Human Lungs

We exchange gas in…

alveoli

Human Respiratory System: Conduction Zone

Only moves air

1.) Trachea

2.)Brinchial Tree

3.)Bronchioles

4.)Terminal Bronchioles

Human Respiratory System: Respiratory Zone

1.) Respiratory Bronchioles (begin gas exchange because of alveoli)

2.) Alveolar Sacs (alveoli)

Thoracic Cavity Structures (3)

-Visceral Pleural Membrane

-Pleural Cavity

-Parietal Pleural Membrane

THoracic Cavity

hold/separates lungs

Parietal Pleural Membrane

outside

Visceral Pleural Membrane

holds lung intimately and sirus

Alveolus Cells Type I

gas exchange

Alveolus Cells Type II

surgactin production

Talking about a closed space, if I apply a pressure that expands that space, what will happen to the pressure in that pleural sac?

go down

Respiratory membrane pathway for gas exchange

-Lung Surface: epithelial type I cell → epithelial basement membrane

-Interstitium

-Blood Vessel: endothelial basement membrane → endothelial cell

Ventilation Pressures (4)

-Atmospheric
-Intrapleural : pressure in plural space
-Transpulmonary Pressure: pressure difference from pleural sac and alveoli
-Intraaveolar Pressure: pressure in alveolar pocket

Mechanics of Inspiration (7)

1.) Diaphragm, chest wall muscles contract (active)

2.)Volume of thoracic cavity increases

3.)Intrapleural pressure decreases

4.) Tranpulmonary pressure increases (un-out)

5.) Lung inflates

6.) Intraalveolar pressure drops below atmospheric pressure

7.) Air enters lungs

Lung Properties: Elasticity

Able to return to shape after being distorted (inflated)

Lung Properties: Distensubility

Ability to stretch

Lung Properties: Compliance

volume change occurred in lung compared to pressure difference that cause that to occur

Closed System Lung Inflation:
-Intrapleural Pressure_______

Decreases

Change in transpulmonary pressure (increases) inflates the lung NOT the _______

alveolar pressure (decreases)

Increase in intraaveolar pressure =

air out

(drop,drop,drop, inc = air out) and vice versa

Describe

-Normal=left
-Abnormally high (overly complaint): easy to inflate, hard to deflate
- like emphysema
-Abnormally low in compliance: easy to deflate and hard to inflate
- elasticity changes when older (less       compliance)

If I take alveoulus and line it with water, as I decrease the volume, what is happening with the water molecules?

surface tension is going to go up

If surface tension goes up, how hard is it going to be to inflate alveoulus again?

Hard
Surfactan: mixes with water surface to help reduce surface tension => lung easier to inflate