Hematology and Immunology Overview

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Questions and Answers

What type of cells do plasma cells originate from?

Dendritic cells

Activated B-cells (correct)

Macrophages

Activated T-cells

What distinguishes the secondary response carried out by memory cells from the primary response?

Memory cells produce antibodies with greater affinity. (correct)

Memory cells do not use immunoglobulins.

Memory cells have slower response time.

Memory cells produce fewer antibodies.

What is the primary function of opsonization?

To increase inflammation

To block bacterial adhesion

To neutralize toxins

To enhance phagocytosis (correct)

How many heavy chains are found in the structure of an antibody?

Two Signup and view all the answers

What are the two sections located at the ends of the Y's arms of an antibody called?

Variable regions Signup and view all the answers

Which immunoglobulin is the first class produced in a primary response to an antigen?

IgM Signup and view all the answers

What is the primary role of IgG in the immune response?

Activate complement system Signup and view all the answers

Which immunoglobulin binds to mast cells and basophils?

IgE Signup and view all the answers

Which immunoglobulin is most abundant in external secretions like saliva and tears?

IgA Signup and view all the answers

What role does IgA play in relation to infants?

Transfers maternal immunity Signup and view all the answers

What is the primary function of the immune system?

Defending against invading pathogens Signup and view all the answers

Which types of immunity are identified in the immune system?

Innate immunity and acquired immunity Signup and view all the answers

What role do lymphoid organs play in the immune system?

They house lymphocytes and initiate immune responses Signup and view all the answers

What component allows immune cells to move outside the blood and lymphatic system?

Recticulo-endothelial system (RES) Signup and view all the answers

What is the significance of immune surveillance?

It identifies and destroys abnormal or mutant cells Signup and view all the answers

Where are lymphocytes primarily generated?

Bone marrow and thymus Signup and view all the answers

What do the primary lymphoid organs include?

Bone marrow and thymus Signup and view all the answers

What kind of protection does immunity provide the body?

Non-specific and specific protection Signup and view all the answers

Which type of immunity is primarily mediated by T lymphocytes?

Cellular immunity Signup and view all the answers

What is the primary function of the innate immune system?

To provide immediate combat against pathogens Signup and view all the answers

What role do CD4+ T cells play in the immune system?

Help B lymphocytes and cytotoxic T cells Signup and view all the answers

Which component is NOT part of the innate immune system?

Antibodies Signup and view all the answers

Which of the following is NOT a type of B lymphocyte?

Cytotoxic cells Signup and view all the answers

Which action is a primary role of the complement system?

Enhancing phagocytosis of pathogens Signup and view all the answers

Where do T lymphocytes develop and mature?

Thymus Signup and view all the answers

What distinguishes self from non-self in the innate immune system?

Recognition of molecules inherent to the body Signup and view all the answers

What is the main function of plasma cells in the immune response?

Produce antibodies Signup and view all the answers

Which T cells are primarily responsible for directly killing infected cells?

Cytotoxic T cells Signup and view all the answers

Which of the following statements about innate immunity is false?

It reacts in a highly specific manner to pathogens. Signup and view all the answers

What role do C5a and C3a play in the immune response?

Act as chemo-attractants for leukocytes Signup and view all the answers

What percentage of lymphocytes do T lymphocytes constitute?

80% Signup and view all the answers

Which immune response involves cooperation between B cells and T cells?

Humoral immunity Signup and view all the answers

What is an immediate response of the innate immune system?

Recruitment of immune cells Signup and view all the answers

Which feature is characteristic of innate immunity?

It has a restricted set of reactions. Signup and view all the answers

Study Notes

Immunology Overview

Immunology studies the components and function of the immune system, essential for defending against foreign pathogens, microbial toxins, and tumor cells.
The immune system is a complex network of cells, tissues, organs, and soluble factors that provide both non-specific and specific defenses.

Structure of the Immune System

Immune system organs are distributed throughout the body, facilitating the recognition and destruction of foreign substances.
The reticulo-endothelial system (RES) allows immune cells to move outside the blood and lymphatic systems.
Key systems involved include the extracellular fluid system, the blood circulatory system, and the lymphatic system, which houses lymphoid organs.

Lymphoid Organs

Primary lymphoid organs, such as bone marrow and thymus, are sites for lymphocyte development and maturation.
Secondary lymphoid organs (spleen, lymph nodes) initiate adaptive immune responses and facilitate lymphocyte proliferation.

Functions of the Immune System

Defends against invading pathogens, removes damaged tissues, and identifies and destroys abnormal cells, crucial for cancer prevention.

Types of Immunity

Immunity encompasses innate (non-specific) and acquired immunity (specific).
Innate immunity provides immediate defense against pathogens through epithelial barriers, phagocytes, and complement proteins.

Innate Immunity

Acts as the first defense line; components include immediate microbial combat, instructing the adaptive immune system, clearing dead tissue, and initiating repair processes.
It distinguishes self from non-self without generating immunogenic memory.

Complement System

A collection of proteins playing a central role in innate immunity, consisting of three activation pathways.
Functions include opsonization, inflammation (via C3a and C5a), and cell lysis through membrane attack complexes.

Adaptive Immunity

Develops targeted resistance against specific foreign substances such as bacteria and viruses and involves lymphocytes.
Composed of cellular immunity (T cells) and humoral immunity (B cells and antibodies).

Lymphocyte Development

Lymphocytes develop in the bone marrow and are categorized into T and B lymphocytes.
T lymphocytes (80% of lymphocytes) mature in the thymus; key types include CD4+ (helper) and CD8+ (cytotoxic) cells.
B lymphocytes (20% of lymphocytes) are responsible for antibody production and are activated in the bone marrow.

Functions of T Cells

CD8+ T cells are cytotoxic, while CD4+ T cells assist in the activation and proliferation of other immune cells.
Cellular immunity is vital for organ graft rejection, anti-tumor responses, and collaboration with B cells in humoral immunity.

B Cells and Humoral Immunity

B cells, constituting 20% of lymphocytes, produce antibodies (immunoglobulins) through plasma cells derived from activated B cells.
Memory cells enhance response speed and antibody affinity upon re-exposure to antigens.

Antibody Functions

Antibodies are proteins produced by B cells that enhance phagocytosis (opsonization), block pathogen adhesion (neutralization), activate the complement system, and increase inflammation.

Antibody Structure

Composed of two heavy chains and two light chains, forming a Y-shaped molecule with variable and constant regions.
Ig classes include IgD, IgM, IgG, IgE, and IgA, each serving specific functions in immune response.

Immunoglobulin Classes

IgD: Found on B-cell surfaces; function mainly unknown.
IgM: First antibody class produced during a primary response; effective in complement activation.
IgG: Most abundant in serum; provides passive immunity to fetuses and activates complement.
IgE: Mediates immediate hypersensitivity reactions; binds to mast cells and basophils.
IgA: Predominant in external secretions (milk, saliva); provides passive immunity to infants.

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Description

This quiz covers the fundamentals of hematology and immunology, focusing on the immune system's structure and functions. It serves to enhance understanding of how the immune system protects the body against pathogens, toxins, and tumor cells. Test your knowledge on the critical components that contribute to human survival.