Introduction to Hematology

Question 1

Define Hematopoiesis

Answer 1

The process of a hematopoietic stem cell differentiating along different lines of development to eventually produce all the different types of blood cells.

Question 2

Define Erythropoiesis

Answer 2

Process of making RBCs. Specifically, progenitors become erythroblast precursors, which accumulate Hb, condense their nucleus, decrease their cell size, decrease their mRNA. These form reticulocytes in the bloodstream, which eventually form RBCs.

Question 3

Define Anemia

Answer 3

Decreased red cell mass leading to inadequate oxygen delivery issues. There are lots of causes: not making enough RBCs, destroying RBCs faster than you can make them, and bleeding.

Question 4

Define hemolysis

Answer 4

Breakdown and destruction of RBCs

Question 5

Define Hemostasis

Answer 5

Arrest of bleeding, allows blod to clot in response to damage to a blood vessel.

Question 6

Define Thrombosis

Answer 6

Pathological blood clot, i.e. blood clotting when it shouldn’t.

Question 7

Describe the basic shape and composition of an erythrocyte

Answer 7

Shape: Biconcave disk. Provides 40% more surface area than a sphere w/ the same volume, allowing for increased gas exchange. More importantly, shape allows for RBC to be squeezed into tight spaces in the endotheilium.

Composition: Lack a nucleus, lack mitochondria (though these structures are present in RBC precursors). Contain lots of Hb.

Question 8

List the five types of white blood cells in the blood

Answer 8

Lymphocytes
Neutrophils (AKA polymorphonuclear cells or PMNs)
Monocytes
Eosinophils
Basophils

Question 9

Compare and contrast leukemia vs. lymphoma

Answer 9

Leukemia: malignant cells arise from the bone marrow
Lymphoma: Malignant cells are lymphoid and extramedullar (outside of bone marrow), usually involving lymph nodes or other lymph organs.

Question 10

Compare and contrast acute leukemia vs. chronic leukemia

Answer 10

Acute leukemia: cells are immature in their degree of differentiation; clinical course is usually rapidly progressive without intervention.

Chronic leukemia: Cellsa are more mature in their differentiation; disease follows a more indolent clinical course.

Question 11

Compare and contrast lymphoid leukemia vs. myeloid leukemia

Answer 11

Lymphoid: Arising from lymphocytic origin
Myeloid: Arising from one of the other cell types in the marrow.

Question 12

Platelets

Answer 12

Platelets (aka Thrombocytes) are the cellular component of the blood responsible for hemostasis.

Platelets are small cell fragments produced from large polyploid cells in the marrow called megakaryocytes.

Hemostasis is the result of complex interactions between the platelet, the endothelial lining of blood vessels, and the blood coagulation factors in response to disruption of the endothelium.