The Physiology Thread

[chbare]

Let us try something a little different and perhaps we can enhance our knowledge of physiology. It goes like this; you post a physiological process, somebody explains how that process works and then posts another process, the next person explains that process and posts another process of their own, etc.....

"The Chloride Shift"

Take care,

chbare.

[Just Plain Ruff]

sounds like a horror story or a suspense film.

[uglymedic]

An immature *sshole like me would probably say something like, "Sexual Intercourse"!

But I promise, I'm not going to!

ug

[pinymayu]

chloride shift

The movement of chloride ions from the plasma into red blood cells as a result of the transfer of carbon dioxide from tissues to the plasma, a process that serves to maintain blood pH.

[DwayneEMTP]

When carbon dioxide diffuses into the blood plasma and then into the red blood cells (erythrocytes) in the presence of the catalyst carbonic anhydrase most CO2 reacts with water in the erythrocytes and the following dynamic equilibrium is established

H2O + CO2 <-> H2CO3

Carbonic acid, H2CO3, dissociates to form hydrogen ions and hydrogencarbonate ions. This is also a reversible reaction and undissociated carbonic acid, hydrogen ions and hydrogencarbonate ions exist in dynamic equilibrium with one another

H2CO3 <-> H+ + HCO3-

Inside the erythrocytes negatively charged HCO3- ions diffuse from the cytoplasm to the plasma. This is balanced by diffusion of chloride ions, Cl-, in the opposite direction, maintaining the balance of negative and positive ions either side. This is called the 'chloride shift'.

The dissociation of carbonic acid increases the acidity of the blood (decreases its pH). Hydrogen ions, H+, then react with oxyhaemoglobin to release bound oxygen and reduce the acidity of the blood. This buffering action allows large quantities of carbonic acid to be carried in the blood without major changes in blood pH.

Hb.4O2 + H+ <-> HHb+ + 4O2

(Hb.4O2 is sometimes written HbO8.)

It is this reversible reaction that accounts for the Bohr effect. Carbon dioxide is a waste product of respiration and its concentration is high in the respiring cell and so it is here that haemoglobin releases oxygen.

Now the haemoglobin is strongly attracted to carbon dioxide molecules. Carbon dioxide is removed to reduce its concentration in the cell and is transported to the lungs were its concentration is lower. This process is continuous since the oxygen concentration is always higher than the carbon dioxide concentration in the lungs. The opposite is true in respiring cells.

Pretty cool thread chbare! Is it ok to cut and paste or do you want summaries?

(man I hate bio-chem)

"The Krebs Cycle"

Dwayne

[JakeEMTP]

Here is what I have been taught about the Krebs' Cycle.

I cut and pasted it out of pure convenience.

http://incolor.inebraska.com/mcanaday/Krebs%20Phases.htm

" Calcium and Potassium Channels "

[JPINFV]

Process by which the majority of NADH and FADH is produced for use during the electron transport chain, but also a single GTP is produced for use by the cell. Also known as The Citric Acid Cycle, the process is a cycle because of the regeneration of the first intermediate by the last step. The main input (besides NAD, FAD, and GDP which are required to produce the products) is Acetyl-Co-enzyme (CoA). CoA is produced from Pyruvate prior to the start of the Krebs Cycle (2 pyruvates are produced from Glucose in the first main process of metabolism called Glycolysis).

The krebs cycle occurs inside of the mitochondrial matrix (The space surrounded by the inner-membrane) of the mitochondria in eukaryotes. In prokaryotes, the Krebs Cycle occurs inside the cytoplasm.

The classical model for the complement system.

[chbare]

Cut and paste away everybody as long at it explains the process, this is all about learning.

Take care,

chbare.