SCIE1440: Intro to Immunology & Hematology

Questions and Answers

What is the average blood volume in an adult?

4-6L

What percentage of blood is composed of plasma?

55%

What is the main function of erythrocytes?

Transport oxygen and excrete carbon dioxide

Define hematopoiesis.

The dynamic process of blood cell production and development Signup and view all the answers

Which of the following organs are involved in hematopoiesis?

All of the above Signup and view all the answers

All blood cells are derived from hematopoietic stem cells.

True Signup and view all the answers

What percentage of plasma is made up of proteins?

7% Signup and view all the answers

Match the blood cells to their main functions:

Erythrocytes = Transport oxygen and excrete carbon dioxide Leukocytes = Fight infection Thrombocytes = Hemostasis Lymphocytes = Cellular and humoral immunity Signup and view all the answers

Name the most common skeletal sites for hematologic studies.

Pelvis, vertebrae, ribs, sternum, skull Signup and view all the answers

What is the role of cytokines in hematopoiesis?

Influence the division and differentiation of progenitor cells Signup and view all the answers

The average male has __ L of blood volume.

5-6 Signup and view all the answers

The liver is the primary site of RBC production until the __ month of gestation.

sixth Signup and view all the answers

What is the size range of a basophilic normoblast?

12 to 17 µm Signup and view all the answers

What is the N:C ratio of a basophilic normoblast?

6:1 to 4:1 Signup and view all the answers

Basophilic normoblasts are not usually found in normal bone marrow.

False Signup and view all the answers

How long does it take for basophilic normoblasts to develop?

about 20 hours Signup and view all the answers

Which statement is true about the polychromatophilic normoblast?

It is smaller than basophilic normoblasts. Signup and view all the answers

What is the N:C ratio for an orthochromatic normoblast?

1:1 to 1:2 Signup and view all the answers

Erythrocytes are capable of synthesizing hemoglobin.

False Signup and view all the answers

In what stage does the nucleus of a normoblast become pyknotic?

orthochromatic normoblast Signup and view all the answers

Which of the following is NOT a characteristic of a reticulocyte?

Contains a nucleus Signup and view all the answers

What is the average blood volume in an adult?

4 to 6 L Signup and view all the answers

The process of producing and developing various blood and marrow cells is called _____

hematopoiesis Signup and view all the answers

What are the two types of potential stem cells that all blood cells are derived from?

Multipotential stem cells and pluripotential stem cells Signup and view all the answers

What are colony forming units (CFUs)?

Types of committed cells derived from multipotential stem cells. Signup and view all the answers

What hormone is produced primarily by the kidneys and stimulates erythroid precursors?

Erythropoietin (EPO) Signup and view all the answers

What is the lifespan of erythrocytes?

120 days Signup and view all the answers

Megakaryocytes decrease in size as they mature.

False Signup and view all the answers

What do interleukins (ILs) regulate in hematopoiesis?

They regulate proliferation and differentiation of precursor cells. Signup and view all the answers

List the developmental stages of erythrocytes from immature to mature.

Pronormoblast, basophilic normoblast, polychromatophilic normoblast, orthochromatic normoblast. Signup and view all the answers

Erythropoiesis takes about ______ days to produce erythrocytes.

5 Signup and view all the answers

What are the dietary requirements for RBC maturation?

Protein, iron, Vitamin B12, folic acid, vitamins B6, trace metals. Signup and view all the answers

Match the cell type with its characteristic or function:

Erythrocytes = Oxygen transport Granulocytes = Defense against bacterial infection Lymphocytes = Cellular and humoral immunity Platelets = Coagulation/hemostasis Signup and view all the answers

What defines pyknosis in cell maturation?

Extreme condensation of nucleus. Signup and view all the answers

What is the nuclear-to-cytoplasmic (N:C) ratio in a pronormoblast?

8:1 to 6:1 Signup and view all the answers

What is the primary function of EPO?

Stimulates the production and differentiation of red blood cells. Signup and view all the answers

What is the average lifespan of granulocytes?

9-10 days Signup and view all the answers

What does the term 'basophilia' refer to as cells mature?

Decrease in RNA staining Signup and view all the answers

What is a distinguishing feature of polychromatophilic normoblasts compared to earlier stages?

Cytoplasm appears blue-pink Signup and view all the answers

What happens to the nucleus of an orthochromatic normoblast?

It becomes pyknotic and extruded Signup and view all the answers

What is the N:C ratio of an orthochromatic normoblast?

1:1 to 1:2 Signup and view all the answers

How can the cytoplasm of an orthochromatic normoblast be described?

