RESPIRATORY SYSTEM
The Respiratory System is the group of organs that takes oxygen from the air and removes carbon dioxide from the body.
About 20% (1/5) of the air we breathe is made up of oxygen.
Parts of the Respiratory System and their functions
1) nose - air enters the body through the nose
a) The nose prepares the air for the lungs. It warms,
moistens, and cleans the air.
b) mucus - a thick, sticky fluid produced by the lining of the nose. Mucus traps dust and germs to clean the air.
c) cilia - tiny hairs in the nose
2) pharynx - area behind the nose that leads to the throat
3) larynx - voice box
a) epiglottis - a small flap that covers the larynx when
we swallow and opens it when we breathe
4) trachea - windpipe; tube that carries air to the lungs
5) bronchi - The trachea divides into 2 tubes called
bronchi that go to the lungs

6) bronchioles - In the lungs, the bronchi branch into
smaller and smaller tubes called bronchioles.
7) alveoli - air sacs; this is where the exchange of gases
takes place (oxygen and carbon dioxide are exchanged
a) tiny blood vessels called capillaries surround each
air sac inhale - to breathe in exhale -to breath out
We inhale oxygen rich air and exhale carbon dioxide.
Muscles that help your lungs work
1) muscles between the ribs
2) diaphragm - the large dome-shaped muscle below
the lungs
When you inhale, the muscles between the ribs contract
(tighten) pulling the ribs up and out. The diaphragm also contracts (it flattens) and moves down. These 2 things make room for the lungs to expand (get larger) and fill with air.
When you exhale, the muscles between the ribs relax and your ribs move back. The diaphragm also relaxes and goes back to its normal position and shape. These 2 things push air out of the lungs.
The lungs have NO muscles.

Blood
A - Parts of the blood
1) white blood cells - fight infection
2) red blood cells - carry oxygen
a - when red blood cells carry oxygen, they are
bright red
b - after they give up oxygen, they are purplish
3) plasma - the watery part of the blood
4) platelets - clot the blood to stop bleeding
B - Functions of the blood (as it relates to the respiratory system)
1) - to carry oxygen to all body cells
2) - to carry nutrients to body cells
3) - to carry wastes from body cells to the organs that
excrete (get rid of) them
Our body cells use oxygen to break down simple sugar, which is a nutrient, into energy.
sugar + oxygen ----------- carbon dioxide + water + energy
Wastes produced by our body cells as they do their jobs:
1) carbon dioxide
2) water
3) nitrogen - released by body cells when they break down protein
4) salts
All activities use energy.