1. Respiratory System
Mr. Lockhart

2. Functions of the Respiratory System
Gather oxygen for the body’s cells to use as energy
Remove CO2 (Carbon dioxide) from the body.
Functions of the Respiratory System

3. Gathering oxygen for the body’s cells
The body requires oxygen to carry out cellular respiration within its cells.
Cellular respiration is done by mitochondria and provides our bodies with nearly all the energy they use!
The respiratory system is responsible for pulling oxygen out of the air we breathe so the circulatory system can pick it up and transport it to all cells in your body.
Gathering oxygen for the body’s cells

4. Cellular respiration and other cellular processes produce a gas called carbon dioxide.
Carbon dioxide collects in the blood, and if not removed, can make the blood more acidic (very bad, we call this acidosis)
The blood transports the excess CO2 to the lungs where it can be exhaled back into the air.
Removing CO2

5. The nose Air is meant to be taken in through the nasal cavity.
The nasal cavity contains many hairs and a lot of mucus to catch particulates (small pieces) of dust/germs/anything that isn’t air so that you don’t breathe these into your body.
The nose

6. The pharynx is the space where the nasal cavity and the oral cavity merge. Both food and air pass through the pharynx.
When you swallow, a thin flap of tissue called the epiglottis covers the trachea, preventing you from choking and making sure the food heads down the esophagus instead.
The pharynx

7. The trachea is the only passageway for air to get to the lungs, and it is lined with lots and lots of mucus to catch any bacteria, viruses, food, or dust particles.
Additionally, the trachea is lined with cilia or hair-like extensions that catch particles. When the cilia are irritated (by dust or other particles) you will cough or sneeze the irritants back into the air.
Trachea

8. The Lungs and the Bronchi
At the end of the trachea, air enters the lungs. These are the main organs of the respiratory system. The lungs are filled with passages called Bronchi.
The Bronchi are the “branches” within the lungs that air travels through on its way to the alveoli.
The Lungs and the Bronchi

9. Alveoli The Alveoli are where oxygen is transferred into the blood.
An alveolus is very thin. So thin that gasses in the lungs can move through their walls and into the blood.
Likewise, gasses in the blood can move through the alveolar walls into the lungs.
Alveoli

10. Interactions with the musculoskeletal system
The diaphragm is a member of the musculoskeletal system that is responsible for your ability to breathe. The diaphragm is attached the to bottom of the lungs.
When you want to breathe in, the diaphragm pulls down on the lungs and the intercostal muscles (muscles between your ribs) move outward. This decreases the pressure on your lungs in your chest cavity and they fill up with air to replace the lost pressure.
When the diaphragm and intercostal muscles relax, your lungs are compressed and the air is pushed out.
Occasionally, your diaphragm will contract randomly. This causes hiccoughs.
Interactions with the musculoskeletal system

11. Interactions with the circulatory system
The air you breathe in is roughly 21% oxygen. (Other gases include Nitrogen and Carbon dioxide. Air is mostly nitrogen gas.)
The air you breathe out is about 16% oxygen.
The 5% difference is the oxygen that’s taken into your body and put into the circulatory system through the alveoli.
Additionally, the circulatory drops off excess CO2 into the lungs to be exhaled.
Interactions with the circulatory system