The Respiratory
System
Chapter 2 Section 4
Function
• The purpose of respiration:
o To bring in and use oxygen
o To release carbon dioxide and water
• There are 2 parts to respiration:
o Breathing (inhale and exhale)
o Cellular Respiration- cells release energy from
food
Breathing
• INHALE: The diaphragm, which is a muscle
under the lungs, contracts to pull air into the
lungs.
• EXHALE: The diaphragm relaxes and the
lungs recoil to push air out of the lungs.
• Rib muscles also contract to lift the ribs,
making more room for air to enter.
Cellular Respiration
C6H12O6 + O2 = CO2 + H2O + ATP
• Oxygen is used by cells to release energy
from glucose (sugar).
• O2 enters the lungs and passes into the
blood to be delivered to cells.
• CO2 leaves blood and goes into lungs to be
exhaled.
Structure
• Nose- main passageway in and out of
respiratory system
• Pharynx- the throat. Used by both food
and air so it branches into 2 paths: the
esophagus (food) and the larynx (air)
• Larynx- part of throat containing vocal
chords to make sound when vibrated by
air.
Structure cont.
• Trachea- large tube serves as a
passageway for air, aka windpipe.
• Bronchus (Bronchi)- two branches
at end of trachea to go to the left
and right lungs.
• Bronchioles- smaller and smaller
branches of the bronchi
• Alveoli- tiny air sacs at the ends of
the bronchioles where air is
exchanged with blood in the
capillaries.
Diagrams