Structure and function of airways

Question 1

Describe the structure and function of type 1 alveolar cells.

Answer 1

Squamous and very thin and facilitate gas exchange.

Question 2

Describe the structure and function of type 2 alveolar cells.

Answer 2

Granular and cuboidal. Replicate to replace type 1 alveolar cells. Secrete pulmonary surfactant. Secrete antiproteases. Have a role in xenobiotic metabolism.

Question 3

What makes up most of alveolar surface by surface area?

Answer 3

Type 1 alveolar cells.

Question 4

What makes up most of alveolar surface by cell count?

Answer 4

Type 2 alveolar cells.

Question 5

What does pulmonary surfacant do?

Answer 5

Reduces surface tension prevents alveolar from collapsing.

Question 6

What other cells can you find in the alveolar region?

Answer 6

Macrophages and fibroblasts.

Question 7

What is the function of the airway?

Answer 7

O2 to alveoli and CO2 out of lungs.

Question 8

What are the structural components that make up the airway and can you explain the function of these components?

Answer 8

Cartillage is for mechanical stability.Smooth muscle to control airways (constriction and dilation).

Question 9

How is the nose adapted for breathing?

Answer 9

Conchae in the nose are highly vascular. This warms and humidifies nasally inhaled air. Nasal hairs filter out large particles.

Question 10

What produces mucus in the airways?

Answer 10

Goblet cells and submucosal glands.

Question 11

How are cilliated cells adapted?

Answer 11

Contain lots of mitochondria.

Question 12

Two kinds of cells in the submucosal gland? What are their functions?

Answer 12

Mucous and serous cells. Mucuous cells secrete mucus. Serous cells secrete anti bacterial enzymes.

Question 13

Apart from mucus what else is released from the submucosal gland?

Answer 13

Antibacterial enzymes, water and salts.

Question 14

Describe ciliary structure?

Answer 14

Axoneme that has a 9 + 2 microtubule arrangement.

Question 15

What is the movement of mucus by cilia called? What is the function?

Answer 15

Mucociliary clearance. Physical barrier to infectious agents.

Question 16

Regulatory and inflammatory mediators you would find in the airways?

Answer 16

Nitric oxide, carbon monoxide and arachidonic acid metabolites.

Question 17

What does inflammation of airway smooth muscle cell result in?

Answer 17

Hypertrophy and proliferation of smooth muscle. Contraction and relaxation of smooth muscle. Cytokine and chemokine secretion. Nitric oxide and prostaglandin release.

Question 18

Describe and explain airway vascalature?

Answer 18

Requires high amounts blood flow. To warm inspired air, clear inflammatory mediators and clear inhaled drugs.

Question 19

What nerves controls airway function?

Answer 19

Parasympathetic and sensory nerves.

Question 20

What regulatory and inflammatory mediators can control airway function?

Answer 20

Histamines, Arachinodic acid metabolites, cytokines and chemokines.

Question 21

What other molecules can control airway function?

Answer 21

Proteases (e.g neutrophil elastase) and reactive oxygen species.

Question 22

Explain airway constriction by nerves

Answer 22

Solid enters airway and detected by sensory receptors. Excitation of sensory nerves up to brain stem, Excitation of parasympathetic nerves cause release of ACh from preganglionic terminal ends. This results in release of ACh from post ganglionic fibres. ACh cause contraction of smooth muscle in airways and mucus secretion.

Question 23

What cause airway relaxation.

Answer 23

Release of adrenaline from adrenal gland and release of nitric oxide from nerves from spinal cord.