Immunology - Lecture 2

Immunology - Lecture 2

• Types of Immune System: The immune system comprises various organs and cells that work together to maintain health.
• Immune System Components: The key components include adenoids, mucosa, white blood cells (WBCs), antibodies, cytokines, complement system, lymph nodes, spleen, tonsils, adenoids, thymus, bone marrow, and skin.
• White Blood Cells (WBCs): WBCs, also known as leukocytes, are responsible for defending the body against infections.
• WBC Function: WBCs circulate in the bloodstream and tissues, identifying and responding to infection sites by notifying other WBCs. They destroy pathogens by producing antibody proteins.
• WBC Characteristics: WBCs are generally colorless but can appear light purple to pink when stained. They are small and have a round shape with a central nucleus. They make up about 1% of blood volume, versus red blood cells.
• WBC Formation: WBCs originate from stem cells within bone marrow. Two types, lymphocytes (B cells and T cells), develop in different locations: B cells mature in bone marrow, T cells mature in the thymus.

White Blood Cell (WBC) Types

• Neutrophils: Protect against infections by killing bacteria, fungi, and foreign debris.
• Lymphocytes: Consist of T cells (helper, regulatory, cytotoxic, memory), natural killer cells, and B cells. B cells produce antibodies. Lymphocytes are crucial for determining the specificity of immune responses.
• Eosinophils: Identify and destroy parasites, cancer cells, and are involved in allergic responses.
• Basophils: Initiate allergic responses through coughing, sneezing, or a runny nose.
• Monocytes: Defend against infection by cleaning up damaged cells.

WBC Normal Count

• Normal WBC count ranges between 4,000 and 11,000 cells per microliter of blood.
• The body produces nearly 100 billion WBCs daily.

Antigens & Antibodies

• Antigens: Substances or toxins present in the blood that trigger an immune response. Antigens are usually from bacteria or viruses, but can be any foreign substance.
• Antibodies: Proteins that protect the body from invaders by binding to them and initiating their destruction.

Heteroantigens & Autoantigens

• Heteroantigens: Substances foreign to the body, such as viruses, bacteria, protozoa, blood cells from other people, allergens, and proteins in foods.
• Autoantigens: Substances made by the body to fight the body's own cells; commonly associated with autoimmune diseases.

Lymphocytes

• Lymphocytes: A white blood cell type with vital roles in immunity. They include B cells and T cells, which originate from stem cells in the bone marrow, with some T cells maturing in the thymus. In humans, most lymphocytes are short-lived, lasting from a week to a few months, but some offer long-lasting immunity.
• Lymphocyte Function: Helper T cells stimulate B cells to produce antibodies, while regulatory T cells control immune reactions. Cytotoxic T cells destroy infected cells.
• Lymphocyte Types (Adaptive): There are B cells and T cells, NK cells, and innate-like lymphocytes.

Lymphocyte Defection Diseases

• Further investigation and knowledge beyond these notes are required to provide detailed disease information.

Explore the key concepts of the immune system in this quiz based on Lecture 2 of Immunology. Learn about various immune system components, the functions and characteristics of white blood cells, and their role in defending the body against infections. Test your knowledge and enhance your understanding of immunological principles.