Definition of HEMOGLOBIN


Hemoglobin is a noun that refers to a protein molecule found in red blood cells responsible for transporting oxygen from the lungs to tissues throughout the body and transporting carbon dioxide from tissues back to the lungs. It encompasses several key aspects:

Structural Composition: Hemoglobin consists of four subunits, each containing a heme group and a globin chain. The heme group contains iron (Fe) atoms, which bind oxygen molecules, while the globin chains provide structural support and stability to the molecule.

Oxygen Transport: Hemoglobin undergoes reversible binding with oxygen molecules in the lungs, forming oxyhemoglobin. This oxygenated form of hemoglobin travels through the bloodstream, releasing oxygen to tissues with lower oxygen concentrations, such as muscles and organs.

Carbon Dioxide Transport: In tissues with high carbon dioxide concentrations, hemoglobin binds to carbon dioxide molecules, forming carbaminohemoglobin. This facilitates the transport of carbon dioxide from tissues to the lungs for elimination during exhalation.

Regulation of pH and Acid-Base Balance: Hemoglobin also plays a role in buffering the pH of blood by binding to hydrogen ions (H⁺) and other acidic substances, helping to maintain the blood’s acid-base balance within a narrow physiological range.

In summary, hemoglobin is a vital protein molecule found in red blood cells that facilitates the transport of oxygen and carbon dioxide in the bloodstream, contributing to cellular respiration, pH regulation, and overall physiological function in the human body.

Examples of HEMOGLOBIN in a sentence

  • Hemoglobin is a protein found in red blood cells that carries oxygen from the lungs to the body’s tissues.
  • A low level of hemoglobin in the blood can indicate anemia.
  • The doctor ordered a blood test to check her hemoglobin levels.
  • Iron is essential for the production of hemoglobin in the body.
  • Hemoglobin binds to oxygen in the lungs and releases it in tissues that need it.
  • The athlete’s high hemoglobin levels contributed to his endurance and stamina.
  • Sickle cell anemia affects the structure of hemoglobin in red blood cells.
  • The laboratory technician analyzed the patient’s hemoglobin sample for abnormalities.

Etymology of HEMOGLOBIN

The term hemoglobin is derived from the Greek words “haima” (blood) and “globin” (protein). Here’s the breakdown:

  • Haima: From the Greek word “αἷμα” (haima), meaning “blood.” It refers to the red bodily fluid that circulates in humans and other vertebrates, carrying oxygen from the lungs to the tissues and carbon dioxide from the tissues back to the lungs.
  • Globin: From the Greek word “globos” (γλόβος), meaning “ball” or “sphere.” In this context, it refers to the proteinaceous component of hemoglobin.

Therefore, hemoglobin is a protein found in red blood cells that is responsible for transporting oxygen from the lungs to the tissues and carbon dioxide from the tissues back to the lungs. The name reflects its composition as a globular protein (globin) present in blood (haima), emphasizing its crucial role in the oxygenation and circulation of blood throughout the body.


  • Hb
  • Red cell protein
  • Blood pigment
  • Oxygen carrier
  • Iron-containing protein
  • Heme
  • Erythrogen
  • Oxyhemoglobin


  • Bloodless
  • Anemic
  • Oxygen-deficient
  • Non-hemoglobin
  • Hemoglobin-deprived
  • Iron-deficient
  • Hypoxic
  • Blood-poor


  • Red blood cells
  • Oxygenation
  • Anemia
  • Blood cells
  • Iron
  • Oxygen transport
  • Heme synthesis
  • Oxygen saturation

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