Blood Composition and Cell Production Quiz

Blood Composition

• Blood is a modified connective tissue crucial for transporting oxygen, nutrients, and waste products.
• It consists of plasma (fluid portion) and blood cells (solid portion).
• Blood cells include specialized cells (erythrocytes and leukocytes) and cell fragments (platelets or thrombocytes).

Blood Cell Production

• All blood cells originate from pluripotent stem cells in the red bone marrow through a process called hemopoiesis.
• Myeloid progenitor cells, derived from pluripotent stem cells, differentiate into:
  • Proerythroblasts, which develop into erythrocytes during erythropoiesis.
  • Myeloblasts, which develop into leukocytes during leukopoiesis.
  • Megakaryoblasts, which develop into thrombocytes during thrombopoiesis.
• Lymphoid progenitor cells, also derived from pluripotent stem cells, differentiate into lymphocytes during leukopoiesis.

Erythropoiesis

• Erythropoiesis is the process of red blood cell production.

Erythrocytes (Red Blood Cells)

• Erythrocytes constitute about 95% of blood cells.
• They lack nuclei and are responsible for oxygen transport.
• Erythropoietin, a hormone primarily produced by the kidneys, regulates erythropoiesis and stimulates stem cell differentiation.
• Hypoxia (low blood oxygen levels) triggers erythropoietin release.
• Vitamin B12 and folic acid are essential for DNA synthesis and RBC maturation.
• Hemoglobin, a pigmented protein within erythrocytes, is responsible for their red color and oxygen binding.

Erythrocytes Morphology

• Erythrocytes can be classified based on size:
  • Microcytic (smaller than normal)
  • Normocytic (normal size)
  • Macrocytic (larger than normal)
• Erythrocytes can also be classified based on hemoglobin content:
  • Hypochromic (lower than normal hemoglobin)
  • Normochromic (normal hemoglobin)
  • Hyperchromic (higher than normal hemoglobin)

Leukocytes (White Blood Cells)

• Leukocytes are spherical cells with nuclei.
• They lack hemoglobin and are classified based on the presence or absence of cytoplasmic granules.

Granulocytes

• Granulocytes have granules in their cytoplasm.
• Types of granulocytes include:
  • Neutrophils
  • Eosinophils
  • Basophils

Agranulocytes

• Agranulocytes lack granules in their cytoplasm.
• Types of agranulocytes include:
  • Lymphocytes
  • Monocytes

Platelets (Thrombocytes)

• Platelets are cell fragments responsible for blood clotting.
• They form a thrombus (plug) to seal breaks in the circulatory system.

Complete Blood Count (CBC)

• CBC is a test that analyzes the components of blood, including red and white blood cells, platelets, and hemoglobin.

Hemocytometer (Counting Chamber)

• A hemocytometer is a tool used for manual cell counting, primarily for blood cells.

Cell Counter (CBC Machine)

• A cell counter automatically counts cells in a blood sample using optical or electrical sensors.

Blood Smear (Film)

• A blood smear is a thin sample of blood spread on a glass slide and stained for microscopic examination.

CBC Report Components

• CBC reports include various parameters:
  • Hemoglobin (Hb)
  • Red Blood Cell Count (RBC)
  • Hematocrit (Hct)
  • Red Blood Cell Indices (MCV, MCH, MCHC, RDW)
  • Platelets
  • Total White Blood Cell Count (WBC)
  • Differential White Blood Cell Count

Hemoglobin Concentration (Hb)

• Hemoglobin concentration (Hb) reflects the oxygen-carrying capacity of blood.
• Low Hb levels indicate anemia.
• Reference ranges for adult Hb are:
  • Men: 14-17.5 g/dL
  • Women: 12.3-15.3 g/dL

Erythrocyte Count (RBC)

• RBC count is the number of red blood cells per unit volume of blood.
• Increased RBC count can be due to:
  • Polycythemia vera
  • High altitude
  • Dehydration
• Decreased RBC count can be due to:
  • Anemia
  • Blood loss
  • Bone marrow disorders