SEC S20W2 || Hemoglobin - Module 2

Hello Steemit community! As a medical student deeply immersed in the study of hematology, I’m excited to share my insights from this week’s module on hemoglobin and hematocrit.

Hello Steemit community! As a medical student deeply immersed in the study of hematology, I’m excited to share my insights from this week’s module on hemoglobin and hematocrit.

Hematology has always been a tough subject for people to grasp, but it is one of the most interesting modules. I still vividly remember how difficult it was for many students in my first year to understand the heme module, especially the biochemistry part because of hemoglobin and its related disorders. The hematology module is very closely associated with immunology (its definition) and oncology (its definition), and their pathophysiology is both complicated and interesting.

We all know oxygen is vital for human survival, but have you ever thought about why oxygen is so essential, and how it gets to every part of the body? Well, let me explain! The human body is made up of billions and trillions of cells, and each one needs oxygen to stay alive and function properly. Humans are eukaryotic organisms, and under normal conditions, our cells undergo aerobic respiration, which requires oxygen. But how does this oxygen reach every single cell in the body? How is it possible that even in different physical conditions, like high altitudes or areas with low oxygen pressure, our body still gets the oxygen it needs? The answer lies in hemoglobin—our body’s superhero!

Rafael Rangel, often considered the father of Venezuelan microbiology, played a key role in the development of bioanalysis and parasitology. His research on tropical diseases like yellow fever, hookworm, and leprosy was a breakthrough that set the stage for future medical advances in Venezuela. Unfortunately, Rangel's life ended tragically, when he took his own life by injecting Drabkin’s reagent, a chemical used in labs to measure hemoglobin levels. This tragedy serves as a harsh reminder of the emotional struggles faced by scientists and the harsh consequences of lack of recognition and resources.

Mechanism of Death:

Drabkin's reagent includes potassium ferricyanide and potassium cyanide. When anticoagulated blood is exposed to this reagent, hemoglobin gets released and turns into methemoglobin for colorimetric analysis. Potassium cyanide, a powerful neurotoxin, blocks cytochrome c oxidase in the mitochondria, causing cellular hypoxia and eventually death. This heartbreaking event reminds us that behind all scientific progress are real human challenges and emotions.

Hemoglobin is a crucial protein found inside erythrocytes (red blood cells) composed of globin chains and the heme group. The heme part consists of protoporphyrin and iron, while the globin part is made up of four polypeptide chains—two alpha chains and two beta chains—with a heme group in the center containing a ferrous iron atom capable of binding oxygen molecules.
Functions of Hemoglobin:

1. Oxygen Transport: Hemoglobin carries oxygen from the lungs to peripheral tissues, releasing it based on tissue demands. Hemoglobin loves to release oxygen in acidic environments (low pH), ensuring that tissues with higher activity (and acidity) receive more oxygen.

2. Carbon Dioxide Transport: Hemoglobin also helps transport carbon dioxide from tissues to the lungs for exhalation. Remember, carbon dioxide binds to the globin part of hemoglobin, not the heme part, making it different from oxygen binding.

3. pH Regulation:
Hemoglobin plays a key role in maintaining blood pH and hematocrit regulation. It binds hydrogen ions in acidic conditions and releases them in basic conditions, helping stabilize the blood’s pH balance.

There are several types of hemoglobin, some physiological and some pathological:

1. Hemoglobin A (HbA):The most common type in adults, consisting of two alpha and two beta chains.

2. Hemoglobin A2 (HbA2): Contains two alpha and two delta chains, found in small quantities in adult blood.

3. Hemoglobin F (HbF): Found abundantly in fetuses, this type has a higher oxygen-binding affinity than adult hemoglobin, helping the fetus compete for oxygen from the mother’s hemoglobin.

Pathological types include HbS (sickle cell hemoglobin), HbC, and HbSC, seen in conditions like sickle cell disease where abnormal hemoglobin can block blood vessels and cause severe symptoms.

As mentioned earlier, hematocrit measures the proportion of blood volume made up of red blood cells. It can be measured manually or via automated methods:

In modern clinical practice, automated hematocrit measurement is the gold standard due to its speed and precision. Automated systems not only provide hematocrit levels but also offer a comprehensive breakdown of RBC indices such as MCV (mean corpuscular volume) and MCH (mean corpuscular hemoglobin), aiding in the diagnosis of conditions like anemia and polycythemia.

However, manual hematocrit measurement, though less commonly used in daily clinical practice, remains an essential skill taught to medical students and laboratory technicians. It provides foundational knowledge of laboratory techniques and offers an alternative method in settings where automated analyzers are unavailable.

While automation dominates clinical practice, understanding both techniques equips healthcare professionals with the versatility needed for diverse medical settings.

1. Altitude Sickness in Mountaineers:

At high altitudes, the body compensates for lower oxygen levels by increasing red blood cells, thus raising hematocrit. This adaptation improves oxygen delivery but can lead to altitude sickness or, in extreme cases, chronic mountain sickness due to increased blood viscosity.

1. Blood Doping in Athletes:

Some athletes misuse hematocrit manipulation through blood doping or erythropoietin (EPO) injections, enhancing oxygen delivery for improved performance, especially in endurance sports. However, these practices are illegal and dangerous.

Understanding hemoglobin and hematocrit isn’t just important for medical professionals but for anyone who cares about their health. I hope this post has provided a clear and engaging explanation of these concepts. The story of Rafael Rangel serves as a reminder of the sacrifices made by scientists for the advancement of human health. Thank you all, and until next time!

Thank you @dexsyluz and @aaliarubab for this very Hematology topic. I'd like to invite @huzaifanaveed1, @kouba01, @irawandedy, and @01eh to participate in this module

Best,
Dr. @abdu.navi03