Immune system

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Immune system
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PathogenDisease causing agent

• Any change (not including injury) that disrupts
  the normal
• functions of the body
• Caused by
• Agents-
• bacteria,viruses,fungi
• Materials in the
  environment
• (cigarette smoke
• Inherited- hemophilia

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Germ Theory

• Louis Pasteur/Robert Kouh-1800 said disease
  caused by germswhat about before?
• What rules do we follow for identifying the
  microorganism that causes a specific disease.
• Kochs Postulates
• Pathogen identified in sick organism not healthy
  one
• Pathogen grown in pure culture
• Healthy organism becomes sick when infected with
  pure culture pathogen
• Pathogen extracted and must be same as original
  pathogen

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Agents of Disease

• Our body is great for pathogens
• Suitable temperature,watery,lots of nutrients
• We already have loads of yeast and bacteria in/on
  us- large intestine, mouth which are either
  harmless or helpful
• What do the pathogens do?
• destroy cells,release toxins, block blood flow,
  remove nutrients,disrupt bodily functions

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• Viruses
• Invade and replicate on the cells using the cells
  own RNA or DNA (thats why we cant kill a
  virusis)
• Bacteria-Most are harmless
• Harmful cause disease in two ways
• 1.breaking down tissue of the 2.infected
  organism or releasing toxins
• Protists ex Malaria, Sleeping sickness
• feed off the nutrients of infected host
• Worms- same as protists
• Fungi- Most harmless- ringworm etc can be deadly

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How are Diseases spread?

• Physical contact
• To help cover your mouth, wash your hands
• Contaminated Food and Water
• All food contains bacteria
• Infected Animals
• The animals that carry the pathogen from person
  to person are called vectors

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How do we fight them?

• Antibiotics- kills the bacteria not the cells
• Over the counter drugs (careful) these treat the
  symptoms not eh disease.

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40.2 Immune system

• Immune systems function is to fight infection
  through the production of cells that inactivate
  foreign substances or cells. This is immunity.
• 1st line of defense is your skin, mucus, sweat,
  tears contain lycoenzyme and salt. Oil and sweat
  glands produce acidic environment.
• Mouth nose and anus are protected by mucus, cilia
  that line your nose and throat help push
  pathogens away from your lungs (Lugie) stomach
  has acid.

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Second line of defense

• Inflammatory response
• Mast cells release histamines that cause the
  blood walls to be leaky. White blood cells then
  cross over into the tissue. Many are phagocytes
  that engulf and destroy bacteria. Tissue swells
  you say ouch!
• Immune can release chemicals that increases (yep,
  you make the temp) Fever . High temp stops or
  slows the growth of many pathogens (Bacteria can
  replicate every 20 minutes)
• For viruses we make proteins called interferon

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Specific Defenses immune response

• Antigen substance that triggers a response Two
  types
• Humoral immunity made of B cells (lymphocytes)
  they provide immunity against antigens and
  pathogens in body fluids)
• Pathogen enters the body and its antigens are
  recognized by B cells which grow and divide
  rapidly, producing large numbers of plasma and
  memory B cells. (memory B cells stay behind after
  pathogen is gone so you will not be reinfected

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Cell mediated Immunity

• T cells defend against abnormal cells and
  pathogens inside living cells. (both are
  lymphocytes)
• They do this by T cells dividing into Killer T
  cells, helper T cells, suppressor Y cells and
  memory B cells.
• T cells kill invader
• Helper T produce memory T cause secondary
  response if pathogen ever comes back
• When attack is under control suppressor T cells
  shut down Killer T
• Problems Transplants

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• Acquired immunity is when we deliberately infect
  a person either by exposure or a Vaccination
• Passive immunity- limited time ex- Moms milk,
  rabies shot, Malaria medication etc

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