1. 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

2. 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 + 6O CO2 + 6H2O + energy

3. 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.

4. 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

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

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

11. 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