Immune System

Raffaele Nardella

Pathogens1. Bacteria

• microscopic organism -> cholera2. Viruses

• genetic material -> flu3. Fungi

• moulds and mushrooms -> athlete’s foot4. Protozoa

• single-celled organism -> infections• parasites -> malaria

Raffaele Nardella

Other causes of disease1. Vitamin deficiency

• scurvy

2. Mineral deficiency• anaemia

3. Disorders of the body• cancer - diabetes

4. Inherited deficiency• red-green colour vision deficiency

Raffaele Nardella

Body defences1. Skin

• physical damage - microbe infection - dehydration2. Blod clotting

• scab -> platelets - fibrin3.Mucous membranes

• respiratory system• nasal hairs -> keep out dust and microorganism• sticky mucus -> traps them• cilia -> carries them away

4. Stomach acid• hydrocloric acid

Raffaele Nardella

Immunity

Pathogens reproduce

cell damage (viruses) - toxins (bacteria)

Symptoms of infectious diseases

Raffaele Nardella

Immune systemWhite blood cells (lymphocytes):• Engulfing pathogens• Producing antitoxins• Producing antibodies:

proteins with chemical fit to antigensmeeting antigens

copies of antibodiesdestroying pathogens

Active immunity -> natural reproduction of antibodies

Passive immunity -> injection

Raffaele Nardella

ImmunisationVaccination -> inactive pathogen into the bodyVaccines:

• live pathogens• fragments of pathogens• toxins• dead pathogens

Acting as antigens -> white blood cell -> antibodies

Raffaele Nardella