The Immune System Lesson 1: The Immune Systems

Lesson Objectives Upon completion of this lesson, students should be able to … Identify and discuss the anatomy of the immune system. Discuss the functions of the immune system. Explain the immune system and its response.

Composition of the Immune System Tissues Organs Physiological processes that identify abnormal cells Foreign substances Foreign tissues, such as transplants

Structures Central to the Immune System Central lymphoid tissue bone marrow, thymus Peripheral lymphoid tissue lymph nodes, spleen, and mucus membranes

Critical Thinking Questions What is so critical about the immune system to one’s overall health? If one has a compromised immune system would that shorten the person’s life?

The Immune System throughout the body part of the lymphatic system subsystem of the CV system Primary fx is to defend against invasion Pathogens (viruses, bacteria, and fungi) Immunosuppressants, medications, and stress can suppress system

The Lymphatic System

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Bone Marrow Contains stem cells that create all the cells Produces RBC’s WBC’s Platelets B cells Natural killer cells

Thymus Gland Located posterior to the sternum Manufactures infection-fighting T cells Helps distinguish normal T cells from those that attack the body Enlarges during childhood Shrinks as we age

Peripheral Lymphatic System Consists of the lymph nodes, spleen, and other lymphoid tissue

Lymph Nodes Different sizes and shapes Most are bean-shaped, about 1 inch long Covered with a thick fibrous capsule

Two Parts of Lymph Nodes Cortex Populated mainly with lymphocytes Medulla Primarily made up of macrophages

B Lymphocytes Responsible for circulating antibodies When an antigen enters the body, B lymphocytes rapidly undergo mitosis and divide This produces a large quantity of an antibody

Spleen Located in the ULQ of the abdomen Lots of blood vessels Spleen’s blood vessels are lined with macrophages swallow and digest debris in the blood worn-out red blood cells and platelets 15

Tonsils used to be removed when infected. Located in the depressions of the throat and the pharynx Fx -filter bacteria aid in the formation of white blood cells Factoid: Tonsils used to be removed when infected. 16

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The Immune System Defense against infectious organisms and pathogenic invaders Immune response cells, tissues, and organs work together to attack pathogen white blood cells (WBCs), seek out and destroy harmful organisms

Phagocytes Phagocytes WBC that attacks the invading organism most common are neutrophils, which fight off bacteria

Lymphocytes Lymphocytes WBC allows the body to remember previous invading organisms Originate in the bone marrow If stays there, it matures into B cells If moves to the thymus gland, they mature into T cells

B and T Lymphocytes B lymphocytes Seek out invading organisms and send defenses to attach onto them T cells Destroy the organisms that the B lymphocytes have id

Antigen Foreign substance that invades the body When an antigen is detected, several types of cells work together to recognize and respond to it These cells trigger the B lymphocytes to produce antibodies This process is known as humoral immunity

Antibodies Specialized proteins that lock onto specific antigens Immunoglobulins Antibodies are found in blood, tissue fluids, and many secretions

B Cells of the Immune System Once antibodies have been produced, they remain in the body If re-infected, the antibodies are already there to neutralize it antibodies can recognize an antigen and lock onto it, but are not capable of destroying it. That is the job of the T cells.

T Cells destroys antigens which have been tagged by antibodies

Immunity The body’s ability to defend itself against pathogens 3 Forms 26

Innate Immunity Born with innate, or natural, immunity Renders many of the viruses and bacteria incapable of harming infant Provided by : Skin Mucous membranes Mother

Active Immunity by infection or with a vaccine Is permanent ??

Types of Active Immunity Acquired active immunity exposed to a live pathogen develops the disease and becomes immune (primary immune response) Artificially acquired active immunity induced by a vaccine (antigen) stimulates a primary response against the antigen without causing symptoms of the disease

Passive Immunity “Borrowed” from another source and lasts for only a short time An inherited immunity to certain diseases

Medical Specialists Allergist Immunologist Oncologist