Plasma and the Cellular Elements of Blood
• Blood makes up 1/4 of extracellular fluid
• Buffer between cells and external environment
• Carry materials from parts to parts
Plasma is Extracellular Matrix
• Plasma is the fluid portion of the blood.
• Water is main component, take up 92%
• Protein 7%
• Dissolved organic molecules (AA, glucose, lipids etc, ions) 1%
• Plasma is identical to interstitial lfuid but it has one extra : plasma proteins
• Albumins are the most prevalent type. (contributor to colloid osmotic pressure, carrier of various
♦ And 9 other proteins make up 90%
♦ Globulin (clotting factors, enzymes, antibodies, carriers), fribrinogen (clotting),
transferrin (transport iron)
♦ Livers makes the proteins (except some globulins, immunoglobins or antibodies are
made by blood cells)
• Presence of proteins make the osmotic pressure of blood higher than interstitial fluid -> the
gradient pull water into capillaries from interstitial fluid.
Cellular Elements Include RBCs, WBCs, and platelets
• 3 main cellular elements
1. Red blood cells (erythrocytes) – lost nuclei
Transport oxygen and carbon dioxide
2. White blood cells (leukocytes) - only functional cells
Key role in immune response, work carry out in tissue not circulatory system
5 types of mature white blood cells
2) Monocytes (those that leave circulation and enter tissue develop into
5) Basophils (tissue basophiles called mast cells)
Neutrophils, Monocytes, macrophage are called phagocytes
Lymphocytes are called immunocytes because they are responsible for immune
Basophils, eosinophils and neutrophils are called granulocytes (granular
3. Platelets (thrombocytes) – fragments split off megakaryocytes
Instrumental in coagulation Blood is composed of 1) Plasma and 2) Cellular elements. Plasma is composed of 1) water, 2) ions
3)organic molecules 4) vitamins 5) gases. Organic molecules include proteins which have different
types. Cellular components are composed of 1) red blood cells, 2) white blood cells, 3) platelets.
White bloods cells have 5 types.
Blood Cell Production
• 3 main cellular elements
• Bloods cells are descendants of precursor pluroipotent hemotopoietic stem cell.
• Found in bone marrow
• First become uncommitted stem cells, then commited progenitor cells. Then into white blood
cells, megakaryocytes (platelets), erythroblast (then into red blood cell)
Blood Cells Are Produced in the Bone Marrow
• Hematopoiesis (synthesis of blood cells) begins in embryonic development
• Specialized cell in the yolk sac become blood cells.
• As embryo develops, blood cell production spreads from yolk sac to liver, spleen and bone
• By birth, liver and spleen no longer produce blood cells.
• Hematopoiesis continues in the marrow of all bones till age five.
• In adults, only pelvis, spins, ribs, cranium and proximal ends of long bonds produce blood cells.
• Active bone marrow is red -> hemoglobin
• Inactive marrow is yellow -> adipocytes (fat cells)
• Active bone marrow has 25% red blood cell/ 75% destined for white blood cells.
• WBS has less life span, must be replaced frequently
Hematopoiesis is Controlled by Cytokines
• Cytokines are peptides or proteins released from a cell that affect the growth or activity of
• Examples of cytokines