Module 4.1.1 - Communicable diseases Flashcards
What is a disease?
Condition that impairs normal function if an organism
What is a pathogen?
Microorganism that causes disease
What is a communicable disease?
Disease spread from person to person
What are communicable diseases caused by?
Pathogen
What does tuberculosis affect and caused by?
Animals/human/cattle
- bacterium
What does bacterial meningitis affect and caused by?
Humans
- bacterium
What does ring rot affect and caused by?
Potatoes/tomatoes
- bacterium
What does AIDS/HIV affect and caused by?
Humans
- virus
What does tobacco mosaic virus affect and caused by?
Plants
- virus
What does influenza affect and caused by?
Animals/humans
- virus
What does black sigatoka affect and caused by?
Banana plants
- fungus
What does ringworm affect and caused by?
Cattle
- fungus
What does athlete’s foot affect and caused by?
Humans
- fungus
What does potato/tomato blight affect and caused by?
Potatoes/tomatoes
- Protoctista
What does malaria affect and caused by?
Animals/humans
- Protoctista
What is direct transmission of disease?
Transmitted directly from one organism to another
- can be transmitted through droplet infection, sexual intercourse and touching infected organism
What are examples of direct transmitted diseases?
- HIV transmitted between humans or from mother to unborn child via placenta
- athlete’s foot via touch
What is indirect transmission of disease?
Transmitted from one organism to another via an intermediate
- can be transmitted through air, water, food, vector
What are examples of indirect transmitted diseases?
- potato/tomato late blight, spores carried between plants, in air then water
- malaria spread between humans via mosquitos (vectors), carry it and spread it
What factors affect transmission of diseases?
Living conditions - overcrowded will have more chance of spread
Social factors - income/occupation/area?
Climate - wind/water/heat can affect the spread
What are the 6 animal defences?
- skin
- mucous membranes
- blood clotting
- inflammation
- wound repair
- expulsive reflexes
What do pathogens need to cause disease?
Need to enter an organism
What is the mucous membrane defence?
Protects body openings exposed to environment, some membranes secrete mucous
What is the animal skin defence?
Physical and chemical barrier, blocks pathogens from entering, produces chemicals that are antimicrobial, can lower pH which inhibits growth of pathogens
What is the animal blood clotting defence?
Mesh of protein fibers, plug wounds to prevent pathogen entry and blood loss, formed by chemical reactions in body that take place when platelets are exposed to damaged blood vessels
What is the animal inflammation defence?
Signs include swelling, pain, heat and redness, can be triggered by tissue damage, causes swelling and helps isolate any pathogens that may have entered damaged tissue, molecules cause vasodilation which increases flow to affected area, makes area hot and bring white blood cells to area to fight off any pathogens
What is the animal wound-repair defence?
Skin is able to repair itself in event of injury and reform barrier against pathogen entry, surface is repaired by outer layer of skin cells dividing and migrating to edges of wound, tissue below wound contracts to bring edge of wound closer together, repaired using collagen fibers - too many collagen fibers form a scar
What is the animal expulsive reflexes defence?
Includes coughing and sneezing, sneeze happens when mucous membranes in nostrils are irritated by dust/dirt, cough stems from irritation in respiratory tract, both an attempt to exert foreign objects/pathogens, happen automatically
What are the 3 plant defences?
- physical
- barrier
- chemical
What is a physical plant defence?
Most have waxy cuticle which protects against pathogen entry, also stops water collecting on leaf, reduces risk of infection by pathogens that’re transferred between plants in water, cell walls forms a barrier against pathogens that make it past waxy cuticle, plants produce polysaccharide called glucose, callose gets deposited between plant cell walls and plasma membranes during times of stress
What is a barrier plant defence?
Callose deposition may make it harder for pathogens to enter cell, at plasmodesmata may limit spread of viruses between cells
What is a chemical plant defence?
Plants produce antimicrobial chemical which kills pathogens or inhibits their growth, other chemicals secreted are toxic, reduces amount of insect feeding on plants, reduces risk of infection by plant viruses caused by insect vectors
What is the immune system?
Body’s reaction to foreign antigens
When does the immune system respond?
If pathogens gets past primary defense