Huff Puff
The respiratory system is a collection of organs whose primary function is to take in oxygen and expel carbon dioxide. These organs include the diaphragm, the lungs, the nose, the mouth, the pharynx, the larynx, the epiglottis, the trachea, the bronchus, bronchiole, and the alveoli. There is also breathing respiration and cellular respiration.
The lungs and the diaphragm are the two biggest parts of the respiratory system. The diaphragm is the muscle that helps you breathe. Breathing is how we get oxygen to our lungs, this is done by your diaphragm pulling on your lungs, sucking air in. Or in the more scientific way: it creates more volume in the chest, the air pressure in the lunch is lowered and air rushes into your lungs.
Respiration is how the oxygen gets to your body, through your blood. Cellular respiration is really cool, oxygen is getting used at a cellular level. The oxygen gets turned into sugar or another source of energy.
The ability to change your breathing in the ability of the blood transport from our lungs to cells in critical organs in acclimatization. Respiration will speed up at higher altitudes. Bone marrow makes more RBC's with more hemoglobin (see circulatory system)

The pharynx and the larynx are important organs in the respiratory system as well. The pharynx is the passage from the mouth to the larynx and esophagus. The larynx is the area of the throat that contains the vocal cords, and produce vocal sounds. There are two bands that stretch across it, when air hits them, the vibrate and make a sound.
The trachea and bronchus are the next two tubes in this system. The trachea is the tube that connects to larynx to the bronchus, and furthermore to the lungs. The bronchus connects to the trachea, and to the lungs.
The bronchiole and the alveoli are the last part, other than the capillaries that connect to them. When the air comes from the bronchus' it flows into the bronchiole. Then from the bronchiole, air fills the alveoli and gets sucked into the capillaries just one cell away, to be transported to the heart. The carbon dioxide gets traded for the oxygen and gets breathed out.
When we exhale, there are two things that come. Water vapor, and carbon dioxide, as well as heat. While the blood is transporting blood around the body, it also picks up heat found in your body. You can feel this by putting your hand in front of your mouth as you breathe.