Predominantly pink with minimal blue Signup and view all the answers

What characteristic distinguishes committed hematopoietic progenitor cells?

They develop into a single distinct cell line. Signup and view all the answers

What is a characteristic of the nuclear chromatin pattern in orthochromatic normoblasts?

Highly clumped with no parachromatin Signup and view all the answers

Where does the process of intramedullary hematopoiesis primarily occur?

Within the bone marrow. Signup and view all the answers

What is the maturation time for an orthochromatic normoblast?

48 hours Signup and view all the answers

What causes the loss of the ability to divide in orthochromatic normoblasts?

Absence of parachromatin Signup and view all the answers

What type of cells are known to directly enter the bloodstream via sinusoids in the bone marrow?

Granulocytes. Signup and view all the answers

Which of the following is true about polychromatophilic and orthochromatic normoblasts?

Polychromatophilic have a lower basophilia than earlier stages Signup and view all the answers

What changes occur to the size of white blood cells as they mature?

They decrease in size. Signup and view all the answers

Which statement correctly describes the distribution of hematopoietic tissue in the bone marrow?

Each cell type occupies unique territories. Signup and view all the answers

What is indicated by the presence of RBC clusters around iron-laden macrophages in bone marrow?

A sign of healthy RBC maturation. Signup and view all the answers

What is the role of the endothelium lining the sinusoids in the bone marrow?

To regulate the passage of developing blood cells. Signup and view all the answers

What unique characteristic is associated with megakaryocytes as cells mature?

They increase in size significantly. Signup and view all the answers

How do developing cell lines in the bone marrow enter the bloodstream?

By crossing the walls of the sinusoids. Signup and view all the answers

What defines the territories occupied by hematopoietic cells in the bone marrow?

They have specific locations that correspond to their functions. Signup and view all the answers

What is the primary distinguishing feature of a reticulocyte compared to a mature erythrocyte?

Presence of ribosomal material Signup and view all the answers

How does the metabolic capacity of a mature erythrocyte differ from that of a reticulocyte?

Mature erythrocytes have limited metabolic activity. Signup and view all the answers

What is the expected percentage of reticulocytes in normal circulating blood?

1-2% Signup and view all the answers

Which staining technique is utilized to visualize reticulocytes in peripheral blood?

New methylene blue stain Signup and view all the answers

What characteristic of erythrocytes allows them to navigate through the microcirculation effectively?

Pliability and deformability Signup and view all the answers

Reticulocytosis is indicative of which condition in the blood?

Increased erythropoietic activity Signup and view all the answers

What is the primary limitation of a mature erythrocyte's metabolism?

Absence of a nucleus Signup and view all the answers

What defining feature does the new methylene blue stain reveal in reticulocytes?

Artifact of network or reticulum within the cytoplasm Signup and view all the answers

At what age does the bone marrow become the only normal site of RBC production?

By 3 weeks of age Signup and view all the answers

When do fat cells begin to appear in long bones during the process of hematopoiesis?

At 4 years Signup and view all the answers

What is the composition of bone marrow by adulthood?

50% fat and 50% cells Signup and view all the answers

Which of the following statements about red and yellow marrow is correct?

Red marrow is active and yellow marrow is inactive. Signup and view all the answers

What primarily happens to the hematopoietic marrow as a child grows into adulthood?

It is replaced by fatty marrow in long bones. Signup and view all the answers

Which skeletal sites retain active hematopoietic marrow in adults?

Pelvis, vertebrae, ribs, sternum, skull, and proximal extremities Signup and view all the answers

What percentage of bone marrow is composed of red marrow at birth?

90% Signup and view all the answers

What change occurs to the structure of marrow as a child approaches adulthood?

The proportion of fat increases as cell demand decreases. Signup and view all the answers

By the age of 18-20 years, in which area is hematopoietic marrow exclusively found?

Sternum, ribs, pelvis, vertebrae, and skull Signup and view all the answers

What role do precursor cells play in hematopoiesis?

They act as the intermediates in the development of mature blood cells. Signup and view all the answers

Which statement describes the progression of active marrow sites from infancy to adulthood?

Hematopoietic activity decreases while yellow marrow increases with age. Signup and view all the answers

What is the primary characteristic of yellow marrow?

It is primarily composed of fat cells. Signup and view all the answers

What indicates that the demand for active marrow has decreased by the age of 4?

Increased fatty infiltration begins. Signup and view all the answers

What type of cells are produced during hematopoiesis?

Progenitor and precursor cells predominantly Signup and view all the answers

What is the percentage range of orthochromatic normoblasts found in normal bone marrow?

5% to 10% Signup and view all the answers

Which of the following statements accurately describes the presence of orthochromatic normoblasts in blood?

