<< Chapter < Page Chapter >> Page >
CO 2  + H 2 O H 2 CO 3 (carbonic acid)   HCO 3  + H + (bicarbonate)  

The benefit of the bicarbonate buffer system is that carbon dioxide is “soaked up” into the blood with little change to the pH of the system. This is important because it takes only a small change in the overall pH of the body for severe injury or death to result. The presence of this bicarbonate buffer system also allows for people to travel and live at high altitudes: When the partial pressure of oxygen and carbon dioxide change at high altitudes, the bicarbonate buffer system adjusts to regulate carbon dioxide while maintaining the correct pH in the body.

Carbon monoxide poisoning

While carbon dioxide can readily associate and dissociate from hemoglobin, other molecules such as carbon monoxide (CO) cannot. Carbon monoxide has a greater affinity for hemoglobin than oxygen. Therefore, when carbon monoxide is present, it binds to hemoglobin preferentially over oxygen. As a result, oxygen cannot bind to hemoglobin, so very little oxygen is transported through the body ( [link] ). Carbon monoxide is a colorless, odorless gas and is therefore difficult to detect. It is produced by gas-powered vehicles and tools. Carbon monoxide can cause headaches, confusion, and nausea; long-term exposure can cause brain damage or death. Administering 100 percent (pure) oxygen is the usual treatment for carbon monoxide poisoning. Administration of pure oxygen speeds up the separation of carbon monoxide from hemoglobin.

 Percent oxygen saturation of hemoglobin at an oxygen pressure of 100 millimeters of mercury decreases as percent carbon monoxide increases. In the absence of carbon monoxide, hemoglobin is 98 percent saturated with oxygen. At twenty percent carbon monoxide, hemoglobin is 77 percent  saturated with oxygen.  At forty percent carbon monoxide, hemoglobin is 68 percent saturated with oxygen. At sixty percent carbon monoxide, hemoglobin is 40 percent saturated with oxygen. At eighty percent carbon monoxide, hemoglobin is 20 percent saturated with oxygen.
As percent CO increases, the oxygen saturation of hemoglobin decreases.

Section summary

Hemoglobin is a protein found in red blood cells that is comprised of two alpha and two beta subunits that surround an iron-containing heme group. Oxygen readily binds this heme group. The ability of oxygen to bind increases as more oxygen molecules are bound to heme. Disease states and altered conditions in the body can affect the binding ability of oxygen, and increase or decrease its ability to dissociate from hemoglobin.

Carbon dioxide can be transported through the blood via three methods. It is dissolved directly in the blood, bound to plasma proteins or hemoglobin, or converted into bicarbonate. The majority of carbon dioxide is transported as part of the bicarbonate system. Carbon dioxide diffuses into red blood cells. Inside, carbonic anhydrase converts carbon dioxide into carbonic acid (H 2 CO 3 ), which is subsequently hydrolyzed into bicarbonate (HCO 3 ) and H + . The H + ion binds to hemoglobin in red blood cells, and bicarbonate is transported out of the red blood cells in exchange for a chloride ion. This is called the chloride shift. Bicarbonate leaves the red blood cells and enters the blood plasma. In the lungs, bicarbonate is transported back into the red blood cells in exchange for chloride. The H + dissociates from hemoglobin and combines with bicarbonate to form carbonic acid with the help of carbonic anhydrase, which further catalyzes the reaction to convert carbonic acid back into carbon dioxide and water. The carbon dioxide is then expelled from the lungs.

Art connections

[link] The kidneys are responsible for removing excess H+ ions from the blood. If the kidneys fail, what would happen to blood pH and to hemoglobin affinity for oxygen?

[link] The blood pH will drop and hemoglobin affinity for oxygen will decrease.

Got questions? Get instant answers now!

Questions & Answers

what is genetic
Nad Reply
what is écosystème
what is écosystème
what is écosystème
what is écosystème
discuss adaptations of flight in birds
Cassim Reply
what is an enzymes
Joseph Reply
mention two types of metabolic
what is a cell?
is the biological catalyst that speed up chemical reaction in the living thing
an enzymes is a biological catalyst that speed up a chemical reaction in living organisms and it is protein in nature
enzymes are protein that act as biological catalysts
what agglutriation
enzymes are biological catalysts that speed up the chemical reactions in a living organism
what is photosynthesis
Conast Reply
photosynthesis is the process by which green plants manufacture their own food from water and carbon dioxide using sunlight as a source of their energy releasing oxygen as a by-product.
what is the function of thé utérus
what are runners
Godfrey Reply
what is an environment
Bwambale Reply
diagrams are not indicated, why?
Simon Reply
diagrams for what?
A vaccination is a treatment which makes the body stronger against an infection. The body fights infections using the immune system, which is made up of millions upon millions of cells including T cells and B cells.
define the term immunity
can simply defined as an exemption from an attack
is the ability of an organism to resist a particular infection or toxin by a specific antibodies or sensitized white blood cells
difference between cell and cell membrane
Sunday Reply
cell is a basic unit of living body however cell membrane is a protective layer of cell.
very good
which topic would you like to discuss today?
what do you understand by the term vaccine?
guy I need the answer of this question what occurs during photosynthesis
REAL Reply
Photosynthesis is the process that plants use to convert light into food. During this process, plants create carbohydrates starting with only carbon dioxide and water. Sunlight provides the energy that makes photosynthesis possible.
@Stanley,that's how I could as well put it
what are different between genotype and phenotype
Martha Reply
what is light microscope and electronic microscope
what occurs during photosynthesis
what are importance of biology
what is the meaning of computer science
genotype is the genetical constitution of the gene
what is ecology
Adeyemo Reply
what is zoology
zoology branch of biology that study animals
a branch of biology which deals with the study of animals
A plant is a living thing that grows in the earth and has a stem, leaves, and roots
Bello Reply
what is a plant
dalitso Reply
A plant is a living thing that grows in the earth and has a stem, leaves, and roots
a plant is an is a living thing that is classified under autothrops because it makes its own food through the process of photosynthesis .
a plant is also known as autotropic category and a plant have root & stem
what is plant
Odion Reply
Plants are autotrophic
Then animal are heterotrophic
what are organisms
Godfred Reply
Living structures
living and non living which charectrised by different properties
organisms living and nonliving components of the environment with distinct xtics

Get the best Biology course in your pocket!

Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Biology' conversation and receive update notifications?