Hematopoiesis and Peripheral Blood Flashcards
What is hematopoiesis?
the process by which blood cells are formed
What comes from hematopoietic stem cells?
red blood cells
granulocytes
monocytes
platelets
lymphocytes
What comes from myeloid precursors?
RBCs
platelets
monocytes
neutrophils
eosinophils
basophils
What comes from lymphoid precursors?
NK cells
B cells
T cells
Hematopoiesis locations by age
3-8wks gestation
6-30wks gestation
9-28wks gestation
28wks-onward
Yolk sac
Liver
Spleen
Bone Marrow
Hematopoiesis occurs in bone marrow throughout the skeleton until puberty when it moves where?
vertebra and pelvis, skull, sternum (axillary locations)
What are the components of the bone marrow?
hematopoietc cell compartment with vasculature and stem cells
marrow stromal compartment with fenestrated endothelia, adipocytes for energy and macrophages
hematopoietic growth factors produced by stromal compartment
How is hematopoiesis regulated?
by hematopoietic growth factors
What is the role of Stem Cell Factor (SCF)
produced by fetal tissue and bone marrow
weake stimulator of hematopoiesis
makes stem cells responsive to cytokines
What is the role of IL3?
influences the replication and growth potential of hematopoietic progenitors (myeloid lineage)
What is the role of IL6?
Stimulates megakaryotcutes and neutrophil production
key factor in leukemoid reaction
What is the role of IL2?
What is the effect of IL2 and IL6 together on the lymphoid lineage?
T cell growth factor (lymphoid lineage)
B cell growth factor
What is the role of GM-CSF?
stimulates the formation of all leukocytes and reticulocytes
comparable to G-CSF for increasing neutrophils during neutropenia, but G-CSF is used more often clinically
What is the role of G-CSF?
stimulates and increase in neutrophils
treatment for neutropenia after chemotherapy or bone marrow transplant
produced bny endothelial cells, fibroblasts, and macrophages
What is the role of M-CSF?
Stimulates an increase in monocytes and macrophages
What is the role of erythropoietin (EPO)
Produced in kidney
simulates formation of RBCs
EPO stimulators are used in treatment for anemia
What is the role of TPO?
TPO is produced in the liver
stimulates an increase in megakaryocytes and platelets
TPO receptor agonists are used therapeutically
What are reticulocytes?
What happens to the reticulocyte count in hemolytic anemias where RBCs are destroyed?
enlarged, immature erythrocytes which show a residual netowork of ribosomal material (RER)
increase
What is the evolution of the leukocyte?
myeloblast: basophilic cytoplasm, no granules
promyelocyte: large granules in cytoplasm, nucleoli maybe present
myelocyte: oval nucleus, azurophilic granules, 2’ granules
metamyelocyte: indented nucleus is major feature
What is the evolution of lymphocytes?
B and T lymphoblasts: no cytoplasmic granules
B and T cells: T cells mature in thymus, B cells in bone marrow
Plasma cells (from B cells): eccentrically plcaed nucleus with perinuclear hoff generated from activated B cells in spleen and LN with help of T cells and then travel back to bone marrow
What is the evolution of platelets?
megakaryoblasts: with large oval/kidney nucleus and basophilic cytoplasm
Megakaryocyte: large multilobed nucleus with endomitosis and invaginations of plasma membrane
Platelets: break off from megakaryocyte
What are the three compartments for monocytes/macrohages to live in?
Takes 24 hours to transport among the compartments
stem cell to monoblast in bone marrow
monocyte in blood
macrophage in tissues
(specialized in various tissues)
What is MCV?
What is MCH?
What is MCHC?
What is RPI?
average volume (or size) of RBC
average mass of Hb in RBC
concentration of Hb in a given volume
reticulocyte % based on RBC volume
What is anisocytosis?
What is poikilocytosis?
variation in size and increase in RDW
variation in shape (beta thalassemia)
What does it mean if something is an “absolute neutropenia” as apposed to neutropenia?
refers to the actual number of cells, not a percentage
What are the causes of iron deficient anemia?
dietary lack of iron or decreased absorption (poor diet, cow’s milk in infants)
impaired absorption (sprue, partial gastrectomy-acid increases solubility and uptake)
chronic blood or iron loss (tumor, ulcer, menometrorrhagia, extreme distance running)
What does the blood panel look like in someone with iron deficient anemia?
anisocytosis, poikilocytosis, microcytosis, hypochromia
MCV decreased (microcytosis)
MCH decreased
MCHC decreased (hypochromia)
RBC decreased
Reticulocyte count decreased as erythropoiesis decreases
RDW increased
Histologically, when should iron deficient anemia be suspected?
hypochromic microcytic anemia with elevated RDW but no consistent shape changes in RBC
The laboratory evaluation of enmial begins with what?
then, the anemia is catagorized how?
Then what is is done to confirm the diagnosis?
How are the microcytic anemias separated?
How is iron deficiency anemia separated from beta thal.?
a complete blood count and reticulocyte index
as microcytic, macrocytic, or normocytic based on MCV with or without reticulocytosis
peripheral smear
serum iron level, TIBC, and serum ferritin levels
erythrocyte size-distribution width may be particularly helpful in distinguishing iron deficiency from thalassemia
Which anemias have an elevated reticulocyte count?
sickle cell anemia
G6PD def.
Heriditary spherocytosis
autoimmune hemolytic
paroxysmal nocturnal hemoglobinuria
What is marked erythroid hyperplasia?
anemia caused by increased red cell loss or reduced red cell life span generating elevated reticulocyte counts in the peripheral blood and erythroid hyperplasia in the bone marrow
When do you see nucleated RBCs?
Compensatory Erythropoiesis
- severe anemia
- chronic hypoexmia
Hyposplenism, Asplenia
- sickle cell
- traumatic splenectomy