Immune System Structures, Components and Functions By Tim Savelle Agriculture Teacher Morgan County High School Veterinary Science The Army Within

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Immune System Protects body from harmful substances Includes: Lymphatic system Respiratory system Gastrointestinal system Integumentary system

Lymphatic System Primary immune system component (Disease Defense System) Functions: To control flow of lymph fluid To produce lymph system components To filter lymph fluid and blood

Lymphatic System Structures 1.Lymph Fluid Interstitial fluid (fluid between cells) Clear, colorless tissue fluid Helps “feed” cells with nutrients Moves hormones around body Removes & transports waste from cells

2. Lymph Vessels (capillaries) Thin-walled tubes separate from blood vessels Contain valves to prevent “backflow” Move lymph fluid into lymph nodes for filtering Lymphatic System Structures

3. Lymph Nodes Filter lymph fluid Remove bacteria and viruses Store white blood cells Lymphatic System Structures

4. Tonsils Masses of lymph tissue Contain lymph nodes and lymph vessels Protect nose and upper throat Lymphatic System Structures

5. Spleen Lymphatic tissue located in the cranial thoracic region Produces white blood cells Filters blood Stores red blood cells Lymphatic System Structures

6. Thymus Lymph gland located medially in the cranioventral area of the thoracic cavity Most active in young animals Place where some white blood cells produced in bone marrow reproduce and mature Lymphatic System Structures

7.Bone Marrow Located in the epiphysis of long bones Produces white blood cells Lymphatic System Structures

1.White Blood Cells (Leukocytes) Lymphocytes Attack specific antigens Formed in lymph structures & bone marrow Monocytes Very large Formed in bone marrow Mature in thymus Lymphatic System Components

2.Macrophages Phagocyte (eats cells) Develop from monocytes Eats invading cells Eats disabled antigens Lymphatic System Components

3.T-Cells A type of lymphocyte Produced in bone marrow Mature in thymus Coordinate immune system defenses Kill antigens directly on contact Lymphatic System Components

4.B-Cells Also called plasma cells A type of lymphocyte Produced in bone marrow Do not kill antigens directly Produce and release antibodies Lymphatic System Components

5.Antibodies Called Immunoglobins (Ig) Produced by B-Cells Composed of proteins Attack and kill specific antigens “Lock and Key” method of attack Lymphatic System Components

Antigens – substances that the body regards as foreign. Bacteria Fungi Viruses Parasites Allergens Toxins The Antigen/Antibody Response E.Coli Bacteria

Antigens: Have unique, consistent surface patterns Patterns cause body to recognize antigens as enemies Contain surface features called antigenic determinants (binding sites) The Antigen/Antibody Response

Antibodies – disease-fighting proteins produced by the body in response to a specific antigen. Have binding sites that match antigenic determinants on antigens Binding sites are chemical, not physical The Antigen/Antibody Response

“The Lock and Key“ The Antigen/Antibody Response Antibody binding sites match antigen surfaces like a key fits into a lock Most antigen binding sites are keyed to a matching antibody in a healthy immune system.

“Search and Destroy” The Antigen/Antibody Response Antigens have many binding sites on their surfaces. Antibody molecules locate antigens and bind to the surfaces, sometimes in chains. Antibodies disable (kill) antigens Antibodies block antigens from attaching to body cells Antibodies “call” macrophages to come and consume disabled antigens

The Antigen/Antibody Response “Shackled” Prisoners

How does it work? The Antigen/Antibody Response Antigens invade body Patrolling macrophages locate, recognize antigens as enemies, and ingest them. Macrophages “read” antigens and encode T-cells with antigen binding site instructions. Macrophages “dispatch” T-cells with antigen codes.

How does it work? The Antigen/Antibody Response T-cells pass antigen binding instructions to B-cells (plasma cells) Plasma cells produce and release antibodies that match antigen binding sites

How does it work? The Antigen/Antibody Response Macrophages find disabled antigens and consume them. Some T-cells “remember” antigens for faster response the next time an attack occurs.

Search & Destroy

The Army Within 1.Primary Response (1 st infection or vaccination) Lymphocytes “decode” antigens Lymphocytes produce antibodies 2.Secondary Response (future infections) T-cells with memory stored in lymph nodes Rapid response time at next infection Immune System Response

The Army Within 1.Good general health 2.Good nutrition 3.Vaccines (specific antigens) 4.Antitoxins (antibodies) 5.Immune system boosters Stimulate lymphocyte production Improve lymphocyte response time How can we help it fight it’s battles?

The Army Within Infantry Soldiers Antibodies Officers T-Cells Outposts Lymph Nodes Headquarters Spleen Roving Patrols Macrophages Intelligence Macrophages Basic Training B-Cells Special Forces B-Cells, T-Cells Supply Lines Lymph Capillaries

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