They can be present in the blood of newborn infants. Signup and view all the answers

What is the size range for an orthochromatic normoblast?

8 to 12 µm Signup and view all the answers

What happens to the nucleus of an orthochromatic normoblast before it becomes a reticulocyte?

It undergoes condensation and is extruded. Signup and view all the answers

Which of the following correctly describes the characteristics of an orthochromatic normoblast?

It possesses a full complement of hemoglobin and a pyknotic nucleus. Signup and view all the answers

Study Notes

Hematology Overview

"Hema" refers to blood; "ology" denotes the study of.
Hematology focuses on blood, blood-forming organs, blood cells, and coagulation factors.

Blood Volume

Average adult blood volume: 4-6 liters.
Males typically have 5-6 liters; females have 4-5 liters.
Blood composition: ~55% plasma and ~45% cell components (WBCs, RBCs, PLTs).

Plasma Components

Plasma is mostly water (90-92%).
Proteins (~7%): includes albumin, globulin, fibrinogen.
Organic solutes: urea, creatinine, glucose.
Inorganic solutes: Na, K, Ca, Cl.
Contains respiratory gases and enzymes, hormones, antibodies.

Blood Cells

Three main types of blood cells:
- Erythrocytes (RBCs): Transport oxygen and carbon dioxide.
- Leukocytes (WBCs): Fight infections through various subtypes.
- Thrombocytes (Platelets): Involved in hemostasis (blood clotting).

Functions of Blood Cells

Granulocytes:
- Combat infections and trigger immune responses.
- Subtypes: Neutrophils, Eosinophils, Basophils.
Lymphocytes: Vital for cellular and humoral immunity (antibody production).
Monocytes: Phagocytosis and secretion of cytokines.
Erythrocytes: Responsible for respiratory gas exchange.
Platelets: Key in hemostatic functions.

Hematopoiesis

Defined as the dynamic process of blood cell production and development.
All blood cells originate from hematopoietic stem cells.
Continuous turnover of cells is essential for maintaining healthy blood cell populations.

Hematopoietic System

Major components: organs, pluripotent stem cells, regulatory factors (growth factors).
Organs involved include bone marrow, liver, spleen, lymph nodes, and thymus.
The system adapts to needs, increasing specific cell types during infection, bleeding, or hypoxia.

Sites of Hematopoiesis in Pregnancy and Infancy

Mesoblastic Phase (3rd-12th week): Blood islands in the yolk sac produce embryonic hemoglobin.
Hepatic Phase (Beginning fifth week): Liver is the primary site for RBC production until the sixth month.
Myeloid Phase (Around 7th month): Bone marrow becomes the sole site for RBC production post-birth.

Bone Marrow Function and Development

At birth, bone marrow is the primary site for blood cell development.
By 18-20 years, active hematopoietic marrow is found predominantly in the sternum, ribs, pelvis, and skull.
Adulthood: Marrow composition shifts to ~50% fat and ~50% cells, with decreased active marrow as fat infiltration occurs.

Key Objectives for Study

Understand definitions and phases of hematopoiesis.
Identify organs related to hematopoiesis in the fetus.
Recognize cell maturation sequences and the essential functions of different blood cells.
Know common skeletal sites for hematologic studies.### Erythrocytic Development Stages
Basophilic Normoblast (Prorubricyte) Characteristics
- Deep blue cytoplasm with potential pale perinuclear halo.
- Nucleus is reddish-purple, with homogeneous lacy chromatin and 1-3 possible nucleoli.
- Size ranges from 12 to 17 µm; N:C ratio is 6:1 to 4:1.
- Comprises 1% to 5% of normal bone marrow.
- Accumulates more RNA and hemoglobin upon maturation.
Polychromatophilic Normoblast (Rubricyte) Characteristics
- Smaller than basophilic normoblasts, measuring 10 to 15 µm.
- Cytoplasm shows a blue-pink coloration due to mixed RNA and hemoglobin.
- Nuclear chromatin is thickened and irregularly condensed; nucleoli are not visible.
- Maturation lasts about 30 hours, rarely seen in adult peripheral blood.
Orthochromatic Normoblast (Metarubricyte) Characteristics
- Recognized by a solid, pyknotic nucleus with non-linear clumped chromatin.
- Predominantly pink cytoplasm due to hemoglobin synthesis; minimal bluish hue may persist from RNA.
- N:C ratio is 1:1 to 1:2; genotypic size is 8 to 12 µm.
- Maturation time is approximately 48 hours.
- Not found in the blood of adults but may appear in newborns.
Reticulocyte Characteristics
- Non-nucleated cell derived from the orthochromatic normoblast.
- Contains approximately two-thirds of total hemoglobin; bluish staining remains due to RNA presence.
- Typically 1-2% of circulating blood; matures into a fully functional erythrocyte within 1-2 days.
Mature Erythrocyte (Red Blood Cell) Characteristics
- Lacks nucleus, mitochondria, or ribosomes, limiting hemoglobin synthesis.
- Specialized structure facilitates oxygen transport through microvasculature.
- Average lifespan is approximately 120 days.

