Download Respiratory System

Breathing
• Breathing- (aka ventilation), The process
through which the respiratory system moves air
into and out of the lungs.
• In contrast, Respiration refers to cellular
respiration, a complex metabolic activity during
which the energy needed to support life activities
is released.
• During respiration, the body uses Oxygen to
break the bonds of a sugar molecule. The waste
products of respiration are carbon dioxide and
water.
• Both the respiratory and the circulatory
systems are needed to support respiration
• During inhalation, the diaphragm, a broad,
thin muscle separating the chest cavity
from the abdomen, contracts and moves
downward. This increases the size of the
chest cavity.
• The intercostal, or rib, muscles also
contract and cause the ribs to move
upward and outward.
• During exhalation, the diaphragm and the
intercostal muscles relax, the volume of
the chest cavity decreases, and internal air
pressure increases. This forces air out of
the lungs.
• Oxygen and Carbon Dioxide are
exchanged between the lungs and the
bloodstream by diffusion.
• Oxygen is moved into the lungs during
inhalation and carbon dioxide and water
are removed during exhalation.
• The actual exchange of these gases in the lungs
takes place in clusters of alveoli, or grape-like
clusters of air sacs.
• The lungs are snugly enclosed by the
pleura, a double-layered membrane.
• Between the two layers is a narrow space
called the pleural cavity, which is filled with
pleural fluid.
• This fluid helps the lungs glide easily
against the chest wall during breathing.