pathogens

How do pathogens transmit

Sexual intercourse, animal bites, dirty water, undercooked food, vectors

Factors affecting trasmission

Climate, living conditions and social factors

Climate

Rainfall, temperature and humidity

Living conditions

Diet, ventilation, sanitation and overcrowding

Social factors

Access to good healthcare, level of health education

Types of pathogens

Fungi, bacteria, viruses and procratists

Fungi

Saprophytic, hyphae prematurities surfaces and produces spores/toxins that digest the cell

Human dieselise caused by fungi

Ring worm and athlete’s foot

Plant diseases caused by fungi

Black Sigatoka

Bacteria

Single celled cells with no nucleus that reproduce rapidly

Disease caused by bacteria in humans

Tuberculosis, bacterial meningitis and salmonella

Diseases cauśed by bacteria in plants

Ring rot

Viruses

The smallest type of pathogen which is non-living and hijacks cells to reproduce in them until they can burst out

Diseases caused by viruses in humans

HIV/Aids and influenza

Diseases caused by viruses in plants

Tobacco mosaic virus

Protacist

The largest pathogen and contains a nucleus

Diseases caused by protacist in humans

Malaria

Diseases caused by procratists in plants

Potatoes blight

Phytoalexins

A chemical produced by some plants that inhibits the growth of fungi and other pathogens

Saponins

A chemical produced by some plants that destroys the cell membrane of fungi and other pathogens

Waxy cuticles

Present on stems and leaves to provide a physical barrier to pathogens. May also stop water collecting On-The-Go leaf reducing the likelihood of the pathogens transmitted via water

Cell walls

Provide a physical barrier to pathogens that make it last the waxy cuticle

Callose

A polysaccharide produced by plants that gets deposited between cell walls and plasma membranes during infection to make it harder for pathogens to enter cells. Callose may also be deposited in the plasmodesmata to limit the spread of viruses

Other plant chemicals

,any be toxic to insects reducing the amount of insect feeding on the plant reducing the risk of disease transmission via vectors

Skin

Acts as a physical barrier to pathogens and a chemical barrier by producing antibacterial chemicals

Oelic acid

Kills bacteria

Fatty acids

Lowers the skin pH creating a more acidic environment making it harder for pathogens to colonise

Secretion of lysosomes

Catalyse the break down of carbohydrates which is the main component of the cell walls of bacteria

Secretion of sebum

Limits bacterial growing

Skin repair

The skin is able to repair itself by the outer layer of the skin cells dividing and migrating to the edges of the wound. The tissue below then contracts to bring the edges of the wound together. The repair is then made by collagen fibres for strength but using too many causes scarring

Platlets

For, scabs via blood clots that plug the wound together prevent pathogen entry. This occurs due to a series of chemical reactions when platelets are exposed to damage

Stomach

Secretes hydrochloride acid which kills bacteria

Urethra

Flow of urine prevents the growth of bacteria

Inflammation

Swelling triggered by tissue damage as it releases molecules which increase the permeability of the blood vessels causing the, to leak fluid to the surrounding tissue. Helps isolate any pathogens that may have entered

Expulsion reflexes

Coughing and sneezing that occur when the mucosal membrane is triggered by dirt/ dust to enable the body to expel foreign objects