Adjustment to Metabolic Needs of Tissues

Adjustment to Metabolic Needs of Tissues - Metabolically...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Adjustment to Metabolic Needs of Tissues Oxygen Unloading Metabolically active tissues consume oxygen to replace the energy used to do work. So metabolically active tissues have a lower P O2 than non-working tissues. At this lower P O2 , more oxygen will be unloaded from Hb. Using Figure 6 , at a P O2 of 20 mmHg, Hb is only 25% saturated (it has released 2 additional oxygen molecules to replenish the oxygen used by these tissues). Metabolically active tissues have increased temperatures and higher P CO2 levels -- at these higher temperatures and higher acidity , Hb will unload O 2 more readily (the curve shifts to the right) (see Figure 7 ). Other factors may increase oxygen unloading from Hb. The metabolite bisphosphoglycerate , which can be increased during fever and in response to hormonal activation, binds to Hb and causes HbO 2 to release O 2 . Figure 7 Carbon Dioxide loading
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Metabolically active tissues also affect how the blood carries CO 2 . A small portion of total CO 2 will dissolve directly in the plasma of the blood. About 20 - 25% of the CO 2 carried by the blood will bind to Hb. Low levels of HbO 2 (during activity) enables the Hb to transport more CO 2 , known as the Haldane effect. HbO 2 does not bind to CO 2 as well as deoxyhemoglobin ; so the more O 2 that is unloaded from Hb, the more CO 2 can be bound to Hb. Furthermore, HHb binds more H + than HbO 2 which shifts the CO 2 + H 2 O --> H 2 CO 3--> HCO 3-+ H + reaction to the right enabling an increased conversion of CO 2 into carbonic acid and bicarbonate. The majority of CO 2 produced by the body will be converted into HCO 3-and dissolve in the plasma. This conversion changes the pH of the blood and can alter the respiratory rate....
View Full Document

This note was uploaded on 01/30/2012 for the course BSC BSC1085 taught by Professor Sharonsimpson during the Fall '10 term at Broward College.

Ask a homework question - tutors are online