Diseases and immunity 

{{==Pathogens== are disease causing organism{{

{{==Transmissible diseases== where a pathogen can be transmitted form one host to another{{

Pathogens can be transmitted through direct and indirect contact and indirect contact

Direct contact:

When diseases are transmitted through blood or body fluids

Indirect contact:

  • Through air droplets that contain the pathogens
  • If a surface is contaminated with the pathogen and a person comes in contact with that surface they can become infected
  • Animals such as mosquitoes act as vectors and transmit the diseases to us
  • Food that isn’t properly cooked or cleaned can infect us

Our body protects us against pathogens by different defense:

  • skin: if the skin is broken platelets form blood clots to seal the wound so that no pathogen can enter
  • Nose: nose hairs traps any pathogens that might enter through our nose
  • Eyes: our eyes produce lysozyme to prevent or kill any pathogen that might enter through our eyes
  • Trachea: our trachea contains goblet cells that produce mucus which traps the pathogen . Cilia moves the mucus out of the airway
  • Stomach acid: our stomach acid can kill any pathogen that might have entered in the digestive system
  • White blood cells : once a person is infected white blood cells produce lymphocytes and phagocytosis to kill the pathogen

{{Active immunity is a defense against pathogens by producing antibodies it is gained by being infected by a pathogen or after getting a vaccine{{

[[Each pathogen has a specific antigen which has its own specific shape lymphocytes produce antibodies which have a complementary shape to that specific antigen antibodies then lock on / bind the antigens to kill it or to mark it for phagocytes to engulf them out digest them with the help of enzymes.[[

[[Antibodies are proteins[[

[[Memory cells recognize a specific pathogen and make the immune response much faster when the body is infected with that specific pathogen again.[[

How do vaccines affect immune system(active immunity)

[[Dead or weakened pathogens are injected into the body. The antigens in the pathogen triggers production of antibodies lymphocytes then produce antibodies. Memory cells are also produced for long term immunity.[[

[[Vaccines help more people become immune to a specific pathogen which might prevent an outbreak.[[

{{==Passive immunity ==is short term immunity that is caused by getting antibodies from an individual or vaccine{{

[[Babies get antibodies from their mothers placenta and breast milk[[

[[Breast feeding is important for newborns because they can get passive immunity from their mothers antibodies which allows them to have a short term immunity towards pathogens[[

CHOLREA

Cholera is a bacterium caused by contaminated food or water

Symptoms of cholera:

  • dehydration
  • Lose of ions and water in blood
  • Diarrhoea

[[CHOLREA bacteria is digested and multiple.the bacteria is them attached to the walls of the canal . The bacteria releases a toxin this toxin causes chloride ions to be released . Release of ions makes water go into the lumen by osmosis . Fewer water and chloride ions are in the blood .[[

Treatments of CHOLREA

Oral rehydration: where you drink water with sugar and salt

Vaccines