L24: Blood

Question 1

Elements of blood

Answer 1

1.) Plasma
2.) Formed elements
Upon centrifugation (top to bottom): plasma (proteins lipids hormones vitamins salts = yellow d/t bilirubin – whitish after high fat meal d/t chylomicrons), buffy coat (leukocytes and platelets), RBCs

Question 2

What is serum?

Answer 2

• Plasma with fibrinogen removed

Question 3

What are the formed elements of blood

Answer 3

• RBCs
• Leukocytes
  a. ) Granulocytes: NEB
  b. ) Agranulocytes: LM
• Thrombocytes (platelets)

Question 4

Composition of plasma

Answer 4

• 90% water
• Proteins:
  a. ) albumin (from liver) that helps maintain colloid osmotic pressure and transport – loss leads to edema
  b. ) globulins (alpha = ceruloplasmin Copper transport, AAT, protein C; beta = transferrins, angiostatins, plasminogens; gamma = antibodies)
  c. ) clotting factors (PT, fibrinogen, factor VII)
  d. ) complement proteins
  e. ) lipoproteins
• Hormones
• Electrolytes
• Dissolved gases

Question 5

What is polycythemia?

Answer 5

• Elevated RBC count

Question 6

What is anemia?

Answer 6

• Decreased in erythrocytes or reduction in Hb concentration

Question 7

Major Transmembrane proteins found in RBCs, function?

Answer 7

• Glycophorins (A,B,C): unknown function

- Band 3: transports bicarb and chloride across PM

Question 8

Discuss skeleton of RBC and defects to this skeleton

Answer 8

1. ) Band 4.1 anchors cytoskeletal components by complexing with spectrin, glycophorin and actin. Elliptocytosis = mutation in any one of these proteins causes transformation of RBCs into elliptocytes, non-functioning
2. ) Band 3, band 4.2, ankyrin and spectrin form another complex
   - Adducin promotes actin-spectrin association. Spherocytosis = mutation in any one of these proteins and causes RBC transformation into spherocytes that are ingested by splenic macrophages, leading to anemia, jaundice and splenomegaly

Question 9

What is erythroblastosis fetalis?

Answer 9

• Rh neg mother with Rh pos baby
• First time this occurs, at delivery, blood from fetus mixes with blood from mother and causes mother’s immune system to form antibodies against Rh
• First born Rh pos baby is unaffected, but subsequent Rh pos pregnancies will not. RBCs are hemolyzed.
• Prevention=mother receives Rho-GAM just before birth and after birth of first Rh+ baby

Question 10

What are Howell-Jolly bodies?

Answer 10

• Basophillic nuclear fragments in cytoplasm of RBCs. These are removed by macrophages. Seen in pts with severe hemolytic anemia, dysfunctional spleens or after splenectomy

Question 11

What are Heinz bodies?

Answer 11

• Inclusion of damaged Hb in RBCs as a result of oxidative damage (d/t infections) seen in pts with G6PD deficiency.
• Macrophages remove these bodies forming bite cells

Question 12

What are the precursors to RBCs? Histological difference? What does reticulocytosis indicate?

Answer 12

• Reticulocytes
• Cytoplasm has specks of basophilia due to clusters of ribosomes as some Hb synthesis is occurring
• Increase in reticulocytes indicates body has demand for oxygen that is currently not being fully met (hemorrhage, recent ascent to higher altitude etc.)

Question 13

Describe histological features of neutrophils (aka PMNs)

Answer 13

• Immature neutrophils have nucleis that are band/rod-shaped, therefore called band cells
• Mature neutrophils have lobated nuclei (3-5 lobes)
• Specific (secondary) granules appear light pink and contain antimicrobial enzymes
• Azurophilic (primary) granules represent lysosomes
• Tertiary granules contain enzymes to degrade basal lamina and elements of ECM
• Döhle body: dilated rER, seen in infections and some other conditions

Question 14

Clinical significance of increase in band cells

Answer 14

• Known as shift to the left

- Elevated neutrophil count with shift to the left = acute bacterial infection

Question 15

Histological features of eosinophils

Answer 15

• Bilobed nucleus
• Specific (secondary) granules stain dark pink to red contain substances highly effective in destroying parasites
• Azurophilic (primary) granules are lysosomes that helps destroy parasites and to phagocytose ag:ab complex

Question 16

Histological features of basophils

Answer 16

• S-shaped nuclei obscured by basophilic granules
• Specific granules stain dark blue and contain histamine, heparine, eosinophilic chemotaxic factor etc.
• Azurophilic granules are lysosomes

Question 17

Order of abundance of leukocytes:

Answer 17

• NLMEB (except lymphocytes > neutrophils in children less than 8)

Question 18

Histological features of lymphocytes

Answer 18

• Narrow rim of basophilic cytoplasm
• Possess narrow rim of basophilic cytoplasm, nucleus is prominent
• Azurophilic granules = lysosomes
• Three types = B, T and NK cells

Question 19

Histological features of monocytes

Answer 19

• Large nucleus, typically described as kidney-shaped
• Cytoplasm is blue-gray
• Azurophilic granules = lysomes = abundant

Question 20

What can elevation to neutrophil count mean?

Answer 20

• Bacterial infection

Question 21

What can elevation to eosinophil levels mean?

Answer 21

• Allergic reactions, IB disease, parasitic infestation

Question 22

What can decrease to basophil levels mean?

Answer 22

• Decreased in acute allergic reactions

Question 23

What can increase in lymphocyte levels mean?

Answer 23

• Elevated in viral infections

Question 24

Conditions that elevate RBC count? Decrease count?

Answer 24

1. ) Elevate
   - Decreased oxygenation, renal cell carcinoma, hepatocellular carcinoma, decreased plasma volume
2. ) Decrease
   - Aplastic anemia, hemolytic anemia, pernicious anemia, disruption of myeloid tissue (cancer, radiation)

Question 25

Conditions that elevate neutrophil count? Decrease count?

Answer 25

1. ) Elevate - Acute bacterial infections, inflammatory processes, physical stress, tissue necrosis, granulocytic leukemia 2. ) Decrease - typhoid fever, brucellosis, viral infections, massive infection, drugs

Question 26

Conditions that elevate eosinophil count? Decrease count?

Answer 26

1. ) Elevate - Allergic reactions, inflammatory bowel disease, parasitic infestation 2. ) Decrease - corticosteroid use

Question 27

Conditions that elevate basophil count? Decrease count?

Answer 27

1. ) Elevate - Hodgkin’s lymphoma, inflammatory bowel disease, hypothyroidism 2. ) Decrease - Corticosteroid use, acute allergic reactions, hyperthyroidism

Question 28

Conditions that elevate lymphocyte count? Decrease count?

Answer 28

1. ) Elevate - Viral infections, TB, lymphocytic leukemia (common cause of significant elevation) 2. ) Decrease - HIV, corticosteroid and other immunosuppressive drug use

Question 29

Conditions that elevate monocyte count? Decrease count?

Answer 29

1. ) Elevate - Inflammation, TB, malaria, RM spotted fever, monocytic leukemia, chronic ulcerative colitis, regional enteritis 2. ) Decrease - rare

Question 30

Conditions that elevate platelet count? Decrease count?

Answer 30

1. ) Elevate - splenectomy, cancer, stress, exercise, iron deficiency, chronic inflammation 2. ) Decrease - aplastic anemia, leukemia, metastasis to bone marrow, viral infections, antineoplastic agents/chemo, splenic sequestration (hypersplenism)