MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

ANATOMY, PHYSIOLOGY, PATHOLOGY

CHAPTER 4. BLOOD SYSTEM

PATHOLOGY OF THE BLOOD SYSTEM

QUANTITATIVE BLOOD CHANGES

1. ANEMIAS

1.2. ANEMIAS DUE TO IMPAIRED HEMOPOIESIS

Anemias caused by impaired hemopoiesis are subdivided into deficiency, hypoplastic, and aplastic anemias.

Deficiency anemias occur due to a shortage of iron, vitamin B 12, or Folic acid.

Iron-deficiency anemias are the most common. Their causes may include insufficient dietary iron intake (nutritional iron-deficiency anemia), increased physiological demands during Pregnancy, Lactation, or Puberty in girls (juvenile chlorosis), as well as impaired iron absorption following gastric resection (agastric anemia) or bowel surgery (anenteral anemia). All iron-deficiency anemias are hypochromic, with the color index dropping to 0.5-0.6, alongside qualitative alterations in red Blood Cells such as anisocytosis and poikilocytosis.

B₁₂-folate-deficiency (pernicious) anemias result from a deficiency of gastromucoprotein (Castle's intrinsic factor), small intestinal lesions, and competitive uptake of the vitamin by intestinal parasites.

Castle's intrinsic factor (gastromucoprotein) is synthesized by the parietal Cells of the gastric fundic glands and ensures the absorption of vitamin B₁₂ into the bloodstream, where it is stored in The Liver and activates folic acid. The presence of vitamin B₁₂ and folic acid in the Bone Marrow promotes normal erythropoiesis. The loss of gastromucoprotein secretion may be associated with hereditary inadequacy of the fundic glands, autoimmune processes, or gastric surgeries. The most pronounced changes are observed in the bone marrow, Spinal Cord, and gastrointestinal tract.

The bone marrow of flat and tubular bones acquires a vivid crimson-red color (resembling raspberry jelly). Erythropoiesis shifts to a megaloblastic type, with blood destruction processes prevailing over hemopoiesis.

Generalized atrophic changes occur in the gastrointestinal tract; in particular, the Tongue becomes smooth and glossy ("lacquered tongue") with red patches.

In the posterior and lateral columns of the spinal cord, myelin breaks down, manifesting as a decrease in tactile sensitivity. Such degenerative processes in nerve fibers are known as funicular myelosis.

B₁₂-folate-deficiency anemia is hyperchromic, with the color index reaching 1.3 or higher.

Hypoplastic and aplastic anemias develop As a result of bone marrow suppression caused by ionizing radiation, certain toxins (benzene, heavy metal salts), and medications (cytostatics, sulfonamides). Some forms of these anemias are hereditary in origin.