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Gas Exchange

breathing system

trachea

Intercostal muscle

Bronchi

bronchioles

alveoli

Diaphragm

ventilation

inhalation

expiration

alveoli in lungs

contraction of muscles

maintaining concentration gradients

lung cancer

Ephysema

irreversible chronic disease because of the damage of the alveoli

smoking, chest infections, and air pollution

abnormal cell growth causing tumors in lungs

smoking mainly, but also air pollution, exposure to radon gas, genetics

Pneumocytes

type I

cells with small thickness of cytoplasm

CO2

O2

diffusion

type II

cells that secrete fluids containing surfactant

allows oxygen in the alveoli to dissolve and then diffuse