Breathing and Cellular Respiration
The oxygen that arrives at the cells from the lungs is used by the cells to release the energy
stored in molecules of sugar.Cellular respirationis the process of breaking down glucose
to release energy (see theCell Functionschapter). The waste products of cellular respiration
include carbon dioxide and water. The carbon dioxide molecules move out of the cells and
into the capillaries that surround the cells. The carbon dioxide is removed from the body
by the lungs.
Lesson Summary
- Your respiratory system is made up of the tissues and organs that allow oxygen to enter
and carbon dioxide to leave your body. These structures include your nose, mouth,
larynx, pharynx, lungs, and diaphragm. The main function of the respiratory system is
to bring oxygen into the body and releases carbon dioxide into the atmosphere. During
inhalation, the diaphragm contracts and moved downward. The rib muscles contract
and cause the ribs to move outward, causing the chest volume to increase. Air pressure
inside the lungs is less than the air pressure outside so air is sucked into the lungs.
When the diaphragm and rib muscles relax, air is pushed out of the lungs. Exhalation
is normally a passive process. - Oxygen enters the lungs, passes through the alveoli and into the blood. The oxygen
is carried around the body in blood vessels. In a similar way, carbon dioxide, a waste
product, moves into the blood capillaries by passive diffusion and is brought to the
lungs in the pulmonary circulation. The carbon dioxide is released into the air during
exhalation. The oxygen that arrives from the lungs is used by the cells during cellular
respiration to release the energy stored in molecules of sugar. A waste product of
cellular respiration, carbon dioxide, is removed from the body by exhalation.
Review Questions
- Name the parts of the respiratory system.
- What is the main function of the respiratory system?
- A classmate says that the lung muscles cause the lungs to move during breathing. Do
you agree with your classmate? - How do the respiratory system and the cardiovascular system work together?
- Breathing is an involuntary action. Does this mean that you cannot control your
breathing? - In what part of the lung does gas exchange occur?
- What is the difference between breathing and respiration?
- Identify how breathing and cellular respiration are connected.
- What is the important gas that is carried into the lungs during inhalation?