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Flashcards in 2. Pneumocytes Deck (25):
1

Pneumoncytes types

Type I
Type II
Club cells

2

Pneumonocytes - porportion of alveolar surface

97% type I celll

3

type I cell pneymonocytes area

line the alveoli

4

type I cell pneumonocytes - histology

1. squamous
2. thin

5

type I pneymonocytes are thin because...

optimal gas exchange

6

type II cell pneumonocytes - histology

cuboidal and clustered

7

Type II pneumonocytes function

1. secrete pulmonary surfactant
2. serve as precyrsor to type I cells and other type II cells - they can proliferate during damage

8

Pulmonary surfactan is secreted by

type II cell pneumonocyte
2. Club (Clara ) cells

9

pulmonary surfactan - fumctopm

decreases alveolar surface tension and prevents alveolar collapse (atelactasis (decrease recoil and increased compliance

10

Club clara cells - histology

nonciliated
low columnar /cuboidal with secretory granules

11

Club (clara cells - function

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

12

lung - collapsing pressure (P) equation

P= 2 (surface tension) / radius

13

Laplace law in alveoli

alveoli have increased tendency to collapse on expiration as radius decreases

14

Pulmonary surfactant is a (chemistry)

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

15

Pulmonsty surgactant : mature levels achieved

around week 35

16

Pulmonary surfactant synthesis begins

around week 26 of gestation

17

• What is the advantage of having numerous thin type I pneumocytes line the walls of alveoli?

Maximum gas exchange is permitted by thin cells (squamous morphology)

18

What are two important functions of type II pneumocytes?

To secrete surfactant (prevent alveolar collapse) and to serve as precursors to other pneumocytes (both types I and II)

19

• A patient suffers a pneumothorax, which damages his lungs. Which cells proliferate to repair the lungs after they have been damaged?

Type II pneumocytes (they are the precursors of both type I and type II pneumocytes)

20

Describe club cells and their three functions. What is another (now outdated) name for them?

Nonciliated columnar/cuboidal pneumocytes with secretory granules that secrete surfactant, degrade toxins, act as reserve cells; Clara cells

21

Explain the law of Laplace using the equation for calculating collapsing pressure (P).

P = 2 (surface tension)/radius; alveoli have a tendency to collapse on expiration, because as their radius decreases, P increases

22

What is dipalmitoylphosphatidylcholine? What is its function?

A type of lecithin and an important component of surfactant; surfactant decreases alveolar surface tension and prevents atelectasis

23

A neonate is born at 32 weeks. Why will this neonate have respiratory problems?

Surfactant synthesis starts at 26 weeks but does not mature until 35 weeks—therefore, the child is more likely to have respiratory distress

24

A woman at 30 weeks' gestation presents for an exam. The ratio of which two amniotic fluid markers can be used to assess fetal lung maturity?

The lecithin:sphingomyelin ratio (marker for surfactant quantity)

25

A lecithin:sphingomyelin ratio is derived for a neonate to evaluate fetal lung maturity. What value is indicative of lung maturity?

Ratio >2.0