Introduction and Overview of Hematology

Question 1

Explain what hematocrit is and how it is measured

Answer 1

Hematocrit: proportion of blood by volume made up of red blood cells, value determined by measuring the length of the RBC layer and dividing it by the total length of the column of blood (RBCs+buffy coat+plasma), always reported as percentage

Question 2

describe the basic shape of an erythrocyte and what the shape allows

Answer 2

Biconcave disc shape:

i. Increases SA to volume ratio by 40% (compared to sphere) for greater gas exchange
ii. Allows RBC to squeeze through tight places (sphere shape can’t compress like a biconcave disc) and RBCs are on average 25% wider than capillaries they travel.
iii. Move through vessel easier with this shape

Question 3

Describe the composition of an erythrocyte

Answer 3

b. Lacks nucleus: nucleus present in bone marrow, but then removed when it goes out into blood stream.
c. Lacks mitochondria: they have these organelles in the bone marrow but lose them prior to being released into periphery, therefore RBCs required anaerobic glycolysis.
d. Contains lots of hemoglobin, thus, a major function of RBC is to transport O2 from lungs to tissue, hemoglobin also makes RBCs and blood red.
e. Membrane is highly elastic allow cell to deform while maintaining structural integrity. Has 2-D elastic network of cytoskeletal proteins that are tethered to sites on cytoplasmic domains to transmembrane proteins embedded in the plasma membrane.

Question 4

Define Hematopoiesis:

Answer 4

formation of blood cellular components

Question 5

Define Erythropoiesis:

Answer 5

process by which RBCs are produced

Question 6

Define hemolysis:

Answer 6

rupturing of erythrocytes and release of their contents (hemoglobin)

Question 7

Define hemostasis:

Answer 7

the arrest/stopping of bleeding

Question 8

Define Thrombosis:

Answer 8

formation of a blood clot inside a blood vessel that obstructs the flow of blood

Question 9

5 types of white blood cells in the blood

Answer 9

Lymphocytes, Neutrophils, Monocytes, Eosinophils, Basophils

Question 10

Explain (1) what platelets are, (2) where they come from, and (3) what their basic function is

Answer 10

Platelets, thrombocytes, (1) are small cell fragments (2) produced from large cells in the bone marrow called megakaryocytes. 1 megakaryocyte=5000 platelets. (3) Responsible for hemostasis (stop bleeding). Hemostasis results from interaction between platelets, endothelium and blood coagulation factors

Question 11

Compare and contrast acute leukemia vs chronic leukemia

Answer 11

• Acute: cells are immature in their degree of differentiation and that clinical course is usually rapid without intervention
• Chronic: cells are more mature in their differentiation and the disease follows a more indolent clinical course.

Question 12

Compare and contrast leukemia vs lymphoma

Answer 12

• Leukemia: cancer cells in blood and bone marrow

- Lymphoma: cancer cells predominantly outside of the bone marrow/blood

Question 13

Compare and contrast lymphoid leukemia vs myeloid leukemia

Answer 13

• Lymphoid: arising from lymphocytic lineage

- Myeloid: arising from one of the other cell types in the marrow