topic 2 Flashcards
cell death by lethal chemical, biological or physical events
necrosis
programmed cell death regulated by genetic material of cell
apoptosis
Blood cell formation – production and development
hematopoiesis
sole site of effective hematopoiesis in normal adults
bone marrow
These cells are present in the first few hours after an ovum is fertilized
the most versatile type of stem cell, can develop into any human cell type, including development from embryo into fetus.
Totipotential stem cells.
These cells are present several days after fertilization.
can develop into any cell type, except they cannot develop into a fetus.
Pluripotential stem cells
These cells are derived from pluripotent stem cells. They can be found in adults, but they are limited to specific types of cells to form tissues. For example, bone marrow stem cells can produce all types of blood cells, bone cartilage, and adipose (fat) cells.
Multipotential stem cells
These cells are derived from pluripotent stem cells. They can be found in adults, but they are limited to specific types of cells to form tissues. For example, bone marrow stem cells can produce all types of blood cells, bone cartilage, and adipose (fat) cells.
Multipotential stem cells
Appearance of different properties in cells
Differentiation
Appearance of different properties in cells
Differentiation
▶ Cells derived from common precursors take separate routes
▶ Maturation occurs from commitment to fully developed cell
Commitment
Three developmental periods
▶ Mesoblastic ▶ Hepatic
▶ Myeloid
Three developmental periods
▶ Mesoblastic ▶ Hepatic
▶ Myeloid
▶ Blood islands of yolk sac
▶ Primarily RBC production
▶ Embryonic hemoglobin produced
MESOBLASTIC
▶ At 6 weeks cell production in liver
▶ Fetal hemoglobin produced
▶ Spleen, thymus, lymph nodes also active production
HEPATIC
At 5th month Bone Marrow becomes site of cell production Liver & spleen now Extramedullary
Hemoglobin A (α2β2)
MYELOID
▪ Very small group of cells
▪ Multipotential cells that give rise to all lineages of blood cells
▪ High self-renewal ability
▪ Not morphologically distinguishable
▪ Identified by flow cytometry with marker CD34
▪ Supporting research
STEM CELLS
▶ Committed cells to differentiation into cell lines
▶ Described as colony-forming units (CFU)
▶ CFU-GEMM
▶ CFU-GM
▶ CFU-Meg
▶ Population amplified by proliferation
PROGENITOR CELLS
▶ Majority of precursor cells
▶ Recognizable morphologic characteristics
▶ Nomenclature unique for each cell line
MATURING CELLS
Govern precursor cell survival, self-renewal, proliferation,
differentiation
Cytokines
Blood forming tissue located between trabeculae
Major hematopoietic organ
BONE MARROW
▶ Lymphopoietic organ in upper mediastinum
▶ Cortex densely packed with small lymphocytes
▶ Primary purpose
▶ Compartment for maturation of T lymphocytes
▶ Precursor T cells leave the bone marrow and enter the thymus
THYMUS
▶ Upper left quadrant of abdomen
▶ Richly supplied with blood
SPLEEN
▶ Lymph nodes and lymphatic vessels
▶ Nodes remove foreign particles from lymph
▶ Functions
▶ Immune defense
▶ B cell production in germinal centers
LYMPHATIC SYSTEM
Total population of erythrocytes and precursors in peripheral blood and bone marrow
▶ RBC production
▶ RBC release
▶ RBC destruction
▶ Primary signal regulating RBC production is oxygen tension
▶ ⇓ tissue oxygenation due to anemia or pulmonary insufficiency
ERYTHRON
▶ Stimulated by Erythropoietin (EPO), a glycoprotein hormone produced in the kidney
▶ EPO accelerates commitment of pluripotent stem cell to CFU-E and erythroid development
ERYTHROPOIESIS
14-25 um
round to oval nucleus
2 nucleoli
dark blue cytoplasm due to concentration
proerythroblast
10-17 um in diameter
basophilic erythroblast
10-15 um in diameter
polychromatic erythroblast
8-12 um in diameter
orthochromatic erythroblast
7-10um in diameter
polychromatic erythrocyte
6-8 um in diameter
erythrocyte
