respiratory tree - pneumocytes

Question 1

Respiratory tree - 2 zones

Answer 1

1. conducting zone

2. Respiratory zone

Question 2

conducting zones consist of

Answer 2

1. large airways (nose, pharynx, larynx, trachea, bronchi)

2. small airways (small bronchioles, terminal bronchioles)

Question 3

conducting zones - large airways

Answer 3

1. nose
2. pharynx
3. larynx
4. trachea
   5/ bronchi

Question 4

conducting zones - small airways (and characteristic)

Answer 4

terminal bronchioles –> large number in paraller –> least airway resistance

Question 5

least airway resistant (why)

Answer 5

terminal bronchioles (LARGE NUMBER IN PARALLEL)

Question 6

conducting zones - function

Answer 6

warms, humidifies, and filters air but does not participate in gas exchange –> anatomic dead space

Question 7

conducting zone - histology

Answer 7

1. cartilage and goblet extent to end of bronchi
2. pseudostratified ciliated columnar cells extend to beginning of terminal bronchioles, then transition to cuboidal cells (clear mucus and debris (mucociliary elevator)
3. Airway SMCs extend to end of terminal bronchioles and sparse beyond this point

Question 8

pseudostratified ciliated columnar cells - function

Answer 8

clear mucus from lungs (mucociliary elevator)

Question 9

respiratory zone - function

Answer 9

it participates in gas exchange

Question 10

respiratory zone - consist of

Answer 10

Lung parenchyma (respiratory bronchioles, alveolar ducts, alveoli)

Question 11

Lung parenchyma consist of

Answer 11

respiratory bronchioles, alveolar ducts, alveoli

Question 12

respiratory zone - histology

Answer 12

• mostly cuboidal cells in respiratory bronchioles, then simple squamous cells up to alveoli
• Cilia terminate in respiratory bronchioles
• alveolar macrophages

Question 13

alveolar macrophages - function

Answer 13

clear debris and participate in immune response

Question 14

respiratory tree - area of cilia

Answer 14

terminate in respiratory bronchioles

Question 15

respiratory bronchioles histology - mostly cells in respiratory bronchioles

Answer 15

cuboidal cells

Question 16

respiratory tree - SMCs (area)

Answer 16

extend to end of terminal bronchioles and sparse beyond this point

Question 17

respiratory tree - pseudostratified ciliated columnar cells (area)

Answer 17

extend to beginning of terminal bronchioles

Question 18

respiratory tree - pseudostratified ciliated columnar cells extend to ….. and then transition to ….

Answer 18

• beginning of terminal bronchioles

- cuboidal cells

Question 19

cartilage extend to

Answer 19

end of bronchi

Question 20

goblet cells extend to

Answer 20

end of bronchi

Question 21

pneumocytes - types

Answer 21

• type I cells
• type II cells
• Club cells

Question 22

pneumocytes - proportion of alveolar surface

Answer 22

97% type I cell

Question 23

type I cell pneumocytes - area

Answer 23

line the alveoli

Question 24

type I cell pneumocytes - histology

Answer 24

1. squamous

2. thin

Question 25

type I cell pneumocytes are thin - purpose

Answer 25

optimal gas exhange

Question 26

type II cell pneumocytes - function and histology

Answer 26

histology: cuboidal and clustered
1. secrete pulmonary surfactant
2. serve as precursor to type I cells and other type II cellls - they can proliferate during damage

Question 27

pulmonary surfactant is secreted by

Answer 27

1. type II cell pneumocytes

2. Club (Clara) cells

Question 28

pulmonary surfactant - function

Answer 28

decreases alveolar surface tension and prevents alveolar collaplse (atelactasis) (decreased recoil and increased compliance)

Question 29

atelactasis - definition

Answer 29

alveolar collapse

Question 30

Club (Clara) cells - histology

Answer 30

Nonciliated

low-columnar/cuboidal with secretory granules

Question 31

Club (Clara) cells - function

Answer 31

1. secrete component of surfactant
2. degrade toxins
3. act as reserve cells

Question 32

lung - collapsing pressure (P) equation

Answer 32

P = 2(surface tension)/radius

Question 33

Laplace law in alveoli

Answer 33

alveoli have increased tendency to collapse on expiration as radius decrease

Question 34

Pulmonary surfactant is a (chemistry)

Answer 34

compxex mix of lecithins, the most important of which is dipalmitoylphosphatidycholine

Question 35

Pulmonary surfactant synthesis by time

Answer 35

begins around week 26 of gestation, but mature levels are not achieved until around week 35

Question 36

Pulmonary surfactant synthesis begins (time)

Answer 36

around week 26 of gestation

Question 37

Pulmonary surfactant: mature levels are achieved at (time)

Answer 37

around week 35

Question 38

Screening test for fetal lung maturity

Answer 38

1. lecithin/sphingomyelin ration in amniotic fluid –>
   - if more than 2 –> healthy
   - if less than 1.5 –> predictive of NRDAS
2. foam stability test
3. surfactant/albumin ratio

Question 39

pseudostratified ciliated cells extend (area)

Answer 39

to beginning of terminal bronchioles

Question 40

most frequent cells in respiratory bronchioles

Answer 40

cuboidal cells

Question 41

respiratory tree - cuboidal cells (area)

Answer 41

terminal and respiratory bronchioles

Question 42

type II cell pneumocytes - histology

Answer 42

cuboidal and clustered

Question 43

Pulmonary surfactant synthesis by time

Answer 43

begins around week 26 of gestation, but mature levels are not achieved until around week 35

Question 44

foam stability test?

Answer 44

Mix equal parts of amniotic fluid with 95% ethanol:

• bubbles present –> (+)
• bubbles absent –> (-)