The IMMUNE System

Unit 3

Transportation Systems

Functions of the Immune System

• Provide immunity to the body by protecting against disease.
• Identify and kill pathogens and tumor cells.
• Produces white blood cells and antibodies.
• Filters out organisms that cause disease.

Structures of the Immune System

Tonsils

• Lymphoid tissue located on either side of the throat.
• Destroy harmful organisms that enter the body through the mouth.

Lymph Nodes

• Filters or traps foreign particles.
• Contain white blood cells.
• Found throughout the body in the neck, armpit, chest, abdomen, elbows, groin, and knees.

White Blood Cells

• Protect against infection and disease.
• Produced in the bone marrow and move to other parts of the body until they’re needed to fight infection.
• Not released into the bloodstream until they’re needed.

5 MAJOR BARRIERS

• TEARS
• SALIVA
• SKIN
• MUCOUS MEMBRANES
• STOMACH ACID

YOUR BODY DEFENDS ITSELF

If a pathogen gets past one of the five major barriers, your body’s immune system takes over.

immune system A combination of body defenses made up of the cells, tissues, and organs that fight off pathogens and disease

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YOUR BODY DEFENDS ITSELF

Your immune system’s two main responses are the nonspecific response and the specific response.

Together, these responses provide immunity.

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immunity Your body’s ability to resist germs that cause a particular disease

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NONSPECIFIC IMMUNE RESPONSE

The nonspecific response begins with inflammation.

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inflammation The body’s response to injury or disease, resulting in a condition of swelling, pain, heat, and redness

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NONSPECIFIC IMMUNE RESPONSE

With inflammation, the body starts producing a protein called interferon to stimulate the body’s immune system.

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SPECIFIC IMMUNE RESPONSE

Each specific response is customized to attach a particular pathogen and its toxins.

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Our immune system can “recognize” pathogens it has already battled.

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THE LYMPHATIC SYSTEM

The fluid circulation in the lymphatic system is called lymph (LIMF).

lymphatic system A secondary circulatory system that helps the body fight pathogens and maintains its fluid balance

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THE LYMPHATIC SYSTEM

The two types of lymphocytes are B cells and T cells.

lymphocytes The white blood cells in the lymphatic system

B cells form in the bone marrow. T cells develop in the thymus gland.

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THE LYMPHATIC SYSTEM

Macrophages are found in the lymph.

Their purpose is to attach themselves to invading pathogens and destroy them.

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ANTIBODIES AND ANTIGENS

Lymphocytes react to antigens.

antigen Any substance released by invading pathogens

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ANTIBODIES AND ANTIGENS

The immune system responds to antigens by producing antibodies.

antibodies Proteins that attach to antigens, keeping them from harming the body

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ANTIBODIES AND ANTIGENS

• B cells produce a specific antibody for each specific antigen.
• T cells either stimulate the production of B cells or attack pathogens directly.
• The two types of T cells are helper cells and killer cells.

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IMMUNITY

Everyone is born with a natural immunity.

Immunity also develops when a vaccine is used.

vaccine A preparation of dead or weakened pathogens that causes the immune system to provide antibodies

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IMMUNITY

To keep your body healthy, it is important to keep vaccinations current.

Vaccines protect not only you but those around you.

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