Hematopoiesis and Blood Cells Quiz

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Questions and Answers

What is the primary function of hematopoietic stem cells?

Differentiate into specific blood cell lineages

Act as support cells for connective tissues

Differentiate into all blood cell types (correct)

Supply the extracellular matrix proteins

Which of the following components is NOT considered a part of the bone marrow hematopoietic microenvironment?

Connective tissue cells

Soluble factors

Adhesion molecules (correct)

Cytokines

What role do soluble factors play in the bone marrow?

They enhance the proliferation of stem cells only.

They form the extracellular matrix.

They primarily provide structural support to cells.

They impact cell function and movement. (correct)

How do hematopoietic cells primarily locate themselves within specific niches of the bone marrow?

Through interaction with adhesion molecules and receptors Signup and view all the answers

What histological characteristic distinguishes progenitor cells from hematopoietic stem cells?

Progenitor cells are larger and have a lower nucleocytoplasmic ratio. Signup and view all the answers

Which type of white blood cell is involved in producing antibodies?

B lymphocytes Signup and view all the answers

What is the primary function of monocytes in the immune system?

Serve as antigen-presenting cells Signup and view all the answers

What characteristic is true about basophils?

They are involved in allergies. Signup and view all the answers

Which cell type is classified as agranulocytes?

Monocytes Signup and view all the answers

What is the primary size range of lymphocytes?

6-15 μm Signup and view all the answers

Which statement about platelets (thrombocytes) is correct?

They play a role in blood coagulation. Signup and view all the answers

What describes the appearance of monocytes?

They exhibit a C-shaped or indented nucleus. Signup and view all the answers

Which type of lymphocyte is primarily responsible for cell-mediated immunity?

T lymphocytes Signup and view all the answers

What is the primary consequence of polycythemia?

Increased blood viscosity Signup and view all the answers

Which of the following is a common cause of anemia-related clinical symptoms?

Stomach ulcers Signup and view all the answers

How does hereditary spherocytosis affect erythrocytes?

It results in fragile, abnormally shaped erythrocytes Signup and view all the answers

What role do integral membrane proteins play in erythrocytes?

They stabilize the cell membrane structure Signup and view all the answers

Which protein is essential for maintaining erythrocyte shape and flexibility?

Spectrin Signup and view all the answers

What could severe polycythemia potentially lead to in terms of circulation?

Potential complications from slower blood flow Signup and view all the answers

Why are erythrocytes prone to hemolysis in certain conditions?

Resulting from abnormal cell shape Signup and view all the answers

What is a key characteristic of erythrocyte membrane composition?

50% proteins and 10% carbohydrates Signup and view all the answers

Which type of white blood cell is primarily involved in the phagocytosis of bacteria?

Neutrophil Signup and view all the answers

What characteristic distinguishes eosinophils from other granulocytes?

Bilobed nucleus Signup and view all the answers

Which type of lymphocyte is primarily responsible for antibody production?

B cells Signup and view all the answers

Which blood cell type has a size range of 7-8 micrometers and functions in oxygen transport?

Erythrocytes Signup and view all the answers

What is the primary function of basophils?

Release histamine during allergic responses Signup and view all the answers

What type of stem cells give rise to all blood cells?

Haematopoietic stem cells Signup and view all the answers

Which cell type is known for forming platelet plugs at injury sites?

Platelet Signup and view all the answers

Which type of white blood cell has a nucleus that is kidney-shaped or horse-shoe shaped?

Monocyte Signup and view all the answers

What is the primary function of transferrin in the blood?

To transport iron through the blood Signup and view all the answers

Which type of lipoprotein is primarily responsible for transporting cholesterol and can appear round or disk-shaped?

Low-Density Lipoproteins (LDL) Signup and view all the answers

What is the main difference between plasma and serum?

Plasma contains coagulation factors, while serum does not Signup and view all the answers

Which anticoagulant is commonly used to prevent blood coagulation in test tubes?

Sodium Citrate Signup and view all the answers

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

To transport oxygen from the lungs to tissues Signup and view all the answers

Which function of blood does NOT involve transport?

Regulation of blood pH Signup and view all the answers

Which component of blood is primarily responsible for hemostasis?

Platelets Signup and view all the answers

How does blood help maintain homeostasis in the body?

By maintaining a stable internal pH and temperature Signup and view all the answers

What type of staining method is used to differentiate between different types of blood cells?

Giemsa and Wright's stains Signup and view all the answers

Which of the following substances is NOT carried by blood during its transport functions?

Light Signup and view all the answers

During what process does serum form from blood?

Clotting process Signup and view all the answers

Which type of white blood cell helps to protect the body by phagocytosing bacteria and viruses?

Granulocytes Signup and view all the answers

What is the average lifespan of red blood cells in circulation?

120 days Signup and view all the answers

What structure in red blood cells allows them to carry more oxygen?

Their biconcave shape Signup and view all the answers

Which of the following best describes the role of hemoglobin in red blood cells?

