Red Blood Cells (erythrocytes) - Cells with a biconcave shape and no nucleus. Red blood cells contain hemoglobin, a red pigment that combines with oxygen to form the compound oxyhemoglobin. The function of red blood cells is to carry oxygen from the lungs to all the cells in the body (for respiration). Red blood cells make up 45% of the blood.
White Blood Cells - The function of white blood cells is to protect the body against pathogens. White blood cells make up less than 1% of the blood. There are two types of white blood cells, these are phagocytes and lymphocytes.
- Phagocytes engulf pathogens by trapping them in a vacuole and then digests (breaks down) them using enzymes.
- Lymphocytes produce antibodies (specific to the pathogen) to destroy the microorganism.
- Memory lymphocytes give us immunity to specific diseases.
Platelets - The function of platelets is to release chemicals in order to make a blood clot. This prevents further blood loss and the entry of pathogens into the body. Platelets are fragments of larger cells which are produced in the bone marrow. Platelets make up less than 1% of the blood.
