Human Biology: Red Blood Cells Quiz

Questions and Answers

What shape do red blood cells take in sickle cell anemia?

Rod-shaped

Sickle-shaped (correct)

Disc-shaped

Cube-shaped

What is the normal diameter range of red blood cells?

1-2 µm

10-12 µm

6-9 µm (correct)

3-5 µm

Which protein plays a significant role in providing flexibility to the red blood cell membrane?

Hemoglobin

Keratin

Collagen

Spectrin (correct)

What is the primary site of red blood cell production in infants?

Bone marrow Signup and view all the answers

What percentage of the red blood cell membrane is made up of proteins?

50% Signup and view all the answers

How long is the typical lifespan of a red blood cell?

120 days Signup and view all the answers

Which of the following describes macrocytic anemia?

RBC size exceeds 9 µm Signup and view all the answers

What does the process of hemopoiesis involve?

Differentiation and maturation of stem cells Signup and view all the answers

What is the characteristic of the nucleus in a proerythroblast?

Active and basophilic Signup and view all the answers

Which type of erythroblast exhibits both basophilia and acidophilia?

Polychromatophilic erythroblast Signup and view all the answers

At what stage do erythroblasts start to lose their nucleus?

Orthochromatophilic erythroblast Signup and view all the answers

How are reticulocytes characterized in terms of nucleus presence?

Extruded nucleus Signup and view all the answers

What is the primary feature of mature erythrocytes?

Acidophilic with a pale center Signup and view all the answers

What happens to the proportion of reticulocytes in the blood during severe erythrocyte loss?

Increases due to elevated production Signup and view all the answers

Which erythroblast stage is characterized by a gradual reduction in size?

Polychromatophilic erythroblast Signup and view all the answers

What feature distinguishes reticulocytes from mature erythrocytes?

Mitochondria and ribosomal reticulum Signup and view all the answers

What is the primary function of the biconcave shape of red blood cells (RBCs)?

To provide greater surface area for gas exchange Signup and view all the answers

Which histological stain is described as a mixture of acidic and basic dyes?

Leishman's stain Signup and view all the answers

What characterizes spherocytosis in red blood cells?

Cells appear biconvex with a dark center Signup and view all the answers

What effect does exposure to a hypotonic solution have on red blood cells?

Cells swell and may rupture Signup and view all the answers

What component forms fibrous structures during blood clotting?

Fibrin Signup and view all the answers

What is the main role of hemopoietic stem cells?

To produce various blood cell types Signup and view all the answers

Which of the following choices pertains to the formed elements of blood?

Erythrocytes Signup and view all the answers

What structural feature of RBCs allows them to adapt their shape while traveling through capillaries?

Biconcave shape Signup and view all the answers

What type of stem cell is responsible for the generation of all blood cells?

Pluripotential Hemopoietic stem cell Signup and view all the answers

What is the first precursor (blast cell) in the formation of red blood cells?

Proerythroblast Signup and view all the answers

Which of the following is not a type of progenitor cell?

Pluripotential stem cell Signup and view all the answers

What is the primary function of colony forming unit granulocyte-monocyte (CFU-GM)?

To produce white blood cells such as neutrophils and monocytes Signup and view all the answers

Which of the following cells are categorized as mature cells derived from myeloid stem cells?

Erythrocytes and Monocytes Signup and view all the answers

What role do progenitor cells play in blood cell production?

They are committed to producing specific types of blood cells. Signup and view all the answers

What is the product of CFU erythrocytes (CFU-E)?

Red Blood Cells Signup and view all the answers

In which bones does hematopoiesis primarily occur in adults?

Vertebrae, ribs, sternum, sacrum, pelvic bones, proximal ends of femur Signup and view all the answers

Study Notes

Blood and Lymphatic System Module (BMS201)

Overview provided by Prof. Dr. Shehab Hafez, Head of Histology Department, Mansoura University, for the 2024-2025 academic year.
Key objectives:
- Understand normal shape, number, size, and structure of red blood cells (RBCs).
- Correlate RBC structure with its function.
- Knowledge of hemopoiesis, its sites, and hemopoietic stem cells.
- Outline steps of erythropoiesis.

Blood Composition

Blood is a specialized connective tissue composed of cells suspended in plasma.
Formed elements (blood cells) include:
- Erythrocytes (RBCs)
- Leucocytes (WBCs)
- Thrombocytes (blood platelets)

Blood Smear Preparation

Blood cells examined histologically using smears on microscope slides.
Common stains for visualization:
- Neutral stain: Leishman’s (eosin + methylene blue)
- Romanowsky stains: Giemsa, Wright

Structure and Shape of RBCs

Normal shape: Biconcave discs with a pale center, enhancing gas exchange by increasing surface area by 20-30%.
Abnormal shapes include:
- Spherocytosis: Biconvex shape, darker center.
- Crenation: Notching due to hypertonic solution exposure.
- Swelling and rupture: Due to hypotonic solutions, leading to hemolysis.
- Sickle Cell Anemia: Sickle-shaped or teardrop-shaped RBCs, causing fragility and increased blood viscosity.

Size and Concentration of RBCs

Normal diameter: 6-9 µm (average 7.5 µm).
Macocytic anemia: RBC size > 9 µm; Microcytic anemia: size < 6 µm.
Normal RBC concentration:
- Males: 4.1-6.0 million/µL
- Females: 3.9-5.5 million/µL

RBC Structure

High flexibility due to:
- Membrane: Composed of 40% phospholipids, 10% carbohydrates, 50% protein.
- Cytoskeleton: Made of spectrin, ankyrin, and actin, enabling shape change.
Lack of nucleus and organelles; filled with hemoglobin and enzymes for anaerobic glycolysis.
RBC life span: approximately 120 days, with removal by macrophages in the spleen, liver, and bone marrow.

Hemopoiesis

Definition: Continuous replacement of blood cells through differentiation and maturation of stem cells.
Sites of hemopoiesis vary by age:
- Fetus: Yolk sac (0-2 months), liver and spleen (2-5 months), bone marrow (5-9 months).
- Infants and Adults: Primarily in the bone marrow (vertebrae, ribs, sternum, sacrum, pelvic bones).

Hemopoietic Stem Cells (HSCs)

Pluripotential HSCs maintain their population via self-renewal and proliferate into progenitor cells:
- Myeloid stem cells
- Lymphoid stem cells
Types of progenitor cells include:
- Myeloid: CFU-GM (neutrophils, eosinophils, monocytes, basophils), CFU-E (erythrocytes), CFU-Meg (megakaryocytes/platelets).
- Lymphoid: CFU-L (B-lymphocytes, T-lymphocytes, natural killer cells).

Erythropoiesis

Initiated from the hematopoietic stem cell, progressing through several cell types:
- Proerythroblast → Basophilic erythroblast → Polychromatophilic erythroblast → Orthochromatophilic erythroblast → Reticulocyte → Mature erythrocyte.
Reticulocytes make up 1% of total RBCs, containing a reticulum of ribosomal RNA and mitochondria.
Reticulocytosis occurs after significant RBC loss, increasing production rate in the bone marrow.

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Description

Test your knowledge on red blood cells with this quiz focusing on their structure, function, and production. Understand the implications of sickle cell anemia and learn about the key characteristics and lifespan of red blood cells. Perfect for students studying human biology or related medical fields.