What is the role of partial pressure in external and internal respiration?

Question

What is the role of partial pressure in external and internal respiration?

Answer 1

Respiration -- exchange of gases between organism and the environment

- internal respiration:  occurs in mitochondria; use of cellular fuels (glucose, fatty acids) to produce ATP; O2 is final electron acceptor and CO2 produced as a metabolic waste product.  

- external respiration:  oxygen from the environment taken up and delivered to individual cells; carbon dioxide produced during cell metabolism excreted into environment

Answer 2

When we are talking of external respiration the partial pressure is very important as it is responsible for making oxygenated   blood in our lungs because the  air we breathe at this time has higher partial pressure which  leads to dissolution of oxygen in our lungs blood. When this blood is transported to various organs its partial pressure decreases as a result of which the dissolved oxygen releases to used by various cells of the organs where internal respiration takes place therefore it would not be wrong to say that partial pressure plays a significant role in both external as well as internal respiration.

This could be better understood if you consider a bottle of your favourite carbonated drink, when the bottle is closed the CO2 remained diossolved in the drink but when it is opened the gas bubbles out as partial pressure decreases.

Answer 3

The external role is the exchange of gases in the lungs, that takes place between alveolar air and venous blood flowing through lung capillaries. The internal role is the exchange of gases in the tissues, in which takes place between the arterial blood flowing through tissue capillaries and cells.