Erythropoiesis and Bone Marrow Quiz

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Questions and Answers

What is the primary function of mature erythrocytes?

To transport nutrients from the intestines to cells

To deliver oxygen from the lungs to tissues and cells (correct)

To produce hormones for metabolism

To provide immunity against infections

What is a key morphological feature of mature erythrocytes?

Presence of multiple nuclei

Large size and round shape

Biconcave shape with an anucleated structure (correct)

High content of organelles

How long does it take for proerythroblasts to convert into mature erythrocytes?

10 days

2 days

5 days

7 days (correct)

Which of the following factors is essential for erythropoiesis?

Intrinsic factor of Castle Signup and view all the answers

What happens to organelles during the maturation of erythrocytes?

They disappear Signup and view all the answers

What is the main characteristic of the pronormoblast in terms of hemoglobin synthesis?

No hemoglobin is produced Signup and view all the answers

During which stage does hemoglobin synthesis begin?

Basophilic normoblast Signup and view all the answers

What is the typical N/C ratio of the polychromatic normoblast?

4:1 Signup and view all the answers

Which type of normoblast is characterized by having a small pyknotic nucleus and cannot synthesize DNA?

Orthochromatic normoblast Signup and view all the answers

What does an increase in reticulocyte count indicate?

Enhanced production of red blood cells Signup and view all the answers

What morphological feature can be seen in reticulocytes?

Residual RNA in the cytoplasm Signup and view all the answers

What is the primary function of erythrocytes?

Transport oxygen Signup and view all the answers

What is the significance of monitoring reticulocyte counts in newborns?

To gauge bone marrow activity Signup and view all the answers

What is the primary function of erythropoietin in erythropoiesis?

To stimulate maturation of red blood cell precursors Signup and view all the answers

Which stage of erythropoiesis follows the basophilic normoblast?

Polychromatophilic Normoblast Signup and view all the answers

What significant change occurs to erythroid precursor cells during maturation?

Disappearance of the nucleus Signup and view all the answers

What is the WBC to RBC ratio mentioned in erythropoiesis?

1:500 Signup and view all the answers

What type of cells are derived from pluripotential haematopoietic stem cells?

All types of blood cells Signup and view all the answers

Which of the following is the committed stem cell for erythrocytes?

CFU-E Signup and view all the answers

Why is the reticulocyte significant in the process of erythropoiesis?

They indicate active erythropoiesis when released prematurely Signup and view all the answers

What change in the size of cells is observed from CFU-E to mature erythrocytes?

Decrease from 25 to 7.2 micrometers Signup and view all the answers

Study Notes

Erythropoiesis

Process of red blood cell development from early precursor cells to mature red blood cells.
Erythropoietin is the primary regulator and stimulates red blood cell precursors to mature.
Adult livers and spleens produce RBCs when bone marrow is damaged or fibrosed.

Bone Marrow

Size equivalent to the liver in weight.
Produces blood cells, including 75% leukocytes and 25% erythrocytes.
The ratio of white blood cells to red blood cells is 1:500.
Red blood cells have a shorter life span than white blood cells.

Process of Erythropoiesis

Blood cells originate in the bone marrow from stem cells called pluripotential hematopoietic stem cells (PHSC).
PHSCs are uncommitted and give rise to all blood cells.
A small number of PHSCs remain undifferentiated to maintain the supply of stem cells.
Committed PHSCs develop from uncommitted stem cells and differentiate into specific types of blood cells.

Colony Forming Units (CFU)

CFU-E is a committed stem cell that forms erythrocytes.
CFU-GM forms granulocytes and monocytes (neutrophils, eosinophils, basophils).
CFU-M forms megakaryocytes which develop into platelets.

Changes During Erythropoiesis

CFU-E mature through four stages.
Cells decrease in size from 25 μm to 7.2 μm.
The nucleus and nucleoli disappear.
Hemoglobin production increases.
Cytoplasm staining properties change.

Stages of Maturation

Pronormoblast: The earliest and largest erythrocyte precursor cell with a large round nucleus and deeply blue-staining cytoplasm.
Basophilic Normoblast: Characterized by the beginning of hemoglobin synthesis and a deeply basophilic cytoplasm.
Polychromatic Normoblast: Shows an increased production of hemoglobin, resulting in a blue-gray to pink-gray cytoplasm.
Orthochromatic Normoblast: The last nucleated stage, with a small, dense nucleus and abundant red-orange cytoplasm.
Reticulocyte: An immature red blood cell with residual RNA.
Mature Erythrocyte: A biconcave 6-8 μm disc with a 120-day lifespan. It contains 90% hemoglobin and 10% water.

Mature Erythrocytes

Biconcave shape with a diameter of 7-8 μm.
Anucleated (lacks a nucleus).
Cytoplasm stains pink in color.
Reticular network disappears as the cell matures.
7 days for proerythroblasts to become mature erythrocytes.
5 days for proerythroblasts to become reticulocytes.
2 days for reticulocytes to become mature erythrocytes.

Erythropoiesis Summary

Cell size, nucleus size, and basophilia decrease during maturation.
Organelles disappear, and the nucleus is extruded.
Ribosomes disappear in the transition from reticulocytes to erythrocytes.

Factors Necessary for Erythropoiesis

Classified into three categories:
- General Factors: Erythropoietin, thyroxine, hemopoietic growth factors, and vitamins.
- Maturation Factors: Vitamin B12, intrinsic factor, and folic acid.
- Factors Necessary for Hemoglobin Formation: Iron.

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Description

Test your knowledge on the process of erythropoiesis and the functions of bone marrow. Explore how red blood cells develop, the role of erythropoietin, and the significance of hematopoietic stem cells. This quiz covers key concepts and processes in blood cell formation.