It carries oxygen from the lungs to tissues Signup and view all the answers

Anemia is defined as having what condition related to red blood cells?

Lower-than-normal red blood cell concentration Signup and view all the answers

Study Notes

Histology of Blood and Bone Marrow

Blood is a connective tissue composed of blood cells and plasma.
When blood is collected in an anticoagulant tube and centrifuged, formed elements (cells) and plasma separate.
Plasma makes up 55% of total blood volume, a pale yellow, transparent, viscous fluid
The formed elements include erythrocytes (red blood cells), that comprise 45% of total blood volume; leukocytes and platelets (the "buffy coat") which comprise less than 1% of total blood volume.
The hematocrit is the sediment formed by erythrocytes (red blood cells RBCs) and represents about 45% of total blood volume.
Plasma is composed of water (90-92%), proteins (albumin, globulins, and fibrinogen), lipids, glucose, amino acids, electrolytes, and waste products.
Plasma proteins include albumin, globulins (α and β, and γ/immunoglobulins), and fibrinogen.
Albumin is the most abundant protein, maintaining colloid osmotic pressure.
Globulins (α and β) have roles in transport and immunity.
Immunoglobulins/Antibodies (γ globulins) are important for immune defense
Fibrinogen crucial for blood clotting.
The plasma also contains important components, such as lipids (chylomicrons, HDL, LDL and VLDL; transferrin important for iron transport in the blood).
Blood volume in an adult is typically between 5 to 6 liters.
Serum is essentially plasma, without coagulation factors (such as fibrinogen).
Blood is commonly mixed with anticoagulants (like sodium citrate, sodium oxalate, and heparin) to prevent clotting.
The liquid part of the blood that stays on top after centrifuging is plasma.
Serum contains growth factors and other proteins released by platelets during clot formation, including thrombin.

Blood Cells

The cellular components of blood include: erythrocytes (4), granulocytes (basophils(1), eosinophils(7), neutrophils(8)), agranulocytes (monocytes(3.5), lymphocytes(6,9)), and platelets (thrombocytes) (2)

Blood's Cellular Elements - Erythrocytes (Red Blood Cells - RBCs)

Erythrocytes are biconcave shaped.
They lack a nucleus.
They contain hemoglobin, to carry oxygen from the lungs to tissues
The function of erythrocytes is gas exchange, without exiting the circulatory system

Blood Smear

A blood smear is prepared to examine blood cells under a microscope.
Staining with Giemsa and Wright's stains helps identify different types of blood cells.

Red Blood Cells (Erythrocytes)

The biconcave shape of RBCs maximizes surface area for efficient oxygen transport.
RBCs have a high number, approximately 4-5 million.
RBCs circulate for about 120 days before being removed and recycled by the spleen and liver.

Clinical Correlations - Anemia

Defined as having lower-than-normal red blood cell concentration
Causes include: iron deficiency, excessive menstrual bleeding, stomach ulcers
Symptoms include: fatigue, shortness of breath, weakness, paleness of the skin, heart palpitations.

Clinical Correlations - Polycythemia (Erythrocytosis)

Elevated red blood cell concentration
Occurs in high altitudes due to physiological adaptation
Increased hematocrit and blood viscosity, affecting blood flow, especially in capillaries

Erythrocyte Membrane Proteins

Membrane proteins maintain erythrocyte shape, elasticity, and strength.
Any disruption in cytoskeletal protein gene expression can cause abnormally shaped and fragile erythrocytes, leading to hemolysis

Erythrocyte Membrane Composition

The Erythrocyte membrane contains proteins (including ion channels, protein bands like band 3,4.1, and 4.2, and glycophorin C) and lipids.
Membrane proteins serve as anion transporters, and some have antigenic sites, relevant for the ABO blood group system.
Peripheral membrane proteins like spectrin and ankyrin maintain erythrocyte shape and flexibility.

Clinical Correlations - Hereditary Spherocytosis

A hereditary condition caused by abnormal cell skeleton formation due to a mutation on the gene that synthesizes band 4.1 protein.
Abnormally shaped red blood cells (spherocytes) are destroyed prematurely in the spleen.
This condition leads to splenomegaly (enlarged spleen) and anemia since the spherocytes are destroyed
Inefficient oxygen transportation due to the altered shape

Clinical Correlations - Hereditary Elliptocytosis

Hereditary condition causing an abnormal cell skeleton formation, thus, changing the shape of blood cells (from biconcave to elliptical)
Defects in band 4.1 protein, as well as, in spectrin and ankyrin, and the glycophorin protein, can result in this condition
Splenomegaly (enlarged spleen) and anemia since the elliptic cells are broken prematurely.

Clinical Correlations - Sickle Cell Anemia

A hereditary condition resulting from a point mutation in the beta-chain hemoglobin gene.
The mutated hemoglobin (HbS) results in sickle-shaped red blood cells which decreases flexibility and increases fragility.
Sickle-shaped cells polymerize and form rigid clusters in capillaries.
Reduced blood flow to tissues leads to complications.

