas exchange occur?

Answer 5

Alveolar region

Question 6

How many macrophages are there in an alveolus?

Answer 6

2 or 3

Question 7

What do fibroblasts in the alveolar unit produce?

Answer 7

The matrix that the alveoli are contained

Question 8

Why are type 1 cells good for providing the barrier for gas exchange?

Answer 8

They are very thin- short diffusion distance

Question 9

What do type 2 cells do?

Answer 9

Replicate the produce type one cells
Secrete surfactant

Question 10

What percentage do type 1 and type 2 cells cover alveolar surface?

Answer 10

Type 1- 95%
Type 2- 5%

Question 11

What shape are type 1 cells?

Answer 11

Fried egg shape

Question 12

What does the calibre of the airway mean?

Answer 12

How open or closed it is

Question 13

What controls the calibre of the airway

Answer 13

Smooth muscle

Question 14

What are the conchae?

Answer 14

Shelves of bone in the nasal pathway

Question 15

Why do the conchae need to be highly vascular?

Answer 15

To contribute to warming and humidification of air so it doesn’t damage the delicate thin type one cells

Question 16

Why are nasal hairs in the conchae important?

Answer 16

To filter out large particles

Question 17

What is the pharynx?

Answer 17

A common passageway for liquids, food, and air

Question 18

What is the structure of a cross section of the airway wall (innermost to outermost layer)?

Answer 18

airway lumen, mucus, cillia, epithelial lining and goblet cells, submucosal glands smooth muscle and blood vessels, cartilidge

Question 19

What is mucociliary transport?

Answer 19

Mucus traps particles and cilia waft that mucus to the back of the throat

Question 20

Why are there a lot of mitochondria around cilia?

Answer 20

Because a lot of mitochondria is required for them to beat all the time

Question 21

What are the 2 types of acini in airway submucosal glands?

Answer 21

Mucus acini and serous acini

Question 22

What do serous cells secrete?

Answer 22

Antibacterial enzymes

Question 23

Describe the transverse section of a cilia.

Answer 23

9 pairs of things in a circle with two in the middle

Question 24

What are the 4 functions of airway epithelium?

Answer 24

1. Secretion of mucins, water and electrolytes
2. Movement of mucus by cilia – mucociliary clearance
3. Physical barrier
4. Production of regulatory and inflammatory mediators

Question 25

Name 6 regulatory and inflammatory mediators produced by the airway epithelium

Answer 25

Nitric oxide (NO - via nitric oxide synthase, NOS)
Carbon monoxide (CO - via hemeoxygenase, HO)
Arachidonic acid metabolites (e.g. prostaglandins – via COX)
Chemokines (e.g. interleukin (IL)-8)
Cytokines (e.g. GM-CSF)
Proteases