Bone marrow Flashcards
Hemopoiesis (5)
Erythropoiesis
Granulopoiesis
Monocytopoiesis
Lymphopoiesis
Thrombocytopoiesis
Hemopoiesis, or blood cell formation, first occurs in a_________ cell population of the embryonic______
mesodermal
yolk sac
Hemopoiesis:
Shifts during second trimester mainly to the developing_____, before becoming concentrated in newly formed bones during the last 2 months of gestation.
liver - major
Spleen - minor
Hemopoietic bone marrow occurs in many locations through puberty, but then becomes increasingly restricted to components of the_____________.
axial skeleton
Hemopoietic bone marrow occurs in many locations through puberty, but then becomes increasingly restricted to components of the___________
axial skeleton
are pluripotent cells capable of asymmetric division and self-renewal.
Stem cells
T or F| ALL blood cells arise from a single major type of pluripotent stem cell in the bone marrow that can give rise to all the blood cell types.
True
2 major lineages of progenitor cells with restricted potentials:
lymphoid cells (lymphocytes)
myeloid cells
Myeloid cells - include:
granulocytes
monocytes
erythrocytes
megakaryocytes
- migrate from the bone marrow to the thymus or the lymph nodes, spleen, and other lymphoid structures, where they proliferate and differentiate.
Lymphoid progenitor cells
Progenitor cells for blood cells are commonly called
colony-forming units (CFUs)
4 major types of progenitor cells
Erythroid lineage of CFU-erythrocytes (CFU-E)
Thrombocytic lineage of CFUmegakaryocytes(CFU-Meg)
Granulocyte-monocyte lineage of CFUgranulocytes-monocytes (CFU-GM)
Lymphoid lineage of CFU-lymphocytes of all types (CFU-L)
cannot be morphologically distinguished and simply resemble large lymphocytes
Stem and progenitor cells
Has greatest potentiality
Stem cell
Greatest mitotic activity
Precursor cells (blasts)
Greatest typical morphologic characteristics
Mature cells
Greatest self-renewing capacity
Stem cells
Greatest influence of growth factors
Progenitor cells
Precursor cells (blasts)
Greatest differentiated functional activity
Mature cells
Hemopoietic growth factors or ________ or ________
colony- stimulating factors (CSF) or
cytokines
glycoproteins that stimulate proliferation of progenitor and precursor cells and promote cell differentiation and maturation within specific lineages
Hemopoietic growth factors or colony- stimulating factors (CSF) or cytokines
Bone marrow:
Blood-forming_______
_________ - filled with adipocytes that exclude most hemopoietic cells
Red bone marrow
Yellow bone marrow
MATURATION OF ERYTHROCYTES
Several major changes take place during erythropoiesis:
Cell and nuclear volumes decrease
Nucleoli diminish in size and disappear
Chromatin density increases until the nucleus presents a pyknotic appearance and is finally extruded from the cell.
There is a gradual decrease in the number of polyribosomes (basophilia)
Increase in the amount of hemoglobin (a highly eosinophilic protein)
Mitochondria and other organelles gradually disappear
MATURATION OF ERYTHROCYTES
Proerythroblast
Basophilic erythroblast
Polychromatopholic erythroblast
Orthochromatophilic erythroblast
Nucleus ejected
Reticulocyte
Erythrocyte
reticulocytes, which are cells that have lost their nuclei but have not yet completely lost the________ used to synthesize globin, as demonstrated by a stain for RNA. (What is the name of the stain?)
polyribosomes
Brilliant cresyl blue
involves cytoplasmic changes dominated by synthesis of proteins for the azurophilic granules and specific granules.
Granulopoiesis
Granulopoiesis: formation of granules
Myeloblast
Promyelocyte
Myelocyte
Metamyelocyte
Granulopoiesis:
No cytoplasmic granules
Myeloblast
Granulopoiesis:
First azurophilic granules being secreted in Golgi apparatus
Promyelocyte
Granulopoiesis:
Moderate number of azurophilic granules and initial production of specific granules in Golgi zone
Myelocyte
Granulopoiesis:
Abundant specific granules and dispersed azurophilic granules;
Golgi apparatus reduced
Metamyelocyte
Granulopoiesis
Typical precursor cells shown are as follows:
myeloblast (MB);
promyelocyte (1);
myelocytes (2);
late myelocyte (3);
metamyelocytes (4);
band cells (5);
nearly mature segmented neutrophils (6).
Monocytopoiesis
Monoblast
Promonocyte
Monocyte
Monocytopoiesis
Nucleus: Round to oval; may be irregularly shaped
Nucleoli: 1-2; may not be visible
Chromatin: Fine
Cytoplasm: Light blue to gray
Granules: None
Monoblast
Monocytopoiesis
Nucleus: Irregularly shaped; folded; may have brain-like convolutions
Nucleoli: May or may not be visible
Chromatin: Fine to lacy
Cytoplasm: Light blue to gray
Granules: Fine azurophilic
Vacuoles: May be present
Promonocytes
Monocytopoiesis
Nucleus: Variable; may be round, horseshoe shaped; often has folds producing “brainlike” convolutions
Nucleoli: Not visible
Chromatin: Lacy
Cytoplasm: Blue-gray; may have pseudopods
Granules: Many fine granules giving the appearance of ground glass
Vacuoles: Absent to numerous
Monocytes
Lymphopoiesis
Lymphoblast
Prolymphocyte
NK cells
Small lymphocytes
- T lymphocytes
- B lymphocytes
Originate in the red bone marrow by dissociating from mature megakaryocytes
PLATELETS
Platelets
Differentiate from megakaryoblasts in a process driven by_________
thrombopoietin
are giant cells with large, irregularly lobulated polyploid nuclei, coarse chromatin, and no visible nucleoli
Megakaryocytes
Megakaryocytes produce all the characteristic components of platelets and in a complex process extend many long, branching pseudopodia-like projections called__________, from the ends of which platelets are pinched off almost fully formed.
proplatelets
Thrombocytopoiesis
Megakaryoblast
Megakaryocyte
Platelet precursor extensions
Platelets
