A. Why the Body Needs Oxygen *Oxygen, glucose Ch. 14 section 3 Respiratory System A. Why the Body Needs Oxygen *Oxygen, glucose *energy-releasing chemical reactions 1. Breathing vs. Respiration -Oxygen + glucose undergo a chemical reaction inside cells -release energy -produces CO2 and water -refers to the movement of air into and out of the lungs

C6H12O6 + 6O2 6CO2 + 6H2O + energy 2. 3 Organ Systems work together a. respiratory system: get O2 into your lungs b. circulatory system: carries O2 + glucose to the body c. digestive system: absorbs glucose from food O C6H12O6 + 6O2 6CO2 + 6H2O + energy

most of the air goes back into the atmosphere. B. The Air You Breathe 1. Air is made up of: a. 21% O2 b. 78% N2 c. 1% CO2 2. When we breathe, most of the air goes back into the atmosphere.

1. Air also includes particles -dust, plant pollen, ashe from fires, C. The Path of Air 1. Air also includes particles -dust, plant pollen, ashe from fires, and microorganisms 2. Nose 2. Nose: a. lining of the nose contain blood vessels b. warm blood heats the air c. cells lining the nose produce mucus d. cilia: hairlike extensions -sweep mucus that has trapped particles and bacteria into the stomach -or you sneeze it out

3. The Pharynx: a. share it with digestive system b. epiglottis: keeps food from entering the lungs

4. The Trachea: a. windpipe b. made of rings of cartilage c. lined with cilia and mucus -sweep the mucus to swallow

5. The Bronchi and Lungs: a. air moves from trachea to the bronchi -directs air into the lungs b. lungs: the main organs of resp. c. alveoli: at the end of the each bronchi -tiny sacs of lung tissue -movement of gases between air and blood -surrounded by capillaries