1. What it Means to Breathe

2. Breathing
When we breathe, we are moving gases from the atmosphere into and out of our lungs Ex. Oxygen, Nitrogen, CO2
Made up of Two Processes:
Ventilation
Respiration

3. Ventilation
Movement of air from the nasal passages down to the alveoli
Occurs because of movement of the diaphragm changes the pressure in the lungs
Exhale (Expiration) = Relaxing
Inhale (Inspiration) = Contraction

4. Diaphragm Contraction Causes Volume Changes in the Lungs
Medulla Oblongata in the brain sends signals to the diaphragm to contract
When it contracts it flattens out and creates more room in the chest cavity, so air gets drawn in due to decreased pressure

5. Breath Rate Breathing rate depends on the level of CO2 in our blood
Increased CO2 = increased breath rate
Resting breath rate is between 12 and 20 breaths per minute

6. Lung Capacity
The amount of air that the lungs can hold varies with body size and weight
Total Lung Capacity (TLC) ~ 6,000mL
Tidal Volume (TV) is the amount of air usually inhaled ~500mL
More air can be inhaled or exhaled if forced

7. Respiration Also known as gas exchange
Oxygen is added to the blood and carbon dioxide is removed
In the lungs it is called external respiration
In the rest of your body it is called internal respiration

8. Gas Exchange Occurs Because of Diffusion

9. Oxygen and CO2 Transport
Once in the blood, O2 attaches to a molecule called hemoglobin for transport, while CO2 combines with water to form bicarbonate ions, which float in the plasma