Lecture 10 - Respiratory System and CF

Question 1

Order of branches in the lungs
1)
2)
3)
4)
5)
6)
7)
8)

Answer 1

1) Upper airways
2) Trachaea
3) Bronchi
4) Bronchioles
5) Terminal bronchioles
6) Respiratory bronchioles
7) Alveolar ducts
8) Alveoli

Question 2

What are acini? (singular: acinus)
1)
2)
3)
4)

Answer 2

1) Respiratory bronchioles
2) Alveolar ducts
3) Alveolar sacs
4) Alveoli

Question 3

Stages of lung development
1)
2)
3)
4)
5)

Answer 3

1) Embryonic
2) Pseudoglandular
3) Canalicular
4) Sacular/Alveolar
5) Postnatal

Question 4

Which lung development period is between 0 and 6 weeks of gestation?

Answer 4

Embryonic

Question 5

Which time is the embryonic period of lung development?

Answer 5

0 to 6 weeks gestation

Question 6

Which time is the pseudoglandular period of lung development?

Answer 6

6 to 16 weeks gestation

Question 7

Which stage of lung development is between 6 and 16 weeks development?

Answer 7

Pseudoglandular

Question 8

Which time is the canalicular period of lung development?

Answer 8

16 to 26 weeks gestation

Question 9

Which stage of lung development is between 16 and 26 weeks of gestation?

Answer 9

Canalicular

Question 10

Which time is the sacular/alveolar period of lung development?

Answer 10

26 to 36 weeks gestation

Question 11

Which stage of lung development is between 26 and 36 weeks of gestation?

Answer 11

Sacular/alveolar

Question 12

Which stage of lung development is between birth and teenagehood?

Answer 12

Postnatal

Question 13

When do lung buds first appear?

Answer 13

Day 20-26 (embryonic period)

Question 14

Which germ layer do the lungs originate from?

Answer 14

Endoderm

Question 15

What happens in the embryonic period?
1)
2)
3)

Answer 15

1) Lung buds form
2) Ventral outpouching of primitive foregut
3) Endoderm pushes out proximally into surrounding mesoderm

Question 16

What happens in the pseudoglandualr period?
1)
2)

Answer 16

1) Airways branch until terminal bronchioles

2) This entails 16 divisions of airways

Question 17

What are terminal bronchioles?

Answer 17

Pre-acinar bronchi

Question 18

What happens in the canalicular period?
1)
2)
3)

Answer 18

1) Acini form
2) Epithelium thins
3) Pneumocytes form (type I and type II)

Question 19

What happens in the sacular/alveolar period?
1)
2)
3)
4)

Answer 19

1) Sacules form into alveolar ducts and alveoli
2) Interstitial tissue decreases markedly
3) Septation of alveoli makes more alveoli
4) Walls of sacules become thin

Question 20

Number of alveoli at birth

Answer 20

10^8

Question 21

Number of alveoli in adulthood

Answer 21

3 x 10^8

Question 22

Lung surface area at birth

Answer 22

4M squared

Question 23

Lung surface in adulthood

Answer 23

10M squared

Question 24

Functions of the lungs
1)
2)
3)
4)
5)
6)
7)

Answer 24

1) Gas exchange
2) Defence
3) Acid-base balance
4) Heat exchange
5) Water balance
6) Phonation
7) Metabolic

Question 25

``` Lung defence mechanisms 1) 2) 3) 4) 5) ```

Answer 25

1) Upper airway filter 2) Reflexes (sneeze, cough) 3) Mucociliary elevator 4) Alveolar macrophages 5) Surfactant

Question 26

Airways surface liquid layers 1) 2)

Answer 26

1) Periciliary layer | 2) Mucus layer

Question 27

What coats the mucociliary elevator?

Answer 27

Airways surface liquid

Question 28

Rate of mucus movement in mucociliary elevator

Answer 28

~1mm/minute

Question 29

What secrete mucus in airways?

Answer 29

Goblet cells

Question 30

Function of type I pneumocytes

Answer 30

Make wall of alveoli | Across these O2 is exchanged with alveolar capillaries

Question 31

Function of type II pneumocytes

Answer 31

Surfactant secretion

Question 32

How can O2 more easily cross between alveoli and blood?

Answer 32

Fused basal laminae of type I pneumocyte and endothelial wall of alveolar capillary

Question 33

Lung volume used at rest

Answer 33

Tidal volume

Question 34

Amount of air that you can breathe in over tidal volume

Answer 34

Inspiratory reserve

Question 35

Amount of air you can breathe out under tidal volume

Answer 35

Expiratory reserve

Question 36

What is inspiratory capacity?

Answer 36

Inspiratory reserve + Tidal volume

Question 37

What is vital capacity?

Answer 37

Inspiratory reserve + Expiratory reserve + Tidal volume

Question 38

What is residual volume?

Answer 38

Amount of air in lungs that can not be exhaled

Question 39

What is functional residual capacity?

Answer 39

Expiratory capacity + Residual volume

Question 40

What is the air that can not be breathed out of the lungs?

Answer 40

Residual volume

Question 41

What is inspiratory reserve + tidal volume?

Answer 41

Inspiratory capacity

Question 42

What is inspiratory reserve + expiratory reserve + tidal volume?

Answer 42

Vital capacity

Question 43

What is expiratory capacity + residual volume?

Answer 43

Functional residual capacity

Question 44

What is FEV1?

Answer 44

Volume exhaled in 1 second

Question 45

What is forced vital capacity?

Answer 45

Total volume exhaled in spirometry

Question 46

What is the total volume exhaled in spirometry?

Answer 46

Forced vital capacity (FVC)

Question 47

How is lung capacity measured?

Answer 47

With a spirometer | FEV1

Question 48

Difference between normal flow-volume curve and CF flow-volume curve

Answer 48

With CF, expiratory flow drops very quickly, a airways are narrower. Takes longer to empty, reinflate lunge

Question 49

Main cause of morbidity and mortality in CF

Answer 49

Lung infections

Question 50

