Lecture 10 - Respiratory System and CF Flashcards Preview

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Flashcards in Lecture 10 - Respiratory System and CF Deck (74):
1

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

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

2

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

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

3

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

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

4

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

Embryonic

5

Which time is the embryonic period of lung development?

0 to 6 weeks gestation

6

Which time is the pseudoglandular period of lung development?

6 to 16 weeks gestation

7

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

Pseudoglandular

8

Which time is the canalicular period of lung development?

16 to 26 weeks gestation

9

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

Canalicular

10

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

26 to 36 weeks gestation

11

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

Sacular/alveolar

12

Which stage of lung development is between birth and teenagehood?

Postnatal

13

When do lung buds first appear?

Day 20-26 (embryonic period)

14

Which germ layer do the lungs originate from?

Endoderm

15

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

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

16

What happens in the pseudoglandualr period?
1)
2)

1) Airways branch until terminal bronchioles
2) This entails 16 divisions of airways

17

What are terminal bronchioles?

Pre-acinar bronchi

18

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

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

19

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

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

20

Number of alveoli at birth

10^8

21

Number of alveoli in adulthood

3 x 10^8

22

Lung surface area at birth

4M squared

23

Lung surface in adulthood

10M squared

24

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

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

25

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

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

26

Airways surface liquid layers
1)
2)

1) Periciliary layer
2) Mucus layer

27

What coats the mucociliary elevator?

Airways surface liquid

28

Rate of mucus movement in mucociliary elevator

~1mm/minute

29

What secrete mucus in airways?

Goblet cells

30

Function of type I pneumocytes

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

31

Function of type II pneumocytes

Surfactant secretion

32

How can O2 more easily cross between alveoli and blood?

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

33

Lung volume used at rest

Tidal volume

34

Amount of air that you can breathe in over tidal volume

Inspiratory reserve

35

Amount of air you can breathe out under tidal volume

Expiratory reserve

36

What is inspiratory capacity?

Inspiratory reserve + Tidal volume

37

What is vital capacity?

Inspiratory reserve + Expiratory reserve + Tidal volume

38

What is residual volume?

Amount of air in lungs that can not be exhaled

39

What is functional residual capacity?

Expiratory capacity + Residual volume

40

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

Residual volume

41

What is inspiratory reserve + tidal volume?

Inspiratory capacity

42

What is inspiratory reserve + expiratory reserve + tidal volume?

Vital capacity

43

What is expiratory capacity + residual volume?

Functional residual capacity

44

What is FEV1?

Volume exhaled in 1 second

45

What is forced vital capacity?

Total volume exhaled in spirometry

46

What is the total volume exhaled in spirometry?

Forced vital capacity (FVC)

47

How is lung capacity measured?

With a spirometer
FEV1

48

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

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

49

Main cause of morbidity and mortality in CF

Lung infections

50

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

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)

51

Important CFTR function in normal lung

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.

52

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

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

53

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

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

54

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

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

55

Which two important antioxidants does CFTR regulate?

Glutathione
Thiocyanate

56

Result of impaired CFTR regulation of glutathione and thiocyanate

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

57

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

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

58

Bacterium which likes to grow in anaerobic parts of CF lungs

Pseudomonas aeruginosa

59

Which type of inflammation is predominant in CF?

Neutrophilic inflammation

60

Lung defence against neutrophil-released proteaes

Antiproteases
Overwhelmed with large neutrophil response in CF

61

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

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

62

What is ceramide?

A secondary messenger, a breakdown product of sphingomyelin, which is found in cell membranes, endosomal walls

Excess ceramide leads to apoptosis

63

What is bronchiectasis?

Dilation of bronchi

64

What is dilation of bronchi called?

Bronchiectasis

65

Common pathogen in children with CF

Staph aureus

66

Common pathogens in adults with CF

Pseudomonas
Burkholderia cepacia
Stenotrophomonas maltophillia

67

Rising microbe infecting CF lungs

Mycobacteria abcessis
Resistant to many drugs

68

What does 100% lung function mean?

Mean lung function for a population

69

Normal range of lung functions

80% - 120% lung function

70

When does CF lung function begin to deteriorate?

Around teenage years

71

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

Ceramide

72

What information foes FVC give?

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

73

Proportion of CF mortality and morbidity caused by lung disease

90%

74

Airway surface liquid volume regulation

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.