Immune System

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Immune System

• SC.912.L.14.52 Explain the basic functions of the
  human immune system, including specific and
  nonspecific immune response, vaccines, and
  antibiotics

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Knowledge and Skills

• Identify and/or explain the basic functions of
  the human immune system, including specific and
  nonspecific immune responses
• Describe how the human immune system responds to
  vaccines and/or antibiotics
• Explain the significance of genetic factors,
  environmental factors, and pathogenic agents to
  health from the perspective of both individual
  and public health

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Pathogens and Human Illness

• Germ theory states that microscopic particles
  cause certain diseases
• proposed by Louis Pasteur
• Joseph Lister 1st doc to clean surgical tools
• Robert Koch - postulates support the theory
• Disease-causing agents are called pathogens

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different types of pathogens

• Bacteria
• cause illness by destroying cells
• release toxic chemicals
• Viruses
• force host cells to make more viruses
• Fungi
• take nutrients from host cells
• occur in warm and damp places
• Protozoa
• use host cells to complete their life cycles
• take nutrients from host cell
• Parasites are multicellular organisms
• grow and feed on a host
• possibly kill the host

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How do Pathogens infect?

• Direct contact
• Exchange of body fluids
• Hand shaking
• Indirect contact
• touching an infected surface
• breathing in infected air
• Vectors
• Mosquitoes
• Fleas

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The immune systems consists of organs, cells, and
molecules that fight infections
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First line of defense

• Skin
• Provides a physical barrier
• Secretes oils and sweat
• Mucous membranes
• Lined with cilia
• Circulatory system
• Transports cells

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Cells and proteins fight the bodys infections

• White blood cells (leukocytes)
• Phagocytes engulf and destroy pathogens
• T cells destroy infected cells
• B cells produce antibodies
• Proteins
• Complement proteins weaken pathogen membranes
• Antibodies make pathogens ineffective
• Interferons prevent viruses from reproducing

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Cytotoxic T cell in action
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Immunity

• Passive immunity transferred through DNA or
  mothers milk
• Active immunity produced in response to
  specific pathogen

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Immune Response

• The immune system has many responses to pathogens
  and foreign cells

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nonspecific responses

• The same for every pathogen
• Inflammation - swelling, redness, pain
• Fever body temp increased
• Stimulates production of interferons

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specific responses

• Begin with the detection of antigens
• Antigens are surface proteins on pathogens
• Each pathogen has a different antigen.

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Types of specific responses

• Cellular immunity - T cells to destroy infected
  body cells
• Humoral immunity uses B cells to produce
  antibodies
• Both responses produce memory cells.
• specialized T and B cells
• provide acquired (active) immunity

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The immune system rejects foreign tissues

• Tissue rejection occurs in organ or tissue
  transplants.
• Tissue rejection is the result of an immune
  response.
• immune system detects protein markers on the
  donor tissue
• makes antibodies against the donors tissue

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Immunity and Technology
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methods to control pathogens

• Antiseptics kill pathogens outside of the body
• do not target specific pathogens
• Vinegar, soap
• Antibiotics kill pathogens inside the body
• target one specific bacterium or fungus
• not effective against viruses (not living)

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A Virus is not alive

• Read the comic
• Explain why viruses are not considered living
  things even though they have their own DNA

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Antibiotic Resistance
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Antibiotic resistance

• Overuse of antibiotics can cause them to become
  ineffective
• Some bacteria in a population have genes that
  make them immune to antibiotics
• These bacteria spread the gene, making the
  antibiotics useless

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Antibiotic Resistance

• Read the comic
• Explain how the bacterium population will rise
  again
• What processes will occur
• Be specific!

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Vaccines

• Artificially produce acquired immunity
• Contain the antigen of a weakened pathogen
• Stimulates a specific immune response
• Causes memory cells to be produced
• Allows immune system to respond quickly to
  infection

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Overreaction of the Immune System

• Allergies

• Autoimmune disorders

• caused by allergens
• Allergens are antigens
• cause inflammation

Explain what is happening here
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Autoimmune disorders

• Read the comic
• Explain what is happening