Airways

Question 1

Characteristics of Alveolar epithelial type I cells?

Answer 1

Thin,

cover 95% of surface

Question 2

Characteristics of Alveolar epithelial type II cells?

Answer 2

Greater number than type I but smaller, covers 5%

Question 3

How are the airways adapted for their role?

Answer 3

Mechanical stability made of cartilage

Control of calibre - by smooth muscle

Protection and cleansing method to remove particles

Question 4

What is the conchae?

Answer 4

highly vascular – contribute to warming and ‘humidification’ of intra-nasally-inhaled air
Nasal hairs filter out large particles

Question 5

Describe the organization of airway structures?

Answer 5

• transverse section image

Question 6

How are the following cells described :

Goblet (epithelium), mucous, serous (glands)

Answer 6

Secretory cells

Question 7

How can the following cells be described?

Ciliated, Intermediate, Brush, Basal?

Answer 7

Lining cells

Question 8

…

Answer 8

….

Question 9

….

Answer 9

….

Question 10

What are Mucin granules?

Answer 10

Found in goblet cells, released from mucous acini as highly condensed mucin which when released becomes decondensed and expands as mucous.

Question 11

What do serous cells secrete?

Answer 11

Anti-bacterial enzymes : lysozyme

Question 12

What are found in the bronchial gland?

Answer 12

Serous acini

Mucous acini

Question 13

What allows the cilia to move?

Answer 13

Microtubules called Axoneme. 9 + 2 structure

Metachronal rhythm

• check apical hooks and anchoring proteins on diagram

Question 14

What is the function of airway epithelial ( secretory )

Answer 14

Secretion of mucins, water and electrolytes

components of ‘mucus’ (+ plasma, mediators etc

Question 15

What inflammatory mediators does the epithelium regulate and produce?

Answer 15

• Nitric oxide (NO - via nitric oxide synthase, NOS) to control ciliary beat
• 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

Question 16

What are the three functions of the smooth muscle of the airway?

Answer 16

Structure of airways

Tone: airway caliber by contraction and relaxation

Secretion: mediators, cytokines, chemokines

Question 17

What changes occur in smooth muscle during inflammation e.g. asthma?

Answer 17

Structure of airways: hypertrophy and proliferation

The secreting cells release more quantities e.g. NO, Prostaglands, Cytokines, chemokines, adhesion molecules = inflammatory cell recruitment

Question 18

Blood returns from tracheal circulation via ( a )

Blood returns from bronchial circulation to both sides of the heart via ( b )

Answer 18

a - systemic veins

b - bronchial and pulmonary veins

Question 19

What functions of the tracheo-bronchial circulation does the blood supply help? ( 7 )

Answer 19

• gas exchange
• warms air
• humidification
• clears inflammatory mediators
• clears inhaled drugs
• supplies inflammatory cells
• supplies proteinnaceous plasma

Question 20

What mediators control airway functions? 4

Answer 20

histamine
arachidonic acid metabolites (e.g. prostaglandins, leukotrienes)
cytokines
chemokines

Question 21

What is the motor pathway to the smooth muscles of the lung

Answer 21

Cholinergic parasympathetic pathway.

relaxes airway

Question 22

What does adrenaline do to the airways?

Answer 22

Relaxes smooth muscle to open up airways

• in addition to NO

Question 23

What unique pathway do humans have to relax smooth muscle?

Answer 23

Nerves releasing NO for Nitric oxide synthase

Nerves from the Cervical
thoracic ganglion.

Question 24

Regulatory inflammatory cells in airways?

Answer 24

Check slide 36 of ppt

They make various mediators which do various things

Question 25

Give three examples of respiratory disease with loss of airway control and inflammation leading to obstruction

Answer 25

Asthma
COPD
Cystic fibrosis

• involves airway remodelling