1. The Human Respiratory System
Definition: A group of organs working together to bring about the exchange of oxygen (O2) and carbon dioxide (CO2) with the environment.
Bill Nye on Respiration

2. Anatomy of the Respiratory System
Nose
Nasal Cavity
Pharynx
Larynx
Trachea
Left Bronchus
Right Bronchus
Left Lung
Right Lung
Bronchioles and Alveoli
Diaphragm

3. Pharynx: Located at the back of mouth
Pharynx: Located at the back of mouth. Serves as a passageway for both air and food.
Pharynx

4. Trachea: Also known as the windpipe. Leads to the lungs
Trachea: Also known as the windpipe. Leads to the lungs. Filters dust, dirt, smoke etc.
Trachea

5. Larynx - Cartilage structure at the top of the trachea that contains the vocal cords. The “voice box”or “Adam’s apple”.
Vocal Cords - consist of 2 elastic folds of tissue in larynx. As air passes through, they vibrate and produce sound.
Larynx and vocal cords

6. Bronchi: (plural) In the chest cavity, the trachea divides into 2 branches that enter each lung.
Left Bronchus
Right Bronchus

7. Lungs: Organs of respiration specialized for the exchange of gases between the blood and the atmosphere
Left Lung
Right Lung

8. Alveolus: Air sac at the end of a bronchiole where gas exchange occurs
Bronchiole: One of the finest branches of the bronchial tubes; ends in an air sac
Alveolus: Air sac at the end of a bronchiole where gas exchange occurs
Bronchioles and Alveoli

9. The Mechanics of Breathing
Inhalation
The diaphragm is a large, flat muscle located along the bottom of the rib cage. It separates the chest cavity from the abdominal cavity
During inhalation, the diaphragm contracts and moves down.
As the chest cavity expands in size, the volume increases and the pressure decreases relative to the atmosphere.
To equalize the pressure, air rushes into the lungs.
Inhalation is also called inspiration.

10. The Mechanics of Breathing
Exhalation
During exhalation, the diaphragm relaxes and moves up.
As the chest cavity decreases in size, the volume decreases and the pressure increases relative to the atmosphere.
To equalize the pressure, air rushes out of the lungs!
Exhalation is also called expiration.
Watch an animation!