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• Blood


  Is the essence of life
• Blood


  • Is a type of connective tissue that consists of cells and cell fragments surrounded by a liquid matrix
  • Formed elements- the cells and cell fragments
  • Less than half of total blood volume
  • Plasma- the liquid component
  • More than half of the total blood volume
• Total Blood Volume: Male- 5 to 6L; Female- 4to 5L
• Functions of blood


  • Transport of gases, hormones, nutrients, and waste products
  • Transport of processed molecules
  • Transport of regulatory molecules
  • Regulation of pH and osmosis
  • Maintenance of body temperature
  • Protection against foreign substances
  • Clot formation
• Plasma


  Is a pale-yellow fluid that consist of about 91 % water, 7 % proteins, and 2 % other substances, such as ions, nutrients, gases, and waste products
• Composition of plasma


  • Albumin- makes up 58% of the plasma proteins. It contributes in the osmotic pressure in the blood and transport of molecules in the blood
  • Globulins- account for 38 % of the plasma proteins. Part of the immune system i.e. antibodies and complement. It transports molecules in the blood
  • Fibrinogen- a clotting factor that constitute 4% of plasma proteins. Activation of clotting factors results in the conversion of fibrinogen to fibrin
  • Serum- is a plasma without the clotting factors
• Formed elements


  The cells and cell fragments in blood
• Production of formed elements (hematopoiesis)

  1. Stem cell/ Hemocytoblast- produce all formed elements of blood. It differentiates to give rise to different cell lines

  2. Normoblast- last stage of RBC formation with nucleus

  3. Reticulocytes- immature RBCs
• Red Blood Cells (RBCs)

  • Disk shaped cells with edges that are thicker than the enter of the cell. (Mature RBCs lack a nucleus)
  • It lives for about 120 days for males and 110 days for female
• Hemoglobin


  • Consists of four proteins chains and four heme groups
  • Globin- protein that bound to 1 heme
  • Heme- red-pigmented molecules
  • 1 iron atom- necessary for the normal function of hemoglobin. 2/3 of the body's iron is found in hemoglobin
• Women need more iron than men- because women loose iron as a result of menstruation
• Carbonic anhydrase (enzyme)


  Found primarily inside RBC's, catalyzes a reaction that converts CO2 and H2O into a hydrogen ion and a HCO3
• 23% of CO2 in blood is bound to hemoglobin or other blood proteins. Remaining 30% is transported dissolved in plasma
• RBC production


  1. Cell division requires the B vitamins folate and B12 which are necessary for the synthesis of DNA. Iron is required for the production of hemoglobin

  2. RBC production is stimulated by low oxygen levels
• Decrease in RBC or defective Hgb, Lung diseases, High altitude, inability of the cardiovascular system to deliver blood to tissue, and increased tissue demands for O2 i.e. exercise

  Increase RBC production by increasing the formation of glycoproteins erythropoietin by the kidneys
• RBC breakdown


  1. Old, abnormal, or damaged RBC's are removed from the blood by macrophages located in the spleen and liver & red bone marrow

  2. The globin part of the molecules is broken down into amino acids that are reused to produce other proteins

  3. The iron released from heme is transported in the blood to the red bone marrow and is used to produced new hemoglobin

  4. The heme molecules are converted to bilirubin, a yellow pigment molecule

  5. Bilirubin normally is taken up by the liver and converted by bacteria into other pigments
• White Blood Cells (Leukocytes)


  • Are spherical cells that lack hemoglobin
  • WBC's form a thin, white layer of cells between plasma and RBC's
  • They are larger than RBC's and each has a nucleus
• Functions of WBC's


  • To protect the body against invading microorganisms
  • To remove dead cells and debris from the tissues by phagocytosis
• Types of Granulocytes


  • Neutrophils (Neutral)- the most common type of WBC's, have small cytplasmic granules that stain with both acidic and basic dyes. Contains two-four lobes nucleus
  • Basophils (Basic)- the least common of all WBC's, contains large cytoplasmic granules that stain blue or purple with basic dyes
  • Eosinophiles (eosin, and acidic dye)- contains cytoplasmic granules that sati bright red with eosin, and acidic stain. Contains 2-lobed nucleus
• Types of Agranulocytes


  • Lymphocytes- comprise 20-15% of WBCs. They are the smallest WBCs, most of which are slightly larger than RBCs
  • Monocyte- (comprise 3%-8% of WBC. Monocyte normally remain in the circulation, become transformed into Macrophages, and migrate through various tissues)
• Lymphocytes


