The Immune System How the body defends itself

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The Immune System - How the body defends itself
Objectives

• List the main types of external defences in
  the body
• Describe the main differences between innate
  and adaptive immunity
• List the main molecules involved in defence
  and where they are found in the body
• List known diseases resulting from a faulty
  or over-active immune system

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Why do you need to know about immunology and the
immune system to be a doctor?

• Infectious diseases lead to illness and
  sometimes death
• The immune system itself can contribute to
  development of disease either by an
  insufficient response or overactive response
• Transplants are becoming more common and we
  need to develop ways of manipulating the immune
  system to prevent graft rejection

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The Immune System
Like any other body system Digestive
system Reproductive system Nervous
system Circulatory system Respiratory
system Excretory system
Function To defend the body
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Range of organisms that invade man
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External Defences of the Body
IgA
IgA
IgA
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Secretions at epithelial surfaces Site Source
Substance secreted Eyes lacrimal glands
(tears) lysosyme, IgA, IgG Ears sabaceous
glands waxy secretion-cerumen Mouth salivary
glands digestive enzymes, lysosyme, IgA,
IgG, lactoferrin Skin sweat glands
(sweat) lysosyme, high NaCL, short chain
fatty acids sebaceous glands (sebum) Stomach Gas
tric juices digestive enzymes, low pH,
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Cells of the Innate immune system
PMN
Monocyte/ macrophage
NK cell
Mast cell
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Mast Cell Granules
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Natural Killer cell killing a virus- infected cell
NK cell
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Molecules of the Innate immune system
Lysosyme
Acute phase proteins
Complement
Cytokines
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Adaptive Immunity Two kinds of lymphocytes T
and B
T lymphocytes T helper cells Tcytotoxic
cells
B lymphocytes
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B lymphocytes make antibodies
With T helper cells
Plasma cells in tissues
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Origin of blood cells - Haemopoiesis
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Diseases where the immune system over-reacts
Disease Antigens Infectious diseases Mycobact
erium eg. TB,leprosy Allergies eg. Hay fever
pollens farmers lung fungi Autoimmune
diseases self-antigens eg. Systemic lupus
erythematosus DNA rheumatoid arthritis IgG
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Leprosy - granulomas caused by an overzealous
immune response
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Allergic to a bee-sting
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The Dust Mite - allergies to the faecal pellets
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Myasthenia gravis - autoimmune disease (anti
acetylcholine receptors)
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Rheumatoid arthritis - autoimmune disease
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Hypersensitivity - Rhesus disease
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Failure of the immune system

• Diseases where the cells do not develop and
  where there are defects in production of the
  molecules. eg. Phagocytes and antibodies
• Suppression of the immune system caused by
  drugs used for
• a) treating cancer
• b) preventing graft rejection
• and infectious agents eg. HIV

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The Immune System - How the body defends itself
Objectives

• List the main types of external defences in
  the body
• Describe the main differences between innate
  and adaptive immunity
• List the main molecules involved in defence
  and where they are found in the body
• List known diseases resulting from a faulty
  or over-active immune system