Final answer:
A decrease in external respiration would likely affect internal respiration by reducing the amount of oxygen that is transferred to the blood and increasing carbon dioxide levels, which in turn would lead to impaired oxygen delivery to tissues and decreased efficiency in removing carbon dioxide during internal respiration.
Step-by-step explanation:
If a pathology caused a decrease in external respiration, internal respiration would likely be affected as well. External respiration refers to the gas exchange process between the alveoli in the lungs and the blood in the pulmonary capillaries, where oxygen is taken up by the blood and carbon dioxide is released. If external respiration is compromised, the oxygen content in the blood can decrease, and carbon dioxide levels may increase, which negatively impacts oxygen delivery to tissues and the removal of carbon dioxide from them during internal respiration.
For example, if there is increased resistance in the airways due to conditions like asthma or an allergic reaction causing airway swelling, this leads to a decrease in the airflow to the alveoli, resulting in less oxygen entering the blood and more carbon dioxide remaining. This could lead to a state called V/Q mismatch, where ventilation (V) and perfusion (Q) may not be adequately matched, thereby impairing gas exchange.
When internal respiration is compromised, tissues struggle to receive enough oxygen for cellular metabolism and the removal of metabolic waste decreases in efficiency.