1. Human Organ Systems
The Respiratory System

2. Function The respiratory systems main job is gas exchange.
The respiratory system supplies your body with oxygen needed for respiration.
The respiratory system also works to remove CO2 gas.

3. Function cont.
Your respiratory works with other organ systems to help you maintain homeostasis.
Digestive and Circulatory: Respiratory system works with these two systems to provide the raw materials for cellular respiration.
Excretory system: The respiratory system aids in the removal of metabolic wastes: CO2 and H2O

4. Components
Nose: Nose is the primary entry and exit site of gases in the body. Mucous and Cilia (fine hairs) help to moisten and filter the air you breath.
The air is also warmed as it passes through your nasal passageways.
Mouth: Secondary entry and exit site for gases. Important especially during physical exertion when the body needs more O2 and is producing more CO2.

5. Pharynx, Larynx and Trachea
Once the air leaves your nose or mouth, it next travels into your Pharynx (Throat).
The air then travels past a protective flap on tissue called the epiglottis, and the air passes through your larynx (Voicebox)
Next the air passes into your trachea (windpipe)
The trachea carries the air into your lungs.

6. Lungs
Another important component of the respiratory system are the lungs.
The lungs are lobed air sacs that are found in the thoracic cavity.
The right lung has 3 lobes, the left lung has 2.
They are surround by a thin membrane called the Pleura.

7. Air vessels
You trachea splits off into two large air tubes called the left and right Bronchi.
The bronchi branch off to form smaller tubules called bronchioles
The bronchioles get even smaller and end up in small grapelike bundles called alveoli.
It is at the alveoli that gas exchange occurs.

8. A two-way street
Unlike your digestive system, your respiratory system only one point of entry and exit.
Air flows into your body is this order.
Nose or mouth  Pharynx  Larynx  Trachea  left or right bronchi  bronchioles  Alveoli.
Air leaves your body through the same structures just in reverse order.

9. Air pressure
The air flows into and out of your lungs due to differences in air pressure inside and outside your lungs.
Every breath you take has two components, an inhalation, and an exhalation.
Inhalation requires energy while exhalation does not.

10. “I never inhaled” –B. Clinton
When you inhale, a large muscle located at the bottom of your lungs called the diaphragm contracts.
When the diaphragm contracts, it pulls downward on your lungs, causing them to increase in volume.
As volume is increased, the air pressure inside you lungs decreases.
The air moves from high pressure (outside) to low pressure (inside)

11. Waiting to exhale
When you relax your diaphragm it allows the lungs to go back to their relaxed state.
The lungs lose volume which causes the air pressure to increase.
This increase in air pressure causes the air in your lungs to be forced out of your body.

12. Breathing summary
Inhalation: Volume of lungs increases, air pressure decreases, air flows in.
Exhalation: Volume of lungs decreases, air pressure increases, air flows out.
Also aiding in this process are muscles between your ribs called intercoastals.
The intercoastals help increase the volume of your lungs by expanding the rib cage during inhalation.

13. Video
Lets watch a short video that will give us a good look at what happens everytime we breathe in, and breathe out.
Respiratory system video