Human Blood Circulatory System

About Red Blood Cell(Erythrocytes)

• A RBC has a strange shape -- small biconcave disc that is round and flat, sort of like a shallow bowl.
• A RBC has no nucleus. The nucleus is extruded from the cell as it matures.
• A RBC can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries
• A RBC contains hemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it. 

The primary function of red blood cells is to transport oxygen from the lungs to the cells of the body. RBCs contain a protein called hemoglobin that actually carries the oxygen. Hemoglobin combines loosely with oxygen in the lungs where the oxygen level is high and then easily releases it in the capillaries where the oxygen level is low. Each molecule of hemoglobin contains four iron atoms. Each iron atom can bind with one molecule of oxygen (which contains two oxygen atoms, called O2) for a total of four oxygen molecules or eight atoms of oxygen for each molecule of hemoglobin. The iron in hemoglobin gives blood its red color.

Red Blood Cell / Erythrocytes

 About White Blood Cell(Leucocytes)

Our blood also contains white blood cells. There are several types of white blood cells. White blood cells are larger than red blood cells and have nuclei. They have different shapes and sizes. White blood cells are located in the lymph nodes and the spleen. Their main function is to produce antibodies that destroy foreign chemicals and pathogenic microorganisms in the blood. They are the “soldiers” of the body that protect it against disease(s).

White Blood Cell / Leucocytes

Lymphocyte among the erythrocytes

Eosinophil among the erythrocytes

About Platelet

Platelets are small fragments of cells formed in the bone marrow. Their function is to clot blood. For example, if you cut your finger accidentally with a knife, blood flows from your finger. The platelets trap red blood cells. The blood changes into a thick substance which is called a blood clot. This stops the bleeding. The clot hardens to form a scab. 

 

 

 Differences between artery and vein