Respiratory Histopathology

Question 1

What is the conducting system of the respiratory system?

Answer 1

• airways starting at nasal cavity - ends at terminal bronchioles

Question 2

What is the respiratory zone of the respiratory system?

Answer 2

• starts at respiratory bronchioles - ends at the alveoli sacs

Question 3

What are the 3 main functions of the conducting system that they must ensure happens to air in the respiratory system?

Answer 3

• clean air - warm air - protect airways

Question 4

What cells lines the conducting system of the respiratory system?

Answer 4

• pseudostratified ciliated columnar epithelial cells

Question 5

Pseudostratified ciliated columnar epithelial cells line the membranes of the conducting system of the respiratory system, but what fills the rest of the airways?

Answer 5

• lamina propria - made of loose connective tissue

Question 6

Pseudostratified ciliated columnar epithelial cells line the membranes supported by loose connective tissue called the lamina propria in the conducting system of the respiratory system, but what are the other 3 main aspects found within the lamina propria?

Answer 6

• blood vessels
• mucous glands
• serous glands

Question 7

What do serous glands secrete in conducting system of the respiratory system?

Answer 7

• proteins in a less viscous solution than mucous glands

Question 8

What is the muscociliary escalator?

Answer 8

• interplay between mucous and ciliary in airways - remove debris, pathogens etc… - can be damaged in lung disease

Question 9

Where is the Olfactory Epithelium located?

Answer 9

• in the roof of the nasal cavity
• olfactory = means smell

Question 10

Sustentacular cells line the Olfactory Epithelium, what are Sustentacular cells?

Answer 10

• a form of epithelial cell
• act as metabolic and structural support

Question 11

What is the terminal bar in the Olfactory Epithelium?

Answer 11

• junctional complex connecting adjacent epithelial cells on the lateral surface
• examples include zonula occludens and zonula adherens

Question 12

What is a Bowmans gland located in the Olfactory Epithelium?

Answer 12

• mucosubstance secreting gland
• secrete mucous or serrous fluid
• secretes onto luminal/apical surface of the olfactory epithelium

Question 13

What are the basal cells of the Olfactory Epithelium?

Answer 13

• epithelial basal cells
• able to differentiate into sustentacular or olfactory cells

Question 14

What is the purpose of the sustentacular cells microvillia located in the Olfactory Epithelium?

Answer 14

• increase surface are of the Olfactory Epithelium
• they hold onto smell molecules until can bind with olefactory cilia
• microvillia like in the GIT, but here they are motile

Question 15

What are the olfactory receptor cells of the Olfactory Epithelium?

Answer 15

• form of epithelial cell
• capable of binding odour molecules involved in smell

Question 16

What is the end of the olfactory receptor cells inside the olfactory epithelium called?

Answer 16

• olfactory knob
• attaches to nerve fibres

Question 17

What is the name given to the cilia located at the end of the olfactory receptor cells facing the lumen of the nasal cavity?

Answer 17

• olfactory cilia that bind odur molecules
• non motile

Question 18

What are the 3 major parts of the olfactory receptor cells, beginning with the basal side of the cell?

Answer 18

1 - olfactory receptor cell

2 - olfactory knob

3 - olfactory cilia (attached to olfactory knob)

Question 19

What is special about the end of the olfactory receptor cells based in the basal aspects of the cell?

Answer 19

• attached to olfactory bulb
• olfactory bulb attached to olfactory nerve fibres
• provide information to brain about smell

Question 20

Where in the lungs does gas exchange take place?

Answer 20

• anywhere beyond the terminal bronchioles

Question 21

What are Clara cells?

Answer 21

• form of epithelial cell
• non ciliated cells
• act as a stem cell

Question 22

Where are Clara cells generally found?

Answer 22

• distal respiratory bronchioles
• terminal and respiratory bronchioles

Question 23

What 2 things do Clare cells secrete?

Answer 23

• part of surfactant
• enzymes able to detoxify noxious substances

Question 24

What are the 3 main components of the alveoli?

Answer 24

1 - single layer of epithelial cells

2 - supporting tissue (elastic+collagenous fibres and the occasional fibroblast)

3 - blood vessels

Question 25

What are pneuomcytes?

Answer 25

- pneumo = lungs - cells of the alveoli

Question 26

What are the 2 types of pneuomcytes of the alveoli?

Answer 26

- type 1 = squamous epithelial cells acting as a barrier - type 2 = cuboidal epithelial cells secreting surfactant

Question 27

Are there more type 1 or 2 pneuomcytes in the alveoli?

