B2 health and disease and how disease spreads Flashcards
What is a disease?
A condition that commonly damages the cells of the host and impairs the normal structures or functioning of an organism.
Causes of disease (5)
Infected by pathogen Mutation in organisms genes Affected by environmental conditions (eg a plant gets insufficient light) May experience trauma Lifestyle
What is a Communicable disease?
A disease that can be spread among organisms
What causes communicable diseases?
Pathogens infecting the organism
What is a pathogen?
A microorganism that causes disease
Types of Pathogens (4)
Bacteria, viruses, fungi, protists
What is a Non-communicable disease?
Cannot be passed from one organism to another.
Generally long lasting and progress slowly
Non-communicable disease (4)
Cancer, diabetes, cardiovascular disease, respiratory disease
What are the causes of Non-communicable diseases?
Associated with genetic mutations, lifestyle and environmental factors
What is a symptom?
Changes in an organism that indicate a disease is present.
Example of a symptom of Multiple Sclerosis
Temporary loss of vision
What is an incubation period?
Time from infection to the show of symptoms
What is the incubation period for chicken pox?
14 day for spots to appear
What is HPV (Human Papillomavirus)?
Virus that effect the reproductive system
Doesn’t always cause symptoms often clears up on it’s own
Can cause cell Change resulting in the development of certain types of cancer.
Though that all cervical cancer are result from HPV infection
What are Helminths?
A certain type of worms that causes disease if they get inside the body
What is Trichinosis?
A disease that is caused by infection by the Helminth
It can reduce the development of some autoimmune diseases e.g. Crohns
What is an autoimmune disease?
The immune system recognises the bodies own cells as foreign and attacks them.
Bacteria
Very small (1/100 of the size of a body cell).
Reproduce rapidly
Produces toxins that damage the cells and tissues.
Viruses
Not cells
Really tiny (1/100 the size of a bacterium)
Replicate inside the infected organism’s cells, the cell then burst releasing the viruses.
Protists
Eukaryotic
Single celled
Vary in size
Fungi
Some fungi are single celled whilst others have a body that is made up of thread like structures called hyphae.
These can grow and penetrate human skin and the surface of plants and cause disease. They produce spores spreading the disease
What are hyphae?
Thread like structures that make up the fungi body
How are communicable disease transmitted? (7)
Air, water, surfaces (touch), body fluid, animal vectors, soil, food.
How are communicable spread by water?
Drinking or bathing in dirty water
Cholera causes diarrhoea and dehydration.
Spread from the diarrhoea from other suffers.
How are communicable disease spread through the air?
Droplets produced when you cough or sneeze others breath in.
E.g flu/influenza
In plants it can be transmitted through the wind.
E.g. Chalara ash dieback
How are communicable disease spread on surfaces?
Som pathogens can be picked up by touching contaminated surfaces.
E.g. TMV (Tobacco Mosaic Virus) make the leaves of tomato plants mottled and discoloured effecting photosynthesis effecting the growth. Spread through infected leaves rubbing against healthy leaves
Athletes foot. Fungal disease which makes the skin on feet itch and flake off. Passed through touching the same surfaces as an infected person.
How are communicable disease spread through body fluids? 3
Blood: sharing needles, contaminated blood transfusion
Breast milk
Semen: unprotected sex (STD/STI) e.g. HIV
HIV initial flu like symptoms then no symptoms for several years
Enters the lymph system and attacks the immune cell (AIDS)
How are communicable diseases spread by animal vectors?
Animals vectors are animals that spread disease e.g. a mosquito with malaria. Caused by a protist. Part of the life cycle of the protist takes place inside the mosquito.
The mosquito picks up the protist when feeding on an infected animal then passes it on by inserting the protist in to the animals blood vessel when feeding
Malaria causes repeating episodes of fever and can be fatal
How are communicable disease transmitted in soil?
Some pathogen can live in soil so plants that live in the soil can get infected.
Bacteria that causes crown gall disease are able to live freely in soil and the roots of some plants. If the plant get’s infected it can get growths or tumours called galls
The galls can damage plant tissue, restricting the flow of water. The plant becomes weaker and may die
How are communicable disease transmitted through food?
By eating contaminated food.
Salmonella is an example of this. If the food isn’t cooked properly or kept too long then Bactria can infect it.
