Bone Marrow Flashcards
What are the three categories of the stromal compartment?
Mesenchymal stem cells, Haemopoietic stem cells, Endothelial-like cells
Mesenchymal stem cells give rise to osteoblasts, adipocytes, and fibroblasts. Haemopoietic stem cells include monocyte-macrophages and osteoclasts.
What is the most common site for bone marrow aspiration?
Posterior superior iliac crest/spine
Other sites include anterior superior iliac crest, sternum, and tibia in infants and young children.
What are the indications for bone marrow aspiration?
Diagnosis, staging of disease, therapeutic monitoring, rule out infections, rule out bone marrow infiltration
Examples include lymphoma, tuberculosis, and metastatic carcinomas.
Fill in the blank: The function of the bone marrow includes _______.
Formation of blood cells, acts as a reservoir for blood cells, osteogenic function, connective tissue function
It also has reticulo-endothelial cell function.
What are the common types of bone marrow needles?
Jamshidi needle, Salah bone marrow aspiration needle, Islam bone marrow needle, Klima sternal needle, Watherfield iliac crest needle
True or False: Yellow bone marrow is actively involved in the formation of blood cells.
False
Yellow marrow consists primarily of fat cells and is not actively engaged in blood cell formation.
What is the primary type of hematopoietic tissue found in red bone marrow?
Haematopoietic stem cells (HSC)
Red marrow is composed of blood vessels, fat cells, and a large number of mature, immature, and primitive haematopoietic cells.
What are the major types of bone marrow?
Red marrow, yellow marrow
What is the role of mesenchymal cells in the bone marrow?
They form the cellular stroma and lay down a rich carpet of extracellular matrix proteins
Examples include proteoglycans, hyaluronate, and collagens.
What are haematopoietic growth factors?
Cytokines that affect self-renewal, differentiation, and adhesion of HSCs and HPCs
Examples include stem cell factor, granulocyte colony-stimulating factor, erythropoietin.
What cell surface markers can be used to identify haematopoietic stem cells (HSC)?
CD34+, CD38-, CD90+, CD45R-
Fill in the blank: Fat cells replace haemopoietic cells in the bones of the hand, feet, legs, and arms, leading to the formation of _______.
Yellow marrow
What are the dominant anatomical sites of haemopoiesis during early development?
Yolk sac and fetal liver
These sites contain cells with multilineage differentiation capabilities.
What is the principal function of the non-haemopoietic cells in the bone marrow?
They synthesize factors that activate haematopoietic stem cells (HSCs)
These include soluble and insoluble factors.
What is the structure of the bone marrow?
Hematopoietic tissue islands and adipose cells surrounded by vascular sinuses interspersed within a meshwork of trabecular bone.
What is the composition of the bone marrow?
Haemopoietic cells, marrow adipose tissue, supportive stromal cells
It is a soft, gelatinous, highly vascular, and flexible connective tissue.
What factors contribute to the fate of haematopoietic stem cells?
Non-haemopoietic cells
These cells play an important role in regulating HSCs through various factors.
What are the components of the normal bone marrow?
Bone stroma, haematopoietic tissue, other cells
Haematopoietic tissue includes erythroid, granulocytic, megakaryocytic cells.
What is the blood supply to the bone marrow composed of?
Periosteal artery, central vein, nutrient artery, periosteal capillaries, bone marrow sinuses.
What happens to yellow marrow in cases of prolonged demand for blood cell production?
It can revert to haemopoietically active marrow.
True or False: A common function of the bone marrow is serving as a reservoir for blood cells.
True
What are the main sources of blood supply to the bone?
Nutrient artery and periosteal capillaries
The nutrient artery is the primary source, entering the nutrient canal of the bone.
What is the function of the nutrient artery in the bone?
It bifurcates into ascending and descending medullary arteries, supplying blood to the inner cortex
Radial branches travel towards the inner face of the cortex.
What type of network do cortical capillaries form after reentering the marrow cavity?
Sinusoidal network
This network is involved in the blood flow within the bone marrow.
How does blood flow in the bone marrow compare to other organs?
It is analogous to that in the spleen and kidney
This highlights the unique vascular structure of the bone marrow.
What does the marrow stroma consist of?
A network of sinuses originating from cortical capillaries
The sinuses terminate in collecting vessels that enter systemic venous circulation.
What is the composition of the sinus wall in the marrow?
Trilaminar in nature, composed of:
* Luminal layer of endothelial cells
* Abluminal coat of adventitial reticular cells
* Thin basement membrane
This structure supports the function of the marrow.
Where does haemopoiesis occur within the bone marrow?
In the extravascular space between marrow sinuses (intersinus spaces)
This process is regulated by cytokines and extracellular matrix components.
What regulates vessel tone in the bone marrow?
Myelinated and non-myelinated nerve fibers present in periarterial sheaths
Non-myelinated fibers also terminate in marrow spaces.
What is the neuroreticular complex?
An anatomical unit consisting of efferent nerve and marrow stromal cells connected by gap junctions
This complex facilitates communication between sympathetic nerves and marrow elements.
True or False: The endothelial and adventitial cells are sources of haemopoietic cytokines.
True
These cells play a critical role in regulating blood cell formation.
Fill in the blank: The sinus wall has a thin _______ membrane present between the cell layers.
basement
This membrane is underdeveloped and contributes to the trilaminar structure.