Answer 27

- type 1, but type 2 are a lot bigger

Question 28

What are the pores of Kohn?

Answer 28

- holes in adjacent alveoli - connection between alveoli

Question 29

What are the benefits of the pores of Kohn?

Answer 29

- allow air to move between alveoli - maintain homeostasis

Question 30

What are the risks of the pores of Kohn?

Answer 30

- allow infection spread between alveoli

Question 31

What term is used to describe patients who are prone to the triad of asthma, eczema and hayfever?

Answer 31

- atopic

Question 32

What does paroxysmal mean?

Answer 32

- sudden short attacks of a symptom or condition

Question 33

What is the main cause of COPD?

Answer 33

- smoking

Question 34

What is chronic bronchitis?

Answer 34

- chronic irritation of bronchial mucosa

Question 35

What is the clinical diagnosis of chronic bronchitis?

Answer 35

- sputum production most days - \>3months for 2 consecutive years

Question 36

In chronic bronchitis what happens to the bronchial mucosa?

Answer 36

- becomes thickened - form of COPD so obstructive lung disease

Question 37

What are some common causes of chronic irritation involved in chronic bronchitis?

Answer 37

- smoking (main cause) - pollutants - recurrent infection

Question 38

What are the most common changes to the bronchi in chronic bronchitis and chronic asthma?

Answer 38

- inflammatory cells infiltrate submucosa - hypertrophy of smooth muscle - mucosal cell hyperplasia and ⬆️ mucus production - squamous cells metaplasia (columnar change to sqaumous)

Question 39

What is emphysema?

Answer 39

- chronic irritation and inflammation of respiratory zone - permanent enlargement of respiratory zone - form of COPD

Question 40

How does emphysema cause a permanent enlargement of the respiratory zone?

Answer 40

- alveoli can collapse, narrow and generally not function - ⬇️ surface area - air sacs merge and form bullae

Question 41

What is pulmonary fibrosis?

Answer 41

- scarring of the lungs - restrictive lung disease

Question 42

What happens to the alveolar walls in pulmonary fibrosis?

Answer 42

- ⬆️ thickness due to collagen deposition - ⬆️ fibrosis - ⬆️ in type 2 pneuomcytes

Question 43

What is pneumoconioses, also known as occupational lung disease?

Answer 43

- interstitial lung damage caused by irritants - generally inorganic dusts - can cause fibrosis

Question 44

What does pneumoconioses, also known as occupational lung disease do to the interstitial aspects of the lungs?

Answer 44

- fibrosis in lungs - ⬆️ thickness of interstitial space - ⬇️ perfusion

Question 45

Silica dust has been shown to cause pneumoconioses, also known as occupational lung disease. What happens to the macrophages in patients who inhale silica dust for long periods?

Answer 45

- phagocytosed by macrophages - formation of granuloma like masses around macrophage containing silica - macrophages containing silica induce fibrotic reactions - nodules form of collagenous tissue

Question 46

Why is asbestos so dangerous?

Answer 46

- small like fibres can enter airways - coated with proteinaceous material forming asbestos bodies - macrophages and giant cells infiltrate and cause fibrosis

Question 47

What is the most common cancer in patients exposed to long term asbestos?

Answer 47

- mesothelioma

Question 48

What are the 2 groups of lung cancer/neoplasms?

Answer 48

- small cell lung carcinoma - non-small cell lung carcinoma

Question 49

What % of lung cancer/neoplasms are caused by - small cell lung carcinoma and non-small cell lung carcinoma?

Answer 49

- small cell lung carcinoma = 20% - non-small cell lung carcinoma = 80%

Question 50

What are the 3 subdivisions of non-small cell lung carcinoma?

Answer 50

1 - squamous cell carcinoma 2 - adenocarcinoma 3 - large cell carcinoma

Question 51

Are benign tumours in the lungs common?

Answer 51

- no - they are rare

Question 52

What cells do small cell lung carcinomas generally originate from?

Answer 52

- neuroendocrine cells that differentiate

Question 53

On histology how do small cell lung carcinomas appear?

Answer 53

- darkly stained - crushed and tightly packed together

Question 54

Is small cell lung carcinomas responsive to treatment?

Answer 54

- yes - generally too late to treat when diagnosed though - highly malignant and metastasised

Question 55

Squamous cell carcinomas are a form of non-small cell lung carcinomas, where do they generally start?

Answer 55

- affect squamous cells - main bronchi