ANA 110

🩸 Exam 1 Review: Blood & Hematology (Portage Learning)

1. Formed Elements of Blood

  • Erythrocytes (RBCs): Transport oxygen and some carbon dioxide.

    • Lifespan: ~120 days.

    • Shape: Biconcave disk → increases surface area for gas exchange.

    • Lack nucleus & organelles → rely on anaerobic respiration, don’t consume the oxygen they carry.

  • Leukocytes (WBCs): True cells with nucleus & organelles. Provide immune defense.

  • Platelets (Thrombocytes): Cell fragments from megakaryocytes. Essential for clotting.

👉 Exam tip: Only leukocytes are “true cells.” RBCs are most abundant; platelets are fragments.

2. Plasma & Plasma Proteins

  • Plasma composition: ~92% water, ~7% proteins, ~1% solutes.

  • Albumin: Most abundant; maintains osmotic pressure, transports lipids/hormones.

  • Globulins: Alpha & beta (transport), gamma (antibodies).

  • Fibrinogen: Clotting factor.

  • Other solutes: Electrolytes (Na⁺, K⁺, Ca²⁺), nutrients, gases, wastes.

👉 Exam tip: Albumin deficiency → ascites (fluid buildup in abdomen).

3. Hemoglobin

  • Structure: 4 globin chains (2 alpha, 2 beta) + 4 heme groups (iron).

  • Each hemoglobin binds 4 oxygen molecules.

  • Forms:

    • Oxyhemoglobin: Bright red, oxygen-bound.

    • Deoxyhemoglobin: Darker red, oxygen released.

    • Carbaminohemoglobin: CO₂ bound to hemoglobin.

  • Oxygen saturation (“percent sat”): Normal 95–100%.

👉 Exam tip: Oxygen binds to the iron ion in heme, not the globin chain.

4. Hematocrit & Polycythemia

  • Hematocrit: % of blood volume made up of RBCs.

    • Lower in females (less androgen stimulation).

  • Polycythemia: Elevated RBC count.

    • Causes: dehydration, high altitude, polycythemia vera (bone marrow cancer).

    • Danger: increases blood viscosity → higher blood pressure, strain on heart.

5. RBC Disorders (Anemias)

  • Iron deficiency anemia: Microcytic, hypochromic RBCs.

  • Pernicious anemia (B12 deficiency): Macrocytic, normochromic RBCs.

  • Hemorrhagic anemia: Blood loss (acute or chronic).

  • Hemolytic anemia: RBCs rupture prematurely.

  • Aplastic anemia: Stem cell deficiency → low RBC production.

  • Thalassemia: Faulty globin chains.

  • Sickle cell anemia: Genetic mutation → sickle-shaped RBCs, block capillaries.

👉 Exam tip: Iron deficiency = small pale cells; B12 deficiency = large normal-colored cells.

6. RBC Life Cycle & Breakdown

  • Production: Red bone marrow, ~2 million per second.

  • Removal: Macrophages in spleen, liver, bone marrow.

  • Breakdown products:

    • Globin → amino acids (recycled).

    • Iron → stored (ferritin) or transported (transferrin).

    • Heme → biliverdin (green), bilirubin (yellow).

      • Bilirubin → liver → bile → intestines.

      • Converted to urobilin (urine yellow) & stercobilin (feces brown).

  • Clinical signs:

    • Biliverdin → green bruises.

    • Bilirubin buildup → jaundice.

7. Key Exam Facts

  • Longest lifespan formed element: Lymphocytes (among WBCs).

  • Erythropoietin: Produced by kidneys in response to hypoxia.

  • Females have lower hematocrit: Less androgen exposure.

Dark red hemoglobin: Deoxyhemoglobin, not oxyhemoglobin