Clinical Correlations - Thalassemia

Genetic defect in hemoglobin synthesis (alpha or beta chains).
Altered hemoglobin structure results in altered red blood cell shape (from biconcave to elliptical)

Leukocytes (WBCs)

Leukocytes leave the bloodstream and migrate to tissues to defend against infections and foreign invaders.
Classified based on cytoplasmic granules (granulocytes or agranulocytes).
- Granulocytes contain specific granules in the cytoplasm (primary and secondary) and are further categorized into neutrophils, eosinophils, and basophils
- Agranulocytes lack visible cytoplasmic granules and are lymphocytes and monocytes.

Granulocytes

Granulocytes have a lobed nucleus and various specific granules in their cytoplasm (different types of granules (azurophilic, specific) contain enzymes and proteins.).
Neutrophils are the most numerous WBCs, involved in phagocytosis.
Eosinophils respond to parasitic infections and allergic reactions, and release chemicals to control inflammation.
Basophils play a role in allergy-related inflammation, releasing chemicals like histamine to regulate inflammation.

Agranulocytes

Agranulocytes have a non-lobed nucleus. The major agranulocytes are lymphocytes and monocytes.
Lymphocytes are classified into B and T lymphocytes. B lymphocytes are responsible for antibody production (humoral immunity), while T lymphocytes are involved in cell-mediated immunity by directly attacking infected cells. Also included are Natural Killer cells (NK cells) which target virus-infected cells and tumors.
Monocytes are phagocytic cells that differentiate into macrophages, critical in the immune system

Platelets (Thrombocytes)

Platelets are derived from megakaryocytes in the bone marrow.
Their function is in blood clotting and serving as filler material during blood coagulation.
Different granules, like alpha and delta granules, contain specific proteins important in the process.

Bone Marrow: Structure and Function

Bone marrow fills the cavities left by the trabecular bone network.
Unlike bone, it is jelly-like and accounts for approximately 4-5% of total body weight
It is responsible for blood cell production.
It also stores fat in the form of adipocytes (particularly in yellow marrow)

Two Types of Bone Marrow

Both types contain specialized cells
Red marrow is involved in hematopoiesis (producing blood cells). found in flat bones and in the proximal ends of long bones
Yellow marrow is primarily composed of adipocytes (fat cells) and found in the medullary cavity of long bones in adults.

Bone Marrow Hematopoietic Microenvironment

Hematopoietic cells (blood-forming cells) interact with support cells, the extracellular matrix (ECM) proteins and soluble factors like cytokines and hormones.
Cells interact with each other and the ECM, affecting their behavior.
Soluble factors like cytokines and hormones influence cell function and movement.
Cells move to specific areas in the bone marrow (niches).
These interactions are important for bone marrow diseases and injuries

Bone Marrow Cells

Hematopoietic stem cells are the initial cells, being multipotent, differentiating into all blood cell types
Progenitor cells develop from hematopoietic stem cells into blood cell lineages (erythroid myeloid, etc.)
Erythroblasts, Myeloblasts and Megakaryocytes are precursors to specialized cells
Macrophages have the function of phagocytosis and participating in the immune response

Clinical Significance of Bone Marrow Cellularity

Hypercellularity means an increase in haematopoietic cells in the bone marrow
Hypocellularity means a decrease in haematopoietic cells in the bone marrow.

Clinical Significance: Bone Marrow Aspiration and Biopsy

Bone marrow aspiration and biopsy are crucial diagnostic procedures for bone marrow problems and assessment
Bone marrow cellular assessment is done thru Aspiration, to look at individual cells
Further assessment is done thru Biopsy to study tissue samples for architectural details (and focal lesions).

Indications for Bone Marrow Aspiration and Biopsy

Evaluating blood cell line depletion (leukopenia, thrombocytopenia, anaemia), to find the cause of cellular depletion.
Investigating abnormal cellular increase (leukocytosis, polycythemia, thrombocytosis), to find the cause.
Assessing Morphological discrepancies and Monitoring disease progression, and therapy effectiveness
Detecting metastatic neoplasms
Investigating Fever of Unknown Origin (FUO) and Lymphadenopathy

Bone Marrow Suppression

Bone marrow suppression, often caused by chemotherapy, results in pancytopenia (reduced production of all blood cell types)
Common drugs causing suppression include methotrexate, azathioprine, and cyclophosphamide

Bone Marrow Failure

A severe condition where the bone marrow can't produce blood cells.
Causes can include damage to hematopoietic stem cells, nutrient deficiencies, or dysfunctional differentiation of blood cells.
Conditions include congenital (e.g., Fanconi's anaemia) or acquired (e.g., aplastic anaemia or chemotherapy).

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Description

Test your knowledge on hematopoietic stem cells, their functions, and the various components of the bone marrow microenvironment. This quiz covers the characteristics and roles of different blood cells, including white blood cells and their immune functions.