Download External and Internal Respirations The process by which Oxygen

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External and Internal Respirations
The process by which Oxygen and Carbon dioxide diffuse in and out of the blood is
respiration. Respiration occurs in two areas of the body and is also referred to as gas exchange.
The gas exchange across the respiratory membrane in the lungs is known as External respiration
while gas exchange across the respiratory membrane in the metabolizing tissues is known as the
Internal respiration. In external respiration, the exchange of gases takes place between the alveoli
and lung capillaries. Oxygen is distributed into the blood from the alveoli and Carbon dioxide
moves from the blood in the alveoli. While in internal respiration the exchange of gases is only
in body tissues.
Gas exchange in the lungs is called as external respiration as the alveolar air is outside of
the body. As blood flows through the pulmonary capillaries, Oxygen diffuses into the blood and
Carbon dioxide diffuses into the alveolar gas. Both the gases diffuse down their own partial
pressure gradient and equilibrate. Oxygen -rich blood will then be delivered to the tissues. The
gases move in opposite directions in internal respiration compared to external respiration.
Oxygen is diffused out of the blood into the tissues and Carbon dioxide is diffused out of the
tissues into the blood. In external respiration, air is drawn into the body to supply Oxygen to the
lungs and air is expelled from the lungs to remove Carbon dioxide from the body. In internal
respiration, the gases in the air which is already inhaled in the lungs by external respiration are
exchanged with gases in the tissues. As a result of internal respiration, Carbon dioxide is
removed from the blood and is replaced with Oxygen.
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Reference
External and Internal Respiration in the Lungs: Definition & Process. In Education Portal.
Retrieved on March 27, 2014 from http://education-portal.com/academy/lesson/externaland-internal-respiration-in-the-lungs-definition-process.html#lesson