Qq Flashcards
(47 cards)
What is the primary function of red blood cells (erythrocytes)?
Carriage of oxygen by haemoglobin
Red blood cells are specialized for efficient oxygen transport.
What modifications allow red blood cells to facilitate oxygen passage?
Modified membrane and uncluttered cytoplasm
This allows for free and easy passage of oxygen in and out of the cell.
What is the consequence of red blood cells’ modifications?
Inability to regenerate or produce proteins efficiently
Unlike nucleated cells, red blood cells have limited regenerative capabilities.
What are the stages of haemopoietic cell differentiation?
- Haematopoietic Stem Cells
- Progenitor Cells
- Precursor (Maturing) Cells
- Mature (circulating) Blood Cells
Each stage has distinct characteristics and functions.
What percentage of total nucleated haematopoietic cells are progenitor cells?
3%
Progenitor cells are the first differentiation of stem cells.
What are the two types of common progenitor cells?
- Common Myeloid Progenitor cell
- Common Lymphoid Progenitor cell
CMP can become any type of blood cell except lymphocytes; CLP become lymphocytes.
What types of cells can the Common Lymphoid Progenitor (CLP) cells differentiate into?
- T-Cells / T-Lymphocytes
- B-Cells / B-Lymphocytes
- Natural Killer (NK)-Cells / NK-Lymphocytes
These are critical components of the immune system.
What types of cells can the Common Myeloid Progenitor (CMP) cells differentiate into?
- Neutrophils
- Eosinophils
- Basophils
- Monocytes/Macrophages
- Erythrocytes
- Thrombocytes
CMP cells give rise to various blood cell lineages.
What is erythropoiesis?
The complex and finely regulated process of red blood cell formation
Erythropoiesis occurs in various sites including red bone marrow.
What is the estimated daily production of erythrocytes in a healthy person?
Approximately 10^12 new erythrocytes
This high production rate is crucial for maintaining oxygen transport.
What role do bone marrow macrophages play in erythropoiesis?
Provide cytokines and signals crucial for erythropoiesis
They promote maturation and proliferation of proerythroblasts.
What are erythroblastic islands?
Niches for erythropoiesis where several stages occur
They are important for the maturation of red blood cells.
What is the significance of adhesion molecules in erythropoiesis?
Promote close physical proximity of macrophages and red cell precursors
This interaction is crucial for effective erythropoiesis.
What are the stages of normoblast maturation?
- Pronormoblast
- Basophilic normoblast
- Polychromatic normoblast
- Orthochromatic normoblast
- Reticulocyte
- Mature RBC
Each stage reflects a progressive maturation process.
What are the requirements for erythropoiesis?
- Erythropoietin
- Iron or cobalt
- Vitamins (B12, folate, C, E, B6, thiamine, riboflavin)
- Hormones (Thyroxine, Androgens)
Deficiencies in these factors may lead to anemia.
What is erythropoietin (Epo)?
Primary regulator of erythropoiesis
It is a heavily glycosylated polypeptide produced mainly by the kidneys.
What stimulates the production of erythropoietin?
O2 tension in the tissues of the kidney
Low oxygen levels lead to increased Epo production.
What is the function of transcription factors GATA-1 and GATA-2 in erythropoiesis?
Initiate erythroid differentiation and enhance expression of erythroid-specific genes
They are activated by erythropoietin receptor stimulation.
What are the different globin genes involved in hemoglobin synthesis?
- Alpha (α) and Zeta (ζ) on chromosome 16
- Beta (β), Delta (δ), Epsilon (ε), and Gamma (γ) on chromosome 11
These genes code for different globin chains that combine to form hemoglobin.
What is the molecular weight of Hb A?
68,000 daltons
Hb A is the dominant hemoglobin type in adult blood.
What is the composition of adult hemoglobin A (HbA)?
Alpha2Beta2 (α2β2) globin chains
HbA comprises 96-98% of total adult hemoglobin.
What does the hemoglobin-oxygen dissociation curve represent?
The relationship between O2 concentration and the percentage saturation of Hb with oxygen
This curve helps understand how oxygen is transported in the blood.
What does P50 represent in the hemoglobin-oxygen dissociation curve?
Partial pressure of O2 at which Hb is 50% saturated with oxygen
Normal P50 is 26.6 mmHg.
What happens to the hemoglobin-oxygen dissociation curve with increased affinity for oxygen?
The curve shifts to the left
This indicates that hemoglobin holds onto oxygen more tightly.
