Introduction/Structure of the Respiratory System

Ventilation (breathing)

mechanical process that moves air into and out of the lungs

Gas exchange

between blood and lungs and between blood and tissues

How is oxygen utilized?

by tissues to make ATP (cellular respiration)

Ventilation and gas exchange in lungs =

external respiration

Oxygen utilzation and gas exchange in tissues

internal respiration

What consists in gas exchange in the lungs?

occurs via diffusion, O2 is higher in the lungs than in the blood (therefore diffuses into the blood), CO2 in higher in the blood than lungs (diffuses out of the blood)

What is the alveoli?

air sacs in the lungs where gas exchange occurs; 300 million of them

What are the characteristics of the alveoli?

each one of these is one-cell layer thick but has great tensile strength; form clusters at the ends of respiratory bronchioles

Type 1 alveolar cells

gas exchange occurs; 97-95% total surface area

Type 2 alveolar cells

make surfactant; reabsorb sodium and water; prevent fluid buildup

Surfactant

decreases surface tension

Surface tension

the force exerted by water molecules on the surface of lung tissue as the water molecules pull together

What is the conduction zone?

gets air to the respiratory zone + producing voice

What is the respiratory zone?

site of gas exchange

What are the functions of the conducting zone?

transports air to respiratory zone, voice production, warms, humidfies, filters and cleans the air; moves mucus by cilia