Carbon Dioxide Transport Flashcards
As blood is delivered to tissue, what prompted O2 molecule to “hop off” of a heme?
As the flow of CO2 entering the RBC as it shifts from the area of higher concentration in the tissue to an area of lower concentration in the blood; as the CO2 combines with water and then dissociates into H+ and HCO3-, the H+ migrate towards the heme groups in the Hgb molecules, changing shape of the molecule in the process, which forces O2 molecules off of the hemes allowing the H+ to hop on
How does CO2 get from the tissue into the RBC and what happens to it along the way?
It moves from the tissues into the interstitial space and then across the capillary membrane into the plasma, where a very small amount is dissolved, and a small amounts combine with proteins in the plasma
What is the CO2 that combines with the plasma called?
Carbamino compounds
What happens as soon as CO2 enters the RBC?
Most combine with water to form carbonic acid : CO2 + H2O = H2CO3
This reaction is called hydrolysis
What makes hydrolysis reaction happen really fast?
Enzyme known as carbonic anhydrase
What happens as soon as carbonic acid (H2CO3) is formed? Why?
Because H2CO3 (carbonic acid() is very unstable, it disassociates into H+ and HCO3- with the help of carbonic anhydrase
What is the major benefit of this breakdown of carbonic acid into hydrogen ions and bicarbonate so quickly?
It makes room for more CO2 to enter the RBC
What happens to the very small amounts of CO2 that make it into the RBC but doesn’t combine with water?
Some combine with proteins chains of Hgb to form carbamino hemoglobin. Some dissolve in RBC
What are the ways CO2 is transported in the blood from, the tissues back to the lungs?
- Dissolved in solution (RBC)
- Combines with water as carbonic acid (H2CO3) which dissociates into:
* HCO3- ions that shift into plasma (MOST SIGNIFICANT, MAJORITY)
* H+ combines with Hgb = deoxyhemoglobin (HHb) - Bounds to proteins (plasma = carbamino compounds) (and caraminohemoglobin)
What are the various forms of carbon dioxide transported to the tissues?
1) dissolved in plasma (5-10%)
2) combined with plasma proteins (carbamino compounds) (10-20%)
3) in the form of HCO3- (70-80%)
4) binds with protein chains on the Hgb molecules to form carbamino compound (carbaminohemoglobin)
5) H+ + Hgb = HHb (deoxyhemoblogin)
6) dissolved in RBC
7) carbonic acid
8) carbon monoxide
How did CO2 accumulate in the tissue?
Cellular metabolism
What determines how much CO2 has accumulated in the tissue?
The rate of cellular metabolism. Can be affected by many things
What determines how much oxygen is transported/ gets delivered to tissues?
Oxygen content of arterial blood (CaO2) and perfusion (Q) and cardiac output (CO)
