Immune System Overview Quiz

Study Notes

Immune System Overview

The immune system is a complex network of cells, tissues, and organs that combats disease and infection.
It maintains a record of defeated microbes, enabling swift destruction if re-encountered.
Key organs and tissues include tonsils, adenoids, lymph nodes, lymphatic vessels, thymus, spleen, appendix, bone marrow, and Peyer's patches.

Immune System Function

Protects the body from diseases and foreign substances through white blood cells.
Phagocytes destroy foreign cells, while lymphocytes provide learned immunity.
The lymphatic system is crucial for fluid removal, fat absorption, and immune cell production.
Removes excess fluids, proteins, and substances that leak from capillaries into tissues.
Absorbs fatty acids and transports fat to the circulatory system.
Produces immune cells (lymphocytes, monocytes, plasma cells).

Immune System Components

Bone marrow produces white blood cells.
Lymphoid tissues include the thymus, spleen, lymph nodes, tonsils, adenoids, and related tissues in the gastrointestinal, respiratory, and reproductive systems.

Lymphatic System Anatomy

Lymphatic vessels, similar to veins, have valves that allow one-way flow and produce a beaded appearance.
Lymphatic capillaries (terminal lymphatics) receive interstitial fluid, becoming lymph.
Lymph travels through lymph nodes filtering out debris/pathogens.
The body has about 500-600 lymph nodes, commonly found in groin, armpits, neck, chest, and abdomen.

Lymphocytes

Key cells in adaptive immune responses.
Different types include:
- B lymphocytes: Generate antibodies.
- T lymphocytes: Secrete chemical messengers.
- Plasma cells: Secrete antibodies.
- Natural killer (NK) cells: Destroy virally infected cells.

Lymphoid Organs

Primary lymphoid organs (lymphocyte development):
- Bone marrow: Oversees most hematopoietic functions.
- Thymus: A bilobed organ positioned between the sternum and heart's aorta.
Secondary lymphoid organs:
- Lymph nodes: Filter lymph, removing debris and pathogens.
- Spleen: Filters blood, removing microbes, and damaged red blood cells.
- Tonsils: Located in the pharynx, help with immunity to oral pathogens.

Types of Immunity

Innate/Genetic Immunity:
- Present at birth, a nonspecific, initial defence.
- Includes physical barriers (skin, mucous membranes, inflammation, phagocytosis), and chemical barriers (pH levels, enzymes, interferons, complement system, and natural killer lymphocytes).
Acquired Immunity:
- Develops throughout life, a specific response to pathogens.
- Characterized by specificity, diversity, memory, and self/nonself recognition.
- Two types of acquired immunity are humoral and cell-mediated immunity.

Description

Test your knowledge on the immune system's structure and function. This quiz covers the roles of various organs and cells in protecting the body from diseases. Understand how the immune system maintains memory against pathogens and its interaction with the lymphatic system.