Hematolymphoid Flashcards
Lymphoid tissue
Location; role
- Located in the lymphoid tissue and blood (lymphocytes)
- Primary (BM & thymus) vs secondary (lymph node, spleen, MALT)
- Role: Adaptive immunity
Myeloid tissue
Location; role
Location:
- Bone marrow (blood cell precursors)
- Blood (erythrocytes, platelets, granulocytes, monocytes)
Role: transport oxygen (RBCs), clotting (platelets), fight infection (WBCs)
Hematopoiesis
Different cell lines, each undergo differentiation into a committed cell type
Lymphopoeisis
Location and types of cells
- B cells mature in BM
- T cells mature in thymus
Hematopoiesis (Fetal, infant, adult)
- Fetal: HSCs in yolk sac migrate to liver, BM, spleen, LNs and thymus
- Infant: Extramedullary hematopoiesis stops
- Adult: Hematopoiesis occurs in flat bones, ribs, vertebrae, and end of long bones (If BM destroyed, extramedullary hematopoiesis in spleen, liver and lymph nodes)
Components and composition of blood
Blood quantity; components; blood measurements
Quantity: 5L of blood
Components:
- Plasma (water, plasma proteins, solutes)
- RBCs
Measurements:
- Complete blood count (CBC): tests whether components are within normal range
- Hematocrit: ratio of packed RBC to total volume (~40-45%)
Serum
Plasma without coagulation proteins (blood clotting factors: fibrinogen, prothrombin, coagulation factors)
RBC morphology
Normal
Normal: biconcave disk (no nucleus) (abnormal: sickle cell, etc.)
Hemoglobin
Function; structure
Function: carries oxygen
Structure: Consists of 4 globin chains (each globulin chain has a heme containing Fe to carry oxygen; 4 polypeptide chains designatied alpha, beta, delta and gamma - normal adults mostly HbA)
RBC life cycle
- Circulation for 120 days
- Erythropoietin (growth factor) released by kidneys promotes erythropoiesis in BM and release
- Spleen sequesters old RBCs (components reutilized or excreted)
Anemia
Definition; assessment; etiological classification
Definition: Reduction of total circulating red cell mass below normal limits
Assessment: Hemoglobin levels (Hb < 130 males; < 115 females)
Etiological classification: Increased loss, increased destruction, decreased production
Anemia
Morphological classification: RBC size (microcytic, normocytic, macrocytic) and hemoglobin content (hypochromic (pale), normochromic (normal))
Anemia
1) Iron deficiency
2) Massive blood loss
3) Vitamin B12 and/or folic acid deficiency
4) Sickle cell
1) Hypochromic microcytic
2) Normochromic normocytic
3) Macrocytic
4) Abnormal shape
Anemia Etiological Classification
Increased factors
Increased loss (bleeding): acute vs chronic
Increased destruction (hemolytic anemia):
Destruction of abnormal RBCs:
- Inherited: red cell membrane disorders, anzyme deficiencies, abnormal Hb)
- Acquired: PNH
Destruction of normal RBCs:
- Immune mediated
- Mechanical (repetitive trauma)
- Infections
- Chemical/toxic injury