Module 4: Disease and the Immune system Flashcards
What is a disease?
A condition that impairs the normal functioning of an organism.
What is a communicable disease?
A disease that spreads from organism to organism.
Name an animal disease caused by bacteria.
•tuberculosis
•bacterial meningitis
Name a plant disease caused by bacteria.
Ring rot
(potatoes, tomatoes)
Name an animal disease caused by fungi.
•ringworm
•athlete’s foot
Name a plant disease caused by fungi.
Black Sigatoka
(banana plants)
Name a disease in plants caused by protoctista.
Potato/tomato late blight.
Name an animal disease caused by protoctista.
Malaria
Name a plant disease caused by a virus.
Tobacco mosaic virus
Name an animal disease caused by a virus.
•HIV/AIDs
•influenza
Give an example of direct transmission.
Droplet transmission (coughing/sneezing).
What is direct transmission?
When the pathogen is spread directly from one organism to another.
What is indirect transmission?
When the pathogen is spread though something else.
Give an example of indirect transmission.
Though air, water, food.
What is a vector?
Anything that carries the pathogen from one host to the next.
What is a non-specific defence?
Something that prevents pathogens entering the body. They are the same for all pathogens.
Give some examples of non-specific defences in humans.
*skin
*mucous membranes
*tears
*stomach acid
*blood clotting
*wound repair
*expulsive reflexes
*inflammation
How does the skin act as a defence against pathogens?
*physical barrier
*layer of dead skin cells - hard for pathogens to penetrate
*sebaceous glands secrete sebum (slightly acidic) - prevents growth of harmful bacteria
*covered with harmless microorganisms - compete for resources - reduce growth of pathogens
What are lysozymes?
Enzymes that destroy bacteria by digesting their cell walls.
How do mucous membranes act as a defence against pathogens?
*line openings
*secrete mucous - traps microorganisms to be destroyed by phagocytes
*contain lysozymes
How do tears act as a defence against pathogens?
They contain lysozymes.
How does the stomach acid act as a defence against pathogens?
Hydrochloric acid kills pathogen’s in food and water - pH too high.
What are expulsive reflexes?
The body’s automatic responses to irritation to remove foreign bodies.
Give some examples of expulsive reflexes.
*sneezing
*coughing
*vomiting
*diarhhoea