The Immune System

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The Immune System

• Dr. Timmel

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What is disease?

• Any change, other than an injury, that disrupts
  the normal functions of the body.
• What this really means is that something is
  forcing your body out of equilibrium.
• If an organism is in a disease condition for too
  long a period of time, death will ensue.

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What are pathogens

• Pathogens are disease causing agents.
• Diseases caused by pathogens are generally called
  infectious diseases.
• Examples of pathogens are
• Viruses (the flu, the common cold, warts)
• Bacteria (strep throat, anthrax)
• Protists (malaria, sleeping sickness)
• Worms (tapeworms)
• Fungi (Athletes foot)

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What is the function of the immune system?

• To fight infection through the production of
  cells that inactivate foreign substances or
  cells.
• Some defenses are non-specific and some are
  specific.
• These defenses work together to both prevent and
  fight off disease.

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Non-specific defenses

• First line of defense The bodies most important
  nonspecific defense is the skin.
• This first line of defense also consists of
  mucus, sweat and tears.
• Consists of physical and chemical defenses.
• Any break in the skin is a possible avenue into
  your body for a disease causing agent.

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Second line of defense

• The inflammatory response. A nonspecific
  response to tissue damage caused by injury or
  infection.
• Infected tissue may become swollen and painful.
• A fever is often a component of the inflammatory
  response.

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What are antigens?

• A foreign substance which triggers a response by
  your immune system.
• Viruses, bacteria and other pathogens are
  examples of antigens.
• The antigen is what is making you sick.

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What are antibodies

• Antibodies are proteins that recognize and bind
  to antigens, inactivating them.
• Each antibody is specific to a certain antigen.
• Once a particular antibody is produced by a body,
  memory B-cells become capable of quickly
  producing them should the body encounter the same
  antigen in the future.

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Vaccination

• The injection of a weakened or killed form of a
  pathogen to produce immunity.
• Vaccines give the patient an active immunity
  against a particular disease and have saved
  millions of lives.
• Allergies Is when the body initiates and
  inflammatory response to a subestance which is
  harmless, such as dust. (Also pollen, cat
  dander, shellfish or peanuts).

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Lymphocytes

• As we should recall from the circulatory system,
  there are four different types of white blood
  cells.
• Phagocytes Cells engulf and destroy pathogens.
• Macrophages Very large phagocytes. Assist the
  activation of B and T Cells.
• T-Cells Provide a defense against abnormal
  cells and pathogens inside living cells. T-Cells
  are formed in the Thymus gland. ( 2 types
  Helper and Killer T cells.)
• B-Cells Provide immunity against pathogens and
  antigens in the body fluids. B-Cells are formed
  in the Bones. ( These cells produce the
  antibodies that disable the pathogen

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Autoimmune disease

• When the bodys own immune system attacks its own
  cells.
• The immune system produces antiself antibodies.
• Examples are type one diabetes, MS and AIDS.

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AIDS

• Acquired Immune Deficiency Syndrome.
• A viral disease in which the bodys T-cells are
  destroyed, leaving the body susceptible to
  secondary infections.
• Causes by the HIV (Human immunodeficiency virus).
  It is a retrovirus, meaning it contains RNA and
  not DNA

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What is lymph?

• It is a clear fluid that is lost by the blood to
  the surrounding tissue.
• Travels through the lymphatic system A network
  of vessels, nodes and organs which collects
  fluids and returns them to the circulatory
  system.
• Contains a large number of white blood cells.

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What are lymph nodes?

• Part of the lymphatic system, lymph nodes are
  small bean shaped enlargements that filter the
  lymph and capture bacteria and other
  microorganism that cause disease.
• When the doctor says you have swollen glands,
  they are actually referring to your lymph nodes.
  They get larger when you are fighting an
  infection.

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Other organs of the immune system

• In addition to lymphocytes, lymph and lymph
  nodes, one gland and one other organ play
  important roles.
• Thymus gland. As mentioned earlier, T-Cells
  mature in the thymus gland.
• Spleen helps to cleanse the blood and remove
  damaged cells from the circulatory system. Also
  contains phagocytes.