L7 Hematopoiesis and Bone Marrow Flashcards
What are the primary lymphoid organs ?
- Thymus
- Bone Marrow
- Gut-associated lymphatic tissue
How do the lymphocytes travel ?
via blood vessels and lymphatics vessels to secondary lymphoid organs and tissues
What are the secondary lymphoid organs and tissues?
- Diffuse Lymphatics Tissue
- Lymphatic Nodules and Tonsils
- Lymph Nodes
- Spleen
Where are developing blood cells ?
- bone marrow
Where are the mature blood cells ?
- blood
Hemopoiesis
formation of blood cells and platelets
During fetal life blood cells, how often is the hematopoiesis happening ?
- formed in several organs
How often does the hemopoiesis after birth ?
- occurs only in the red bone marrow and lymphatic tissues
What is the 1st Phase, Embryonic Yolk Sac ?
Formation of blood islands ( red blood cells)
What is the 2nd Phase, Hepatic ?
Red and some white blood cells
What is the 3rd Phase, Bone Marrow ?
Red and white blood cells, also spleen, lymphatic organs
What are the two types of marrow ?
- red and yellow
Red Marrow consists of
- stroma ( reticular cells) that produce fibers
- blood-forming cords
- endothelial-lined sinusoids
What color are all marrow in newborns?
- red
Where is the inactive marrow ?
in the long bones
Where is the active marrow ?
in the spongy parts of the bone
In adults what is formed in the bone marrow ?
erythrocytes, granulocytes, monocytes, and platelets
Where are lymphocytes formed ?
both red bone marrow and in the lymphatic tissues
Yellow marrow
inactive bone marrow
Sinusoid Capillary
mature cells enter here to leave, shows bone marrow
Fenestrated sinusoids endothelial lining with ?
- discontinuous base membrane and incomplete cover by reticular (adventitial cells)
Marrow stromal compartment contains
- fibroblasts and macrophages
Cytokines Production is done by ?
- meshwork of reticular fibers and reticular cells (adventitial cells)
Hemopoietic “Cords”
pockets of developing cells
What happens in the bone marrow aspiration ?
- a needle is inserted through the skin until it penetrates bone
Where the preferred anatomical site of the bone marrow aspiration ?
Hip Bone
How is a small amount of bone marrow obtained by bone marrow aspiration ?
applying negative pressure with a syringe attached to the needle
Intact bone marrow is obtained how ?
- by a small incision in the skin to allow the biopsy needle to pass into the bone
What is the bone marrow core biopsy used for ?
- diagnose and stage different types of cancer or monitor the results of chemotherapy
Megakaryocyte
forming cell
Megakaryoblast
last cell capable of mitosis (endomitosis)
Megakaryocyte
platelets, with a multilobulated nucleus
In the megakaryocyte what is the difference in chromosomes and cytoplasms
- the chromosomes divide
- cytoplasm does not divide
Thrombopoietin
- causes hormonal stimulation
- platelet-producing
What is the erythrocytes movement to sinusoid capillary ?
- use pressure gradient
What is the leukocytes cell movement to sinusoid capillary ?
have motility
What happens to the pressed abluminal plasma and the luminal membrane ?
gets fused
What does the transitory opening allow ?
- passage of cells or processes
What happens to the aperture ?
repaired
In adults where do platelets originate in ?
red bone marrow by fragmentation of the cytoplasm of mature megakaryocytes
Where does the RBC’s develop from?
multipotential myeloid stem cells in bone
What is the development of the RBC’s influenced by ?
Erythropoietin and some cytokines
What is the basic process of RBC maturation ?
- synthesis of hemoglobin
- formation of an enucleated, biconcave small corpuscle
What are the major changes during the process of maturation?
- cell volume decreases
- Nucleoli diminish in size
- nuclear diameter decreases
- Chromatin becomes increasingly dense
- Thickened and reduced in size
What happens when there is maturation of erythrocytes ?
the cytoplasmic basophilia (ribosomes) decreases, while acidophilia (hemoglobin) simultaneously increases
What happens to the cytoplasm when going from proerythroblast to erythrocytes ?
- continuous increase in cytoplasmic hemoglobin concentration
What happens to the nuclear volume when going from proerythroblast to erythrocytes ?
- gradual decrease in nuclear volume
What happens to the chromatin condensation when going from proerythroblast to erythrocytes ?
increase
Reticulocyte
still an immature erythrocyte
- that will loose its mitochondria and ribosomes
What happens when the nucleated RBC are seen on adult’s peripheral blood smear ?
suggests that there is a very high demand for the bone marrow to produce RBCs
What could be the pathologic causes if there is an increase amount of reticulocytes and less erythrocytes ?
- Anemia, Thalassemia, Miliary, Tuberculosis, cancers and chronic hypoxemia
Myeloblast
large cell, euchromatic nucleus; large nuclear-to-cytoplasm volume
Promyelocyte
large cell, large nucleus; cytoplasm: large blue/black azurophilic granules produced only in this stage
Myelocyte
development of a specific cytoplasmic granules, nucleus flatted on one side
Metamyelocyte
smaller cell, more heterochromatin
- more specific neutrophilic granules
When is the band form seen?
in the neutrophilic series
Neutrophilic Myelocyte
- accumulation of specific granules occurs
- first site of development of a specific type of Granulocyte series ( neutrophilic, eosinophils, or basophilic)
Where monocytes produced ?
bone marrow from a bipotential stem cell
What does the monocytes differentiate into ?
macrophages
What are lymphocytes derived from ?
- multipotential lymphoid stem cells
Lymphocyte maturation
- nuclear chromatin becomes more compact
- cells decrease in size
Anaplastic Anemia
pancytopenia, reduction in the number of erythrocytes, all white blood cells, and platelets in blood circulation
Hypocellular Bone Marrow
consists largely of adipose tissue
What is the treatment for anaplastic anemia ?
- bone marrow transplantation
