Which of the following best describes the chloride shift as seen in the figure?
Respiration gas exchange
Once oxygen has diffused through the alveoli, it joins the bloodstream and is transferred to the tissues, where it is unloaded, while carbon dioxide diffuses out of the bloodstream and into the alveoli, where it is expelled from the body. Despite the fact that gas exchange is a continuous operation, oxygen and carbon dioxide are transported in separate ways.
Despite the fact that oxygen dissolves in blood, only a small amount is transferred this way. Just about a quarter of the oxygen in the blood is dissolved in the blood itself. The bulk of oxygen is bound to a protein called hemoglobin and brought to the tissues (98.5 percent).
Hemoglobin, or Hb, is a four-subunit protein present in red blood cells (erythrocytes) that consists of two alpha and two beta subunits (Figure 20.19). Each subunit is surrounded by an iron-containing central heme group that binds one oxygen molecule, allowing each hemoglobin molecule to bind four oxygen molecules. Molecules with more oxygen attached to the heme groups are more vibrantly colored. As a result, oxygenated arterial blood with four oxygen molecules in the Hb is bright red, while deoxygenated venous blood is darker red.
As biology – carbon dioxide transport in red blood cells (ocr
The mechanism of respiration, or gas exchange, is the other main operation in the lungs. The aim of respiration is to provide oxygen to body cells during cellular respiration and to remove carbon dioxide from the body, which is a waste product of cellular respiration. All gases must be transferred between the external and internal respiration sites in order for oxygen and carbon dioxide to be exchanged. Despite the fact that carbon dioxide is more soluble in blood than oxygen, all gases need a specialized transport system to transport the majority of gas molecules between the lungs and other tissues.
Despite the fact that oxygen is carried through the blood, it is not very soluble in liquids. While a small amount of oxygen dissolves in the blood and passes through the bloodstream, it only accounts for around 1.5 percent of the overall amount. A specialized transport system that depends on the erythrocyte—the red blood cell—transports the bulk of oxygen molecules from the lungs to the body’s tissues. Hemoglobin, a metalloprotein found in erythrocytes, is responsible for binding oxygen molecules to the erythrocyte (Figure 22.5.1). Heme is the iron-containing part of hemoglobin, and it is heme that binds oxygen. Since each hemoglobin molecule contains four iron-containing Heme molecules, each hemoglobin molecule can hold up to four molecules of oxygen. As oxygen diffuses from the alveolus to the capillary through the respiratory membrane, it also diffuses through the red blood cell and is bound by hemoglobin. The final product, oxyhemoglobin (Hb–O2), is formed when oxygen binds to hemoglobin, as seen in the following reversible chemical reaction. Oxyhemoglobin is a bright red-colored molecule that helps to give oxygenated blood its bright red color.
Sn1 reaction energy diagram
This chapter is particularly applicable to Section F8(ii) of the 2017 CICM Primary Syllabus, which requires exam candidates to “describe the carbon dioxide carriage in blood, including the chloride change.”
Westen and Prange (2003) provide a good description of the situation, but their article is locked behind a paywall. So is Klocke’s excellent paper from 1988, which goes over all of the steps in the chloride shift process in great detail. If you’re going to spend money on something, you may as well buy the official exam textbook. The original paper on “Anionenwanderungen in Serum und Blut” by Hartog Jacob Hamburger is sadly unavailable, but maybe this is for our own good.
There’s certainly something more official out there, but most writers have an explanation that’s so similar to the one above that repeating it all would be pointless. In short, if this ever comes up in a viva, as long as the words “chloride” and “erythrocytes” are included in the same sentence, you should already be halfway there. The following are the most critical points:
Assigning a 1h nmr spectrum
The Hamburger phenomenon (also known as the lineas phenomenon, after Hartog Jakob Hamburger) is a mechanism that occurs in the cardiovascular system and refers to the exchange of bicarbonate (HCO3) and chloride (Cl) through the membrane of red blood cells (RBCs).
Carbon-13 nmr spectroscopy
As a byproduct of normal metabolism, carbon dioxide (CO2) is released in tissues. It dissolves in blood plasma and enters red blood cells (RBC), where it is hydrated to carbonic acid by carbonic anhydrase (H2CO3). Carbonic acid then dissociates spontaneously into bicarbonate ions (HCO3) and a hydrogen ion (H+). More CO2 diffuses into the cell passively in response to a decrease in intracellular pCO2.
Charged ions (H+, HCO3) are usually impermeable to cell membranes, but RBCs can exchange bicarbonate for chloride using the anion exchanger protein Band 3. As a result of the increase in intracellular bicarbonate, bicarbonate export and chloride intake occur. This exchange is referred to as the “chloride transfer.” As a result, the concentration of chloride in systemic venous blood is lower than in systemic arterial blood: high venous pCO2 allows RBCs to emit bicarbonate, which then leaves the RBC in exchange for chloride entering. [two]