Blood and Cellular Science Flashcards
What distinguishes constitutive haematopoiesis from inducible haematopoiesis?
Constitutive haematopoiesis is the normal generation of immune cells, while inducible haematopoiesis refers to increased production during stress.
At what sites does haematopoiesis occur during fetal development?
0-2 months in the yolk sac, 2-7 months in the liver and spleen, and 5-9 months in the bone marrow.
What is the significance of vascular sinuses in bone marrow?
They allow mature blood cells to enter the bloodstream.
Why is the marrow-blood barrier significant in bone marrow function?
It retains immature blood cells within the bone marrow until they mature.
How many mature blood cells can one stem cell produce after multiple divisions?
One stem cell can produce up to 1 million mature blood cells after 20 cell divisions.
What is the role of cell adhesion molecules in haematopoiesis?
They attach immature blood cells to stromal cells in the bone marrow.
What are the functions of extracellular molecules secreted by stromal cells?
They form an extracellular matrix and secrete growth factors that support cell attachment and differentiation.
How does the site of haematopoiesis change from infancy to adulthood?
In infants, it occurs in the bone marrow of practically all bones; in adults, it occurs in specific bones like the vertebrae, ribs, sternum, skull, sacrum, pelvis, and femur.
What are the two types of bone marrow, and how do they differ?
Red (haematogenous) bone marrow, involved in blood cell production, and yellow bone marrow, containing more fat.
What types of cells arise from pluripotent hematopoietic stem cells?
All blood cells, including erythrocytes, leucocytes, and platelets.
What is the role of pluripotent stem cells in haematopoiesis?
They are capable of self-renewal and can differentiate into various blood cell types.
How are maturing blood cells attached to stromal cells in the bone marrow?
Through multiple cell adhesion molecules facilitating their retention during maturation.
What is haematopoiesis and why is it important?
Haematopoiesis is the process of blood cell formation, crucial for producing cells necessary for oxygen transport, immune response, and overall bodily function.
What are the potential consequences of a breakdown of the marrow-blood barrier?
It can result in the release of immature cells into the blood, associated with conditions like leukaemia.
What are the primary components transported by the blood?
Oxygen, carbon dioxide, food molecules (glucose, lipids, amino acids), ions (e.g., Na+, Ca2+, HCO3-), waste products (e.g., urea), hormones, and heat.
How do mature blood cells exit the bone marrow into circulation?
Only mature blood cells can pass through blood vessel endothelium due to necessary membrane proteins.
How many cells does the bone marrow produce approximately every second?
Approximately 3 million cells.
What is the structure and function of bone marrow?
Bone marrow is soft, pulpy tissue that fills bone cavities, containing blood vessels and blood-producing cells.
What percentage of an adult’s body weight is attributed to blood volume?
7% of body weight, or 8% including the bone marrow.
What are the cellular components of blood?
Erythrocytes (red blood cells), leucocytes (white blood cells), and platelets.
Why is the bone marrow stroma important for haematopoiesis?
It creates a suitable environment for stem cell growth and development.
What types of growth factors are involved in regulating haematopoiesis?
Glycoproteins produced by stroma that promote proliferation, differentiation, and maturation of blood cells.
What is a bone marrow aspiration, and what information does it provide?
A procedure to obtain a sample for morphological analysis and cell line proportions.
What conditions can lead to the secretion of erythropoietin?
Low RBC count, hemorrhage, high altitude, prolonged heart failure, and lung disease.
