Blood Pathologies

Components of Whole Blood Figure 17.2

Anemia refers to any condition in which there is a reduction in the number of RBCs or a reduction in the concentration of normal hemoglobin Anemia can be classified according to etiology (cause) or on the basis of morphology – RBC SizeRBC Size RBC ColorRBC Color Microcytic: small sizeMicrocytic: small size Hypochromic: pale colorHypochromic: pale color Normoctic: normal sizeNormoctic: normal size Normochormic: normal colorNormochormic: normal color Macrocytic: large sizeMacrocytic: large size Hyperchromic: dark colorHyperchromic: dark color

Anemia – blood has abnormally low oxygen- carrying capacity – It is a symptom rather than a disease itself – Blood oxygen levels cannot support normal metabolism – Signs/symptoms include fatigue, paleness, shortness of breath, and chills

Pernicous Anemia: caused by vitamin B 12 deficiency A.Can be either macrocytic, hyperchromic or macrocytic normochromic B.Note the enlarged, dark red blood cells, and the hypersegmented neutrophil in this smear

Iron Deficiency Anemia caused by iron insufficiency leading to decreased hemoglobin synthesis A.Is an example of microcytic, hypochromic anemia B.Note the small erythrocytes of varying sizes and the large area of central pallor

Sickle Cell Anemia: caused by a single amino acid substitution in the β chain of hemoglobin (valine replaces glutamic acid) Genetic: recessive trait; African; African – Americans; Middle Eastern; even Italian and Greeks; having sickle cell trait (one recessive allele seems to confer protection from Malaria)

Disorders Related to Leukocytes: I.Chronic Lymphocytic Leukemia -cancer caused by malignant lymphocyte progenitor cells in bone marrow

Leukocytes Disorders: Leukemias Leukemia refers to cancerous conditions involving WBCs Leukemias are named according to the abnormal WBCs involved – Myelocytic leukemia – involves myeloblasts – Lymphocytic leukemia – involves lymphocytes Acute leukemia involves blast-type cells and primarily affects children Chronic leukemia is more prevalent in older people

II.Eosinophilia many causes, including malignancy, connective tissue diseases, parasitic diseases, allergies; in some cases, no known cause Note the two normal looking eosinophils in the field

Hemostasis Disorders: Thromboembolytic Conditions Thrombus – a clot that develops and persists in an unbroken blood vessel – Thrombi can block circulation, resulting in tissue death – Coronary thrombosis – thrombus in blood vessel of the heart

Embolus – a thrombus freely floating in the blood stream – Pulmonary emboli can impair the ability of the body to obtain oxygen – Cerebral emboli can cause strokes

Unnecessary clotting is prevented by endothelial lining the blood vessels Platelet adhesion is prevented by: – The smooth endothelial lining of blood vessels – Heparin and PGI 2 secreted by endothelial cells – Vitamin E quinone, a potent anticoagulant Factors Preventing Undesirable Clotting

Substances used to prevent undesirable clots: – Aspirin – an antiprostaglandin that inhibits thromboxane A 2 – Heparin – an anticoagulant used clinically for pre- and postoperative cardiac care – Warfarin – used for those prone to atrial fibrillation Prevention of Undesirable Clots

Hemophilias – hereditary bleeding disorders caused by lack of clotting factors – Hemophilia A – most common type (83% of all cases) due to a deficiency of factor VIII – Hemophilia B – due to a deficiency of factor IX – Hemophilia C – mild type, due to a deficiency of factor XI Hemostasis Disorders: Bleeding Disorders