13. Lung and the Environment

Question 1

a few forces that control particle deposition in the lungs

Answer 1

• inertia/impaction: tendency to fail to turn corners of R tract, impact upon nose, pharynx, bifurcations
• sedimentation: particles settle acc to their weight
• diffusion (random movement)

Question 2

characteristics that modify particle deposition?

Answer 2

• breathing pattern

- anatomy of the resp tract

Question 3

a few defense mechanisms we have against inhaled substances?

Answer 3

• physical barriers (ie nose filtration)
• mucociliary clearance
• alveolar clearance
• cough
• immune system

Question 4

describe mucociliary clearance

Answer 4

active from resp bronchiole to larynx. coordinated activity of ciliated epithelium. epit cells covered with a fluid bilayer, with both solution phase and gel phase. sol phase facilitates ciliary beat.

Question 5

how quickly do most normal people clear inhaled particles from the bronchi?

Answer 5

6 hrs

Question 6

what phase of mucociliary clearance does cystic fibrosis disrupt (sol or gel)?

Answer 6

sol

Question 7

what phase of mucociliary clearance does chronic bronchitis disrupt (sol or gel)?

Answer 7

gel

Question 8

what phase of mucociliary clearance does Kartagener’s syndrome disrupt?

Answer 8

cilia

Question 9

describe alveolar clearance

Answer 9

non ciliated regions. particles transported by alveolar macrophages to mucociliary laler of lymphatic system.

Question 10

what does the ability to cough depend on?

Answer 10

the presence of intact upper and lower afferents and reflex efferents, resp muscles, larynx

Question 11

what are some examples of diseases caused by inspired substances?

Answer 11

silicosis, coal worker’s pneumoconiosis, asbestos-related lung disease, farmer’s lung, malt worker’s lung

Question 12

where does asbestos exposure occur?

Answer 12

mining, home insulation, production of fireproof textiles, paints, brake and clutch linings

Question 13

what usually occurs with inorganic dust diseases (pneumoconiosis)?

Answer 13

parenchymal inflammation, fibrosis due to the tissue reactions involved in trying to clear organic dusts

Question 14

besides interstitial fibrosis, another major lung disease that people exposed to asbestos can present with?

Answer 14

cancer. smoking + asbestos exposure together is terrible.

Question 15

what is organic dust disease? what are the 2 types of immune responses it causes?

Answer 15

hypersensitivity.
two types:
-hypersensitivity pneumonitis (ex farmer’s lung)
-occupational asthma (ex cereal worker’s lung)

Question 16

Features of hypersensitivity pneumonitis?

Answer 16

systemic reaction, fever, crackles, restrictive pattern.

Question 17

Features of occupational asthma?

Answer 17

dyspnea/wheezing at work, may have latent period of several hours. cough, sputum may improve weekends and vacations.

Question 18

what is aspiration?

Answer 18

normal people aspirate frequently. clinical meaning of aspiration is inhaling a usually non-respirable particle with subsequent disease

Question 19

what are 2 mechanisms of aspiration?

Answer 19

• impaired neuromotor function (anesthesia, depressed lungs, alcohol)
• altered anatomy

Question 20

what is the difference between mainstream and sidestream smoke?

Answer 20

mainstream produced when smoker draws on cig. predominant source for smoker.
sidestream = when cig smolders. predominant env source

Question 21

what does nicotine do in the body?

Answer 21

binds to acetylcholine receptors at autonomic ganglia, adrenal medulla, NM junction and brain.

Question 22

what are the effects of nicotine in the body?

Answer 22

stimulates hormone release: catecholamines, ACTH.
inc heart rate, BP, CO
mental stimulation, relaxation, enhanced learning, memory, attention.
promotes thrombosis, plate agg and vasospasm

Question 23

what % of americans smoke?

Answer 23

23%

Question 24

what cancers does smoking contribute to?

Answer 24

lung, also oral cav, larynx, esophagus, bladder, kidney, panc, stomach, cervix

Question 25

what cardiac problems are caused by smoking?

Answer 25

atherosclerosis, incl coronary artery disease, CV disease, peripheral vasc disease

Question 26

what main resp diseases are caused by smoking?

Answer 26

COPD (chron bron, emphy)

Question 27

definition of invol smoking?

Answer 27

exposure of non-smokers to tobacco combustion products in the indoor envt

Question 28

chronic effects of invol smoking in children?

Answer 28

freq of acute resp illness (asthma, chronic cough, sputum, wheezing) in children 5-20 yo

Question 29

effect of parental smoking on kids asthma?

Answer 29

increased incidence

Question 30

smoking cess programs long-term success rate is approx what %?

Answer 30

20%

Question 31

4 benefits of smoking cessation

Answer 31

1. inc life expectancy 2. slowing of progression of tobacco related disease 3. decr risk of lung cancer 4. reduction in perioperative resp complications

Question 32

water soluble agents: where do they do damage?

Answer 32

they dissolve in upper resp tract. injure immediate air spaces (nose, throat, bronchi).

Question 33

water insoluble agents: where do they do damage?

Answer 33

more distal, alveoli, bronchioli

Question 34

water insoluble agents: why delay in recognition?

Answer 34

lack of deposition on mucosal surfaces. symptoms delayed 3-30 hrs

Question 35

factors affecting particle deposition

Answer 35

- impaction - sedimentation - diffusion

Question 36

why do we advise people taking inhalers to inhale slowly?

Answer 36

to minimize impaction. also they hold their breath afterwards to allow time for sedimentation (so they don't exhale the med)

Question 37

what is relevant about Kartagener's syndrome?

Answer 37

structural abnormality of cilia

Question 38

definition of pneumoconiosis?

Answer 38

lung disease caused by inhalation of inorganic dusts

Question 39

what is silicosis?

Answer 39

one type of pneumoconiosis. | Lung disease secondary to inhalation of silicon dioxide

Question 40

2 types of silicosis?

Answer 40

Simple silicosis: generally a radiographic abnormality (nodules), unaccompanied by change in lung function, impairment or disability, or decreased longevity Progressive massive fibrosis: formation of large, coalescent masses that obliterate lung structure

Question 41

coal worker's pneumoconiosis: difference from silicosis?

Answer 41

only difference is type of dust. CWP may present mosaic. nodules, focal emphysema

Question 42

definition of asbestosis?

Answer 42

interstitial lung disease associated with asbestos exposure. may yield a pleural plaque (plates of calcium at lung border on cxr)

Question 43

definition of hypersensitivity pneumonitis?

Answer 43

Immunologically mediated lung disease (secondary to inhaled organic dust) Caused by intense and/or repeated exposure of dusts that reach distal lung units Same clinical and pathologic findings regardless of organic dust involved Acute exposure: flu-like symptoms + breathlessness within hours Chronic exposure: insidious onset of respiratory symptoms, possibly with irreversible fibrosis

Question 44

a few causes of hypersensitivity pneumonitis?

Answer 44

Malt worker's disease Farmer's Lung Tea grower's disease

Question 45

a few causes of occupational asthma?

Answer 45

cereal dust wood dust animal proteins

Question 46

what drugs are best to support smoking cessation?

Answer 46

- varenicline - Partial agonist for α4β2 nicotinic acetylcholine receptor which may play a role in addiction - more successful than buproprion or placebo