  • Originate in red bone marrow that migrate through the blood to lymphatic tissues where they can proliferate and produce more lymphocytes
  • The majority of the body's total lymphocyte population is in the lymphatic tissues: Lymphnodes, Spleen, Tonsils, Lymphatic nodules, Thymus
  • B-Cells- can be stimulated by bacteria or toxins to divide and form cells that produce protein called antibodies
  • T-Cells- protect against viruses and other intracellular microorganisms by attacking and destroying the cells in which they are found. T-cells are involved in the destruction of tumor cells and tissue graft rejection
• Macrophages


  Stimulate responses from other cells by releasing chemical signals and phagocytizing and processing foreign substances, which are presented to lymphocytes
• Platelets


  • Are minutes fragments of cell consisting of small amount of cytoplasm surrounded by a plasma membrane
  • Platelets are roughly disck-shaped and average about 3um in diameter
  • The surface of platelets has a glycoproteins and proteins that allow platelets to attach to other molecules, such as collagen in connective tissue
  • Contain actin and myosin, which can cause contraction of the platelet
  • The life expectancy of platelets is about 5-9days
  • They are produce in the red marrow and are derived from megakaryocytes
• Platelet plug formation


  1. Platelet adhesion- occur when platelet bind to collagen exposed by local blood vessel damage

  2. As platelet adhere to collagen, they become activated; in the platelet released action- ADP, thromboxanes, and other chemicals are extruded from the platelets cytosine

  3. As the platelet become activated, they change shape and express fibrinogen receptors that can bind fibrinogen, a plasma protein. In Platelet Aggregation- fibrinogen forms a bridge between the fibrinogen receptors of different platelets, resulting in the formation of a platelet plug

  4. Activated platelets express phospholipids (platelet factor III) and coagulation factor V, which are important in the coagulation cascade
• Hemostasis


  The stoppage of bleeding. Is very important to the maintainance of homeotasis
• Factors that produce Vascular spasm

  • Contraction of smooth muscle within the wall of the vessel
  • Chemicals: Thromboxanes- dervied from certain prostagladin, Endotheline- a peptide release by edothelial cells
• Platelet plug formation is very important in maintaining the integrity of the circulatory systems because small tears occur in the smaller vessels and capillaries many times each day, and plate plug formation quickly closes them
• People who lack the normal number of platelets tend to develop numerous small hemorrhages in their skin and internal organs
• Platelet plug formation


  1. Platelet adhesion

  2. Platelet activation

  3. Platelet aggregation
• Platelet adhesion


  Occurs when platelets bind to collagen exposed by local blood vessel damage
• Von Willebrand Factor (vWF)

  • Protein produced and secreted by blood vessel endothelial cells
  • Forms a bridge between collagen and platelets by binding to platelet surface receptors and collagen
• Platelet activation


  1. Platelet release ADP, thromboxanes, and other chemicals

  2. Platelets change shape and express fibrinogen receptors
• Platelet aggregation


  Fibrinogen forms a bridge between the fibrinogen receptors of different platelets, resulting in the formation of a platelet plug
• Activated platelets


  • Express phospholipids (platelet factor III) and coagulation factor V, which are important in clot formation
• Blood clotting


  Results in the formation of a clot, a network of fibrin fibers that traps blood cells, platelets, and fluid
• Extrinsic pathway of blood clotting

  1. Begins with thromboplastin (tissue factor) released from damaged tissue

  2. Thromboplastin forms a complex with factor VII that activates factor X, which is the beginning of the common pathway
• Intrinsic pathway of blood clotting

  1. Begins when plasma factor XII comes into contact with collagen in damaged blood vessels

  2. Activated factor XII stimulates factor XI, which in turn activates factor IX

  3. Activated factor IX joins with factor VIII, platelet phospholipids, and calcium to activate factor X, which is the beginning of the common pathway
• Common pathway of blood clotting

  1. Activated factor X, factor V, platelet phospholipids, and calcium form prothrombinase

  2. Prothrombinase converts prothrombin into thrombin

  3. Thrombin converts fibrinogen into fibrin, which forms the fibrous network of the clot
• Thrombin


  • Stimulates factor XII activation to stabilize the clot
  • Activates many clotting factors, creating a positive feedback loop to produce more thrombin
  • Has a positive feedback effect on platelet activation
• Anticoagulants


  • Prevent coagulation factors from initiating clot formation
  • Only unable to prevent clot formation at the site of injury where coagulation factors are highly concentrated