4.1 - Communicable Disease, Prevention And The Immune System Flashcards
What is a disease?
It is a condition that impairs the normal function of an organism
What is a pathogen?
An organism that can cause disease
What are the 4 types of pathogens?
Bacteria, viruses, fungi, protist
What is a communicable disease?
A disease that is able to spread between organisms
What pathogen causes tuberculosis?
Bacterium
What pathogen causes bacterial meningitis?
Bacterium
What causes ring rot?
Bacterium
What causes HIV/AIDS?
Virus
What causes influenza?
Virus
What causes tobacco mosaic virus?
Virus
What causes black sigatoka?
Fungus
What causes ringworm?
Fungus
What causes athletes foot?
Fungus
What causes tomato/potato late blight?
Protist
What causes malaria?
Protist
What are the 7 diseases that affect humans and animals?
- tuberculosis
- bacterial meningitis
- HIV and AIDS
- influenza
- ringworm
- athletes foot
- malaria
What are the 4 diseases that affect plants?
- ring rot
- tobacco mosaic virus
- black sigatoka
- late blight
What are the 2 ways that a disease can be transmitted?
Directly and indirectly
What is direct transmition?
When the disease is transmitted directly from one organism to another
What are 3 ways that disease can be directly transmitted?
- droplet infection
- sexual intercourse
- touching
What is indirect transition?
When a disease is transmitted from one organism to another via an intermediate
What are 4 ways that a disease can be indirectly transmitted?
- air
- water
-food - vector
How can overcrowding affect disease transmission?
TB is spread by droplet infection and can also be spread indirectly because the bacteria can remain in the air for long periods of time and when there is an increased amount of people there will be higher infection rates
How can the climate affect disease transmission?
Malaria is more common in tropical countries which are hot and humid, this is because these are ideal conditions for mosquitoes to breed
How do social factors affect disease transmission?
Transmission rates are higher in areas that have limited access to good healthcare and good healthcare education
What are the 7 primary defences that humans and animals have?
- skin
- mucous membranes
- blood clotting
- inflammation
- eyes
- ears
- expensive reflexes
How does the skin work as a primary defence against disease?
It acts as a physical barrier blocking pathogens from entering the body. It can also acts as a chemical barrier by producing chemicals that anti microbial and can inhibit the growth of pathogens
How does a mucus membrane act as a primary defence against disease?
They protect the body openings that are exposed to the environment, by the membranes secreting mucus to trap pathogens
How does blood clotting act as a primary defence against pathogens?
Blood clots plug wounds to prevent pathogen entry and blood loss
How does expulsive reflexes act as a primary defence against disease?
Coughing and sneezing is caused by irritation in the respiring tract or the mucus membranes, this then expels the pathogen
How does the eyes act as a primary defence against disease?
Tears are composed of water, salt, antibodies and lysosomes and the lysosomes destroy the microorganisms by breaking down the cell walls so that they can’t reproduce
How do the ears act as a primary defence against disease?
The ear canal is lined with ear wax to trap foreign pathogens
Define the term passive defence?
A defence mechanism that is present at all times
Define the term active defence?
A defence that occurs when a pathogen is detected
What are the 2 types of active defences that a plant has?
Physical and chemical
How is the waxy cuticle work as a physical defence?
It is a physical barrier that stop pathogens entering and water which may be carrying pathogens
How does the cell wall in a plant work as a physical defence?
It acts as a barrier against pathogens if they were to get past the waxy cuticle
How does callose act as a physical barrier in plants?
It is a polysaccharide that is deposited between plant walls and the membrane during times of stress so it is harder for pathogens to enter and limits the spread of viruses by block the plasmodesmarta
How do anti microbial chemicals work in plants as a chemical defence?
They either kill the pathogens or inhibit them. Saponins destroy the cell membrane of fungi and phytoalexins inhibit the growth of fungi. They also secrete toxins to stop insect feeding to limit the spread by vectors
How does inflammation work?
The body releases a molecule to increase the permeability of the blood vessels so they can leak fluids surrounding the damaged tissues to isolate any pathogens that may have entered. This also causes vasodilation so it increases blood flow to get more WBC to the area
