Hemoglobin (Hb) definition with it's normal count and Functions - QS Study
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Hemoglobin (Hb) may be defined as a vital conjugated protein present inside the Red Blood Cells (RBC). It is the protein molecule in red blood cells that bear oxygen from the lungs to the body’s tissues and returns carbon dioxide from the tissues back to the lungs.

Component: Two parts

(i) Heam = 4%

(ii) Globin = 96%

In male: Range: 14-18gm / 100 ml of blood (Average: 153 gm/100 ml. of blood).

In Female: Range: 12-155 gm/100 ml of blood (Average: 14.0 gm/100 ml of blood).

At birth: 23 gm/di

At 1st year: 10 gm /100 mL

A low hemoglobin count is normally defined as fewer than 13.5 grams of hemoglobin per deciliter (135 grams per liter) of blood for men and less than 12 grams per deciliter (120 grams per liter) for women.

Fig: Hemoglobin (Hb) Function

Function – It forms an unbalanced, reversible bond with oxygen; in the oxygenated state it is called oxyhemoglobin and is light red; in the condensed state it is purplish blue. If in lungs, the oxygen levels are high the hemoglobin shows a better affinity towards the oxygen molecules and as it bounds to more oxygen, this property of affinity increases and vice versa.

Transport: It transports oxygen and carbon dioxide between lungs and tissue.

Acid-base regulation – Hb is an important blood buffer and maintain pH of Blood.

HbO2 + CO ↔ HbCO + O2


Pigment formation: Various pigments like bilirubin, biliverdin, etc. formed from Hb.

Reservoir: It reserves iron and protein.

Blood pressure regulation: It regulates B. P by increasing blood viscosity.

Homeostasis: It maintains homeostasis of blood.