alveoli and pulmonary capillaries

1

nucleus of type I alveolar cell

2

alveolar pores

3

capillary

4

alveolar macrophages

5

endothelial cell nucleus

6

respiratory membrane

7

alveoli

8

red blood cell in capillary

9

type II alveolar cell

10

type I alveolar cell

11

alveolus

12

endothelial cell nucleus

13

alveolar epithelium

14

fused basement membranes

15

capillary endothelium

16

nucleus of type I

17

red blood cell

18

O2

19

CO2

20

alveolus

21

capillary