Hematopoiesis Overview

Hematopoiesis is the production and development of blood cells.
Initiates in the yolk sac, transitions to the liver and spleen, and settles in the bone marrow by the seventh month.
Erythropoiesis involves development from pronormoblast to mature erythrocyte, requires specific nutrients:
- Protein, iron, Vitamin B12, folic acid, B6, and trace metals.

Key Structural Changes During Cell Maturation

Overall cell size decreases as cellular maturity increases; exceptions include megakaryocytes.
Nuclear-to-cytoplasmic (N:C) ratio diminishes as the nucleus shrinks and cytoplasm expands.
Chromatin transitions from a loose arrangement to a more clumped, condensed appearance.
Nucleoli are present in immature cells but disappear in mature forms.

Factors Influencing Erythropoiesis

Erythropoietin (EPO) is a key growth factor produced primarily by the kidneys, crucial for red blood cell development.
Colony Stimulating Factors (CSFs) and Interleukins (ILs) assist in the regulation of blood cell proliferation and differentiation.
Testing EPO levels can indicate conditions such as anemia or kidney dysfunction.

Blood Composition

Blood consists of approximately 55% plasma and 45% formed elements (RBCs, WBCs, platelets).
Normal adult blood volume ranges from 4 to 6 liters.
Plasma comprises mainly water (91.5%), proteins (7%), and other solutes (1.5%).

White Blood Cells Overview

Composition includes segmented neutrophils (50% to 70% of leukocytes), band neutrophils (2% to 6%), eosinophils (0% to 4%), basophils (0% to 2%), lymphocytes (20% to 44%), and monocytes (2% to 9%).
Each cell type has distinct roles in immune response and defense mechanisms.

Myeloid Development and Bone Marrow Function

By three weeks of gestation, the bone marrow becomes the sole site of red blood cell (RBC) production.
In children, all bone marrow is active; in adults, active hematopoietic sites include the pelvis, vertebrae, ribs, sternum, skull, and proximal ends of long bones.
Fatty marrow, which develops as a result of aging, can be reactivated to aid in compensating for anemia.

Hematopoiesis Overview

Hematopoiesis occurs primarily in bone marrow at birth, indicating a critical role in blood cell development.
Active marrow growth shifts from all bones at birth to specific sites, such as sternum, ribs, pelvis, vertebra, and skull, by 18-20 years of age.
By the age of four, fat cells appear in long bones, with adult bone marrow consisting of about 50% fat.

Blood Cell Lineage

Hematopoiesis involves the production of stem cells, progenitor cells, and precursor cells, with committed cells developing into identifiable cell lines.
Cells in hemopoietic cords of the bone marrow move to blood via sinusoids, exhibiting a structured internal organization.

Cellular Characteristics During Maturation

As cells mature, the overall size of white blood cells (WBCs), RBCs, and platelets decreases, except for megakaryocytes.
Polychromatophilic normoblasts are characterized by a low nucleus-to-cytoplasm (N:C) ratio with condensed chromatin and a blue-pink cytoplasm.

Normoblast Development

Orthochromatic normoblasts exhibit a pyknotic nucleus unable to divide, characterized by a predominately pink cytoplasm due to hemoglobin synthesis.
Maturation of orthochromatic normoblasts lasts approximately 48 hours, with their presence in normal bone marrow between 5% and 10%.

Reticulocyte Features

A reticulocyte is formed after the nucleus is extruded from an orthochromatic normoblast, retaining some RNA, giving it a bluish tint.
Normally, reticulocytes constitute 1-2% of circulating blood and mature into RBCs within about one day.

Erythrocyte Functionality

Mature erythrocytes lack a nucleus, mitochondria, or ribosomes and cannot synthesize hemoglobin but maintain limited metabolism for survival in circulation.
Erythrocytes are crucial for transporting oxygen from the lungs to body tissues and can deform to navigate microcirculatory pathways.

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Description

This quiz covers the fundamentals of immunology and hematology, focusing on the study of blood and its components. Key topics include blood volume, blood cells, and coagulation factors. Ideal for students in the SCIE1440 course seeking to reinforce their understanding of these essential biological systems.