Components of
Blood
Structure of Blood
• Adult = 5 liters
• Composition
• Plasma
• Serum
• Cellular components
• Red (Erythrocytes)
• White (Leukocytes)
• Platelets (Thrombocytes)
Plasma
• Straw colored
• Liquid part of blood
• Contains:
• Salts
• Glucose
• Amino acids
• Vitamins
• Urea
• Proteins
• Fats
Erythrocytes – Red Blood Cells
• Shape = biconcave discs, donut-shaped
• Primary function is to transport
oxygen
• Hemoglobin
• Gives red color
• Heme = iron,
globin = protein
• Normal ranges (per microliter)
• 4.2 – 6.2 million / uL
Leukocytes – White blood cells
• Larger than erythrocytes
• Primary function is to fight infection
• Different types
• Neutrophils
• Eosinophil's
• Basophils
• Lymphocytes
• Monocytes
• Average count = 5 -10 thousand per uL
Neutrophils (60%)
• Body’s main defense against bacteria
• Kill bacteria by phagocytosis
• Have multi-lobed, segmented (polymorphonuclear)
nucleus (also called PMNs, polys or segs)
• When bacterial infection is present, increase in
neutrophil number
Eosinophils (2%)
• Responsible for combating multicellular parasites
• Active during allergic reactions (help produce
inflammation)
Basophils (1%)
• Active during allergic responses
• Releases histamine (causes blood vessels to leak
and attracts WBCs) and heparin (prevents clotting so
WBCs can reach the bacteria)
Monocytes (4%)
• Kill bacteria
• Destroy old, damaged, and dead cells
• Found in liver, spleen, lungs, lymph nodes, skin and
intestine
• Monocytes stay in blood for an average of 10-20 hours
and then go into the tissues, where they become tissue
macrophages and live for months to years
Lymphocytes (4%)
• Complex cells that direct the body’s immune system
• Different than other WBC because they have a memory
and can recognize invading bacteria and viruses
• Two types
• T-cells (75% of lymphocytes)
• B-cells
Thrombocytes - Platelets
• Make the blood clot
• Smallest solid component of blood
• Not cells – fragments of megakaryocytes (very large
cells formed in bone marrow)
• Live an average of 10 days
• Average count = 12 – 300 thousand / uL