Malfunctions of the Immune System, Pathogens

1
Malfunctions of the Immune System, Pathogens
Immunity
2
Immune System Malfunction

• The immune system can cause two very serious
  problems if it is not working properly
• Inappropriate attacks against non-threatening
  agents (Allergies).
• Immune-deficiency diseases (AIDS).
• Allergies
• An allergy occurs when your immune system
  mistakes harmless cells for harmful invaders.
  Something harmless, like peanuts, mobilizes an
  antibody strike. Increased tissue swelling and
  mucous secretion, and sometimes constricted air
  passages are all a part of this response.

3
Allergic Response

• When you come into contact with the vicious
  peanut, your cells perceive they are in danger
  and release a chemical signal called bradykinin
  which triggers the release of another chemical
  signal called histamine.
• Histamine is produced by the basophils (a type of
  white blood cell) and it changes the cells of the
  capillaries increases their size and
  permeability. Proteins and white blood cells can
  leave the capillary in search of the invader
  and alter the osmotic pressure in the blood
  vessel this causes the swelling.
• Drugs such called antihistamines are used to try
  and block their release and action.

4
Autoimmune Disease

• The immune system can go awry and recognize the
  bodys own cells as invaders or foreign entities.
  This could result in an attack being launched by
  you against yourself.
• Renegade T cells and B cells are the problem
  they do the recognizing and attacking. They can
  be held in check by suppressor T cells that
  recognize these renegades and intercept them
  before they can do any damage, but, if the
  suppressor T cells do not stop them they break
  the body down. This can be seen in such diseases
  as rheumatoid arthritis, type 1 diabetes and
  lupus.
• The suppressor T cells can be weakened by drugs
  or serious infections and this may open you up to
  autoimmune diseases.
• Drugs exist that help lessen the intensity of the
  renegade T and B cell attacks.

5
Pathogens Disease

• A pathogen is any organism or entity that causes
  disease within the body.
• Pathogens may include bacteria, viruses, prions
  and a wide variety of parasites both protists
  and animals.
• Many diseases are believed to have originated in
  domestic animals and, through random mutation,
  become communicable to humans. When a disease is
  considered for its pathogenic capabilities, both
  the virulence and transmissibility of the disease
  are examined.

6
Pathogens

• Bacteria
• Viruses
• A.I.D.S. Virus
• Giardia lamblia a protist parasite.
• Plasmodium vivax protist malaria.
• Trichinella worm trichinosis.

7
How To Get Sick

• Pathogens are transmitted through a variety of
  methods.
• Droplet Infection A sneeze or cough can put out
  thousands of water droplets that each contain
  many microbes. These droplets can be inhaled or
  introduced directly to the body through food
  water or skin contact.
• Waterborne Some infections must enter the body
  through water or they dry out and die quite
  quickly. The most common cause of waterborne
  infections is unsanitary disposal of waste near a
  water collecting area that is used for drinking.
• Direct Contact These infections are slower
  spreading and can be avoided if the proper
  precaution is taken. Methods of introduction
  include animal bites, unsanitary food
  preparation, sexual contact and drug use with
  unclean syringes.
• Vectors A vector is a disease-carrying animal
  (usually an insect) that picks up the microbes by
  hanging out near waste that may be contaminated.
  They then transfer these microbes when they come
  into contact with you. Lice, ticks, fleas and
  mosquitoes are all excellent vectors.

8
Induced Immunity

• Induced immunity is an immune response brought
  about by intervention from ones own body or form
  an outside source. There are two forms of induced
  immunity active immunity and passive immunity
  both are common.
• Active Immunity is gained when your own inner
  workings produce antibodies against an invading
  pathogen. Active immunity lasts a lifetime.
• Passive Immunity is protection (antibodies or an
  inducer of antibody formation) that is introduced
  into the body from an outside source such as a
  vaccination. Passive immunity is often only
  temporary in its effectiveness.

9
Vaccination

• A vaccine is an antigen-containing substance that
  can be swallowed or injected to provide continued
  immunity to a specific disease/pathogen.
• The vaccine usually contains a weakened or dead
  form of the pathogen it is meant to target. The
  body can now produce antibodies against this
  weak/dead pathogen so when the full-strength
  invader enters the body, it has a defense ready
  to combat it. Many vaccines have to receive
  boosters occasionally to keep up their strength.
• Labs are now developing genetically modified
  forms of vaccines that can target specific
  pathogens and bring about the immune response in
  an attempt to keep up with their somewhat rapid
  evolution.

10
Vaccination
11
Chemical Controls

• Certain chemicals can target specific pathogens
  and kill them by not allowing them to carry out
  the reactions necessary to survive.
• Antibiotics are chemicals that are obtained from
  living things that are toxic to other living
  things often used against predators, prey or
  the competition.
• Penicillin was discovered by Alexander Fleming
  when mould had contaminated an experiment
  involving bacteria. He was awarded the Nobel
  Prize in Medicine.
• Penicillin interferes with bacterial cell walls
  they become thin and eventually burst under the
  pressure of the cells own cytoplasm.

12
Antibiotic Resistance

• Bacteria can reproduce asexually at a frightening
  rate 20 minutes if conditions are optimal.
• Mutation may occur each time they multiply
  usually it is 1 mutant per 200 bacteria. A
  spoonful of dirt may contain over a billion
  bacteria this would yield about 5 million
  mutants.
• Some of these mutations give the bacteria the
  ability to resist certain antibiotics.
• Canadian hospitals have had bouts with
  Clostridium difficile a bacteria that infects
  the colon and releases a toxin inside the body.
  It has developed a resistance to many antibiotics.

13
Sharing A Problem

• Bacteria can carry out a process called
  conjugation with another bacterial cell.
• During conjugation, the bacteria form a tube
  (called a sex pilus) between themselves and
  exchange copies of their genetic information
  called plasmids. These plasmids are the extra
  pieces of DNA that often house the genes for
  resistance.
• The result may be
• Bacteria becoming more resistant as the plasmid
  is shared throughout the colony.
• Bacteria trading plasmids and, in doing so,
  trading resistance genes that will see them
  become super bugs.

14
Conjugal Visits?
15

• FIN