``` Which cell types in the lungs is CFTR expressed on? 1) 2) 3) 4) 5) ```

Answer 50

1) Ciliated epithelial cells 2) Serous cells of submucosal glands 3) Alveolar type II pneumocytes 4) Alveolar macrophages 5) Neutrophils (role on macrophages and neutrophils not well understood)

Question 51

Important CFTR function in normal lung

Answer 51

Modulate airway surface liquid By Cl- secretion, inhibiting Na+ absorption (by inhibiting ENaC) ASL reabsorption occurs by ENaC actively taking Na+ into epithelial cell, with Cl- moving passively after When ASL is depleted, CFTR transports Cl- out of epithelial cell and inhibits ENaC from removing Na+ from lungs.

Question 52

``` What happens in CF to airway surfactant liquid? 1) 2) 3) 4) ```

Answer 52

1) Cl- can't exit type I pneumocytes 2) EnAC Na+ reabsorption isn't inhibited by CFTR. 3) This results in higher osmotic pressure in pneumocyte 4) Water enters pneumocyte, airway surface liquid is dehydrated, decreases in volume

Question 53

Result of decreased airways surfactant liquid volume 1) 2) 3)

Answer 53

1) Mucus layer sits on cilia, preventing cilia from beating 2) Mucus isn't lubricated, so forms plaque on ciliated epithelium 3) Bacteria colonise newly-formed anaerobic environment

Question 54

How can antimicrobial function be impaired in CF airways? 1) 2) 3)

Answer 54

1) Defective CFTR transport of bicarbonate, pH regulation 2) Inhibits correct function of immune system in airways 3) CFTR might be involved in binding microbes, drawing them into epithelial cells to be killed

Question 55

Which two important antioxidants does CFTR regulate?

Answer 55

Glutathione | Thiocyanate

Question 56

Result of impaired CFTR regulation of glutathione and thiocyanate

Answer 56

Glutathione and thiocyanate are important antioxidants | Increases oxidative stress in airways, leading to inflammation

Question 57

How is an anaerobic environment formed in CF airways? 1) 2)

Answer 57

1) Mucus plaque formed | 2) Ciliated epithelium uses more oxygen, as has to work harder

Question 58

Bacterium which likes to grow in anaerobic parts of CF lungs

Answer 58

Pseudomonas aeruginosa

Question 59

Which type of inflammation is predominant in CF?

Answer 59

Neutrophilic inflammation

Question 60

Lung defence against neutrophil-released proteaes

Answer 60

Antiproteases | Overwhelmed with large neutrophil response in CF

Question 61

``` Cause of lung inflammation in CF 1) 2) 3) 4) 5) ```

Answer 61

1) Bacteria grow in anaerobic environments, byproducts include oxygen radicals 2) Oxygen radicals breathed in normally 3) Neutrophils release radical oxygen species, might be overactive in CF 4) Accumulation of abnormally-folded CFTR in cells can lead to apoptosis 5) Abnormal intracellular processes of epithelial cells lead to cell stress, release of cytokines

Question 62

What is ceramide?

Answer 62

A secondary messenger, a breakdown product of sphingomyelin, which is found in cell membranes, endosomal walls Excess ceramide leads to apoptosis

Question 63

What is bronchiectasis?

Answer 63

Dilation of bronchi

Question 64

What is dilation of bronchi called?

Answer 64

Bronchiectasis

Question 65

Common pathogen in children with CF

Answer 65

Staph aureus

Question 66

Common pathogens in adults with CF

Answer 66

Pseudomonas Burkholderia cepacia Stenotrophomonas maltophillia

Question 67

Rising microbe infecting CF lungs

Answer 67

Mycobacteria abcessis | Resistant to many drugs

Question 68

What does 100% lung function mean?

Answer 68

Mean lung function for a population

Question 69

Normal range of lung functions

Answer 69

80% - 120% lung function

Question 70

When does CF lung function begin to deteriorate?

Answer 70

Around teenage years

Question 71

What is a breakdown product of sphingomyelin, involved in apoptosis?

Answer 71

Ceramide

Question 72

What information foes FVC give?

Answer 72

Total lung capacity | Doesn't give information about narrowing of airways

Question 73

Proportion of CF mortality and morbidity caused by lung disease

Answer 73

90%

Question 74

Airway surface liquid volume regulation

Answer 74

1) When ASL levels are too high - ENaC actively pumps Na+ into cell. Cl- follows passively. 2) When ASL levels are too low - CFTR inhibits ENaC. Cl- pumped out of cell.