| Bone marrow
is the soft spongy material that fills the core of the bone. It is the
this blood-forming tissue that produces the erythrocytes, leukocytes,
and platelets. Erythrocytes (RBCs) carry oxygen.
Erythropoiesis is the production of erythrocytes or RBCs, is
stimulated by hypoxia, and controlled hormonally by erythropoietin
which is secreted by the kidney. Erythropoiesis is also influenced by
nutrients, iron, vitamin B12, and folic acid. Reticulocytes
are immature erythrocytes. The reticulocyte count measures
the rate at which new RBCs appear in the circ. Reticulocytes mature in
about 48 hrs of release into circulation.
Hemoglobin (HGB)
is the major component of RBCs with the function of carrying oxygen.
Leukocytes
- (white blood cells) provide protection against infectious agents,
other foreign substances and defective tissue. There are 3 classes
granulocytes, monocytes, lymphocytes. Main function of first two
are the removal of bacteria and foreign particles that invade the body
called phagocytosis. Main function of lymphocytes is related
to the immune response.
Platelets prevent blood loss through
breaks in vessel walls, by clumping together (aggregation or
agglutination). Approximately 55% of blood volume is made up of plasma,
and 45% of cells. Plasma is a pale yellow liquid consisting of water and
solutes. It contains albumin, fibrinogen and globulins. Blood components
develop from a common stem cell, but as they mature and differentiate
into several distinct cell types. This process is called hematopoiesis.
Also, in the adult, active production of marrow is limited to the ends
of the long bones, vertebrae, flat cranial bones, sternum, ribs,
scapulae, clavicles, pelvis, and sacrum.
Platelets or thrombocytes are not true
cells. They have no nucleus, are oval or spindle shaped, and formed by
shedding or segmenting of megakaryocytes. They prevent blood loss by (1)
sticking together, (2) secreting chemicals such as prostaglandins that
cause vasoconstriction, & by (3) initiating coagulation of the blood.
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Anemias
of Deficient Red Cell Production:
Iron Deficiency anemia - Blood loss anemia
Megaloblastic Anemias:
Pernicious anemia – B12 Folic Acid Deficiency - Aplastic anemia -
Chronic Disease Anemia
Hemolytic Anemias:
G6PD Deficiency Anemia - Hemolytic anemia - Thallasemia - Sickle cell
disease
Deficient Red Blood
Cell Anemias: Iron Deficiency anemia
Megaloblastic Anemias
Pernicious anemia (B12) Folic Acid Deficiency Aplastic anemia
Iron Deficiency
Anemia: Etiology & Pathophysiology inadequate diet (lacking in
meats, eggs, dried fruits, legumes, dark green leafy veggies, whole
grain & enriched cereals & breads) malabsorption blood loss hemolysis
(dialysis) Symptoms related to impaired O2 transport. Treatment =
increase iron intake, & give Ferrous Sulfate |
