Erythropoiesis Flashcards
What is erythropoiesis?
The process of producing red blood cells (erythrocytes) from progenitor cells in the bone marrow.
Where does erythropoiesis primarily occur in adults?
In the bone marrow.
True or False: Erythropoiesis can occur in the liver and spleen in adults.
False.
What hormone stimulates erythropoiesis?
Erythropoietin (EPO).
Fill in the blank: Erythropoietin is primarily produced by the _____ in response to low oxygen levels.
kidneys.
What are the stages of erythropoiesis?
Hemapoietic stem cell
Common myeloid progenitor
Erythroid burst forming unit
Colony forming unit
Proerythroblast
Basophilic erythroblast
Polychromatic erythroblast
Normoblast
Reticulocyte
Erythrocyte.
Which stage of erythropoiesis is characterized by the loss of the nucleus?
Normoblast
True or False: Reticulocytes are immature red blood cells.
True.
What is the lifespan of a typical erythrocyte?
Approximately 120 days.
Which vitamin is essential for erythropoiesis?
Vitamin B12.
What mineral is vital for hemoglobin synthesis during erythropoiesis?
Iron.
Fill in the blank: Erythropoiesis is regulated by the _____ feedback mechanism.
negative.
What is the role of macrophages in erythropoiesis?
To phagocytize old or damaged erythrocytes, recycling iron and other components.
True or False: Erythropoiesis is unaffected by altitude.
False.
What does the term ‘anemia’ refer to?
A condition characterized by a deficiency of red blood cells or hemoglobin.
Which condition can stimulate increased erythropoiesis?
Chronic hypoxia.
What is the significance of the erythropoietin receptor?
It mediates the effects of erythropoietin on erythroid progenitor cells.
Fill in the blank: The process of erythropoiesis is influenced by levels of _____ in the blood.
oxygen.
True or False: Erythropoiesis can be influenced by hormones other than erythropoietin.
True.
What role does folate play in erythropoiesis?
It is essential for DNA synthesis and cell division.
What is the main characteristic of a reticulocyte?
It contains residual RNA and is the last stage before becoming a mature erythrocyte.
Fill in the blank: The average number of erythrocytes in a microliter of blood is approximately _____ million.
5.
True or False: Erythrocytes are produced continuously throughout a person’s life.
True.
What is the effect of testosterone on erythropoiesis?
It stimulates erythropoietin production and enhances erythropoiesis.
What is the primary site of erythropoiesis during fetal development?
The liver.
Fill in the blank: The process of erythropoiesis is crucial for maintaining _____ levels in the body.
oxygen.
True or False: Erythropoiesis can be inhibited by high oxygen levels.
True.
What are erythrocytes primarily composed of?
Hemoglobin.
What effect does chronic inflammation have on erythropoiesis?
Negatively effects it, can lead to anemia
Fill in the blank: Erythropoiesis can be measured by the _____ count.
Reticulocyte.
True or False: Hemoglobin levels are a direct indicator of effective erythropoiesis.
True.
What is the role of the spleen in erythropoiesis?
It acts as a reservoir for erythrocytes and removes old or damaged cells from circulation.
What is the purpose of a complete blood count (CBC) in relation to erythropoiesis?
To assess red blood cell levels and evaluate erythropoiesis.
Fill in the blank: Erythropoiesis is part of the larger process of _____ production.
hematopoiesis.
True or False: Erythropoiesis can be artificially stimulated by certain medications.
True.
What is the importance of maintaining adequate iron levels for erythropoiesis?
Iron is a critical component of hemoglobin, which is necessary for oxygen transport.
Which type of anemia is characterized by insufficient iron?
Iron deficiency anemia.
What is the primary role of erythrocyte membrane proteins?
To maintain cell shape and flexibility.
True or False: Erythrocytes have a nucleus.
False.
What can lead to increased erythropoiesis?
Living at high altitudes.
What is the role of interleukin-3 (IL-3) in erythropoiesis?
It supports the growth and differentiation of hematopoietic stem cells.
Fill in the blank: The erythropoiesis process is influenced by various _____ and growth factors.
cytokines.
True or False: Erythropoiesis is a strictly regulated process.
True.
What is the consequence of impaired erythropoiesis?
Anemia or reduced oxygen-carrying capacity of the blood.
Which conditions is associated with increased erythropoiesis?
Dehydration.
Fill in the blank: Erythropoiesis is essential for maintaining _____ homeostasis.
oxygen.
What is the role of the bone marrow microenvironment in erythropoiesis?
It provides support and signals necessary for the growth and maturation of erythroid progenitor cells.
Physiological value of reticulocytes
1-2%
What can change the physiological value of reticulocytes?
Iron supplements taken to treat anemia (value increases)
Which stem cell pool does erythropoiesis start from?
Hemopoietic stem cells -> myeloid stem cells
Which are the erythroid progenitor cells?
BFU-E
CFU-E
Which are the erythroid precursor cells?
Pronormoblast
Basophillic erythroblast
Polychromatophillic erythroblast
Normoblast
Reticulocyte
How many CFU-E does 1 BFU-E produce?
2^6 (64)
How many erythrocytes does 1 CFU-E produce?
2^6 (64)
How many erythrocytes does 1 BFU-E produce?
2^12
Which has the highest affinity receptor for EPO, CFU-E or BFU-E?
CFU-E
How many times higher does the concentration of EPO need to be to stimulate BFU-E?
10 times
What induces the EPO expression in kidneys?
Hypoxia
What produces EPO?
Pericytes in the kidneys
Where is the sensor of level oxygen found?
In the kidneys
Different name for EPO
Hemopoietin
Erythrocyte stimulating factor
Sites of erythropoiesis
Fetal Life → Yolk sac → Liver/spleen → Bone marrow.
Postnatally → Bone marrow (vertebrae, ribs, sternum, pelvis).
How long does the process take?
5-7 days
What does kidneys use to detect hypoxia?
HIF-1 (hypoxia inducing factor)
Cytokines that suppresses erythropoiesis
TNF-ALPHA
IFN-GAMMA
IL-1
What mutation can lead to uncontrolled erythropoiesis?
JAK2 point mutation
What can EPO be used to improve?
Performance in sports, used for doping
What is normoxia
normal levels of oxygen
What is the regulatory feedback loop of erythropoiesis?
Hypoxia → HIF-1alpha → More EPO
EPO → Erythropoiesis → Erythrocyte formation
Erythrocytes → Normoxia → less EPO
3 conditions of normoxia
1: Pro-402 and pro-564 of the HIF-1alpha subunit are hydroxylated and propel-hydroxylase
2: Hydroxylated protein is bound to von Hippel-lindau factor (VHL) → protein that acts as a ubiquitin ligase for HIF-1alpha causing polybiquitination
3: HIF-1alpha is degenerated
2 conditions of hypoxia
1: HIF-1alpha is no longer hydroxylated and stable
2: Associates with HIF-1beta and promotes transcription
