The Immune System Basics

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The Immune System Basics
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Pathogens of Disease

• Bacteria
• Bacteria are cellular (prokaryotic) and are
• Living organisms
• - 3 common shapes
• Bacilli (rod), cocci (circular), spirilli
  (spiral)
• Cause disease by
• Destroying cells and tissue
• Releasing toxins in body
• Examples
• Strep Throat, tetanus, anthrax, syphilis,
  tuberculosis, MRSA, food poisoning, chlamidia,
  gonorhhea
• Preventions
• Some have vaccines, personal hygiene, antiseptics
• Treatments
• Antibiotics- substances that can be administered
  that kill the bacterial cells causing infection
• Usually break down cell walls or interfere with
  metabolic processes

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Pathogens of Disease

• Viruses
• Noncellular particles
• Genetic material (DNA or RNA)
• Capsid-protective coating made of protein
• Not considered living
• Cannot reproduce on own, no metabolic processes,
  no response to stimulus
• Cause disease by
• Disrupting cellular activity and destroying cells
• Examples
• Common Cold, Flu, Small Pox, HIV, chicken pox,
  genital warts, herpes, hepatitis
• Prevention
• Some have vaccines, personal hygiene, antiseptics
• Treatments
• None- body must defeat on own, some the body
  cannot defeat EVER
• Some drugs (antiviral) can slow the spread of
  virus within the body

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Function of the Immune System

• to fight infections and protect the body from
  invaders.
• White Blood Cells-Specialized cells of the immune
  system
• fight disease

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Pathogens

• Bacteria (food poisoning, tuberculosis,
  pneumonia)
• Viruses (influenza, AIDS, colds,ect..)
• Protists (malaria and others)
• Infect body and cause disease!
• Antigen- a substance on the surface of a pathogen
  that triggers an immune response (DEFENSE).

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Nonspecific Defenses

• Skin- Creates barrier between external
  environment where pathogens exist and the inside
  of the body
• Pathogens must enter body to cause
  infection/sickness
• Inflammatory Response (Swelling)-Blood vessels
  expand and WHITE BLOOD CELLS (disease fighters)
  enter the wound or infection site
• Fever- Body raises core temp. to try to kill
  pathogen
• Some pathogens can only survive under certain
  temp.

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Specific Defenses

• Humoral Response
• Involve Special Types of White Blood Cells
• T-Helper Cells activate B-Cells when they detect
  invaders (pathogens)
• B- Cells (B lymphocytes) produce plasma cells
• Plasma cells produce antibodies
• antibodiessubstance that will cling to the
  antigen on the surface of a pathogen an
  immobilize the pathogen or cause them to cling
  together.
• Once infection detected by helper T many plasma
  cells are generated B cells to produce antibodies
• Macrophages (PHAGOCYTES)-engulf and destroy
  immobilized or inactivated pathogens

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Specific Defenses

• Cell Mediated
• Helper T Cells- recognize pathogens and activate
  B cells (Humoral Response) and Cytotoxic (Killer)
  T Cells
• Killer T Cells- Once activated kill pathogen
  directly

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Immunity

• Bodies ability to not become sick against a
  specific invader/pathogen
• It takes a while for plasma cells to figure out
  what antibody will kill a specific pathogen, many
  antibodies are produce in trial and error
  method
• Pathogen causes infection and sickness in
  meantime
• Eventually plasma cells produce an antibody that
  works.
• Special B memory cells remember the correct
  antibody that worked against that specific
  invader
• The next time the invader enters your body the
  Immune system knows how to destroy it before it
  can cause infection or disease.

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Vaccine

• Altered (weakened) form of the real pathogen
  Scientists alter in lab
• No longer capable of causing disease
• Injected in body
• Allows body to recognize and immune system build
  immunity to the pathogen
• When the real pathogen enters body your body is
  already immune (knows how to kill it before it
  can cause infection/sickness)

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Treatments for Diseases

• Bacterial Diseases- bacteria are living things
• Antibiotics-drugs that interfere with the
  chemical processes of living things
• Specifically harm bacterial cells without causing
  harm to us
• Viral Diseases-not living
• Body must defeat on own, no cures

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A.I.D.S and the Body

• AIDS infects and kills Helper T Cells
• Helper T Cells detect pathogens/invaders
• Once enough T Helper are killed by virus the body
  is no longer capable of recognizing invaders
• RESULT- Person becomes seriously infected or sick
  from pathogens that a healthy person may defeat
  rather easily
• Usually die from simple infections
  (cold,flu,pneumonia)