Disease Flashcards
What is health?
Health can be defined as your physical, mental and social wellbeing.
If you’re in good health what are you like?
- free from disease/illness
- have good nutrition - balanced diet
- are suitably housed - with proper sanitation
- well intergrated into society
What is meant by disease?
Disease is defined as a DEPARTURE FROM GOOD HEALTH
A disease is a MALFUNCTION of the body or mind, which causes SYMPTOMS
The symptoms may be PHYSICAL MENTAL SOCIAL
What are parasites?
Parasites are organisms that live on or in another living thing (the host)
What do parasites often gain from their host?
Parasites often grain nutrition/energy from the host
It is this leaching of energy that means parasites may cause damage/disease to the host
Do ALL parasites cause disease?
NO,
NOT ALL PARASITES CAUSE DISEASE
Define what is meant by an external parasite?
Some parasites live ON their host and these parasites are called
External parasites
E.g. Headlice which live in people’s hair
Define the term internal parasite?
Some parasites live IN their host - these parasites are called INTERNAL parasites
E.g. Tapeworms that live in the digestive system
How do parasites benefit from living in/on a host?
Parasites benefit from this relationship with the host by gaining WARMTH, PROTECTION and allows TRANSMISSION/SPREAD to a new host
Is it possible for parasites to live unnoticed by their host?
It is possible for parasites to live unnoticed by their host
It is probably better for a parasite to live unnoticed so that the host doesn’t try to remove it
What can some parasites do?
Some parasites may cause damage that allows other organisms to INVADE the host and cause SECONDARY INFECTIONS
What is a pathogen?
An organism that causes disease
Why are there numerous types of microorganism that are in or on the body?
The human body creates a good habitat in which microorganism can live.
Microorganism = bacteria/viruses/fungi
What will many of the microorganism do that live in the body?
Many microorganism won’t cause harm and may be beneficial
However, pathogens live by TAKING NUTRITION FROM THEIR HOST, but also causing DAMAGE in the process - this can be considerable
What kingdom do bacteria belong to ?
Prokaryotae
Even though bacteria’s have smaller cells than us what can they still do?
Bacteria cells are smaller than ours but they can still reproduce rapidly.
In the right conditions how long does it take some bacteria to divide?
20 Minutes approx.
Why can bacteria be harmful when present in the body?
- their presence can cause disease by damaging cells
Or releasing toxic waste products
Are viruses the smallest microbe?
Yes - They are the smallest microbe.
They are very difficult to see even with an electron microscope
The largest virus is about 0.0000003 mm wide
How do viruses cause disease?
Viruses INVADE cells
Then take over the GENETIC MACHINERY
And other organelles of the cell
They then cause the cell to MANUFACTURE more copies of the VIRUS
The host cell eventually BURSTS releasing many new viruses
What is the name of the fungus that causes Athlete’s foot and ringworm?
Athletes foot and ringworm is caused by TINEA
Where does the fungus live in a host?
The fungus lives in the SKIN
When it sends out reproductive HYPAHE (reproductive fibres)
These hyphae grow out to the surface of the skin to release SPORES
These SPORES cause severe irritation and redness
What else can spores do apart from cause severe irritation and redness?
Spores can travel though the air and affect other people
What are protoctista (Protozoa)
Protozoa are single-celled organisms
They are not classified as bacteria or any other group as theyre their own group.
Give examples of diseases caused by animal-lie protoctista?
- ameboid dysentery and malaria
How do Protozoa usually cause harm?
- protoctista usually cause harm by ENTERING HOST CELLS and FEEDING ON THE CONTENTS as they grow
E.g. The malaria parasite has immature forms that feed on the contents of red blood cells
What must a pathogen do in order to cause disease?
- travel from one host to another
- get into the host’s tissues
- reproduce
- cause damage to the host’s tissues and leave host tissue’s
Is there only one way in which diseases can be transmitted from one individual to another?
NO There are lots of different ways in which disease can be transmitted from one individual to another
What types of transmission are there?
Direct
Indirect transmission
Define what is meant by direct transmission?
Direct transmission is the passing of a pathogen from host to new host with no intermediary.
Give 4 examples of disease transmission through direct transmission?
- direct contact (touch)
- faecal-oral transmission
- droplet infection
- spores
Examples of diseases transmitted through touch - direct contact?
HIV
Ringworm
Examples of diseases transmitted through faecal-oral transmission?
- cholera
- Salmonella
Diseases transmitted through droplet infection?
- TB
- influenza
Disease transmitted through spores?
Tetanus
Anthrax
Define indirect transmission?
- this is the passing of a pathogen from host to new host via a vector
What is a vector?
A vector is another organism that may be used by the pathogen to gain entry into the primary host/
What climates do many bacteria, protoctists and fungi grow and reproduce best in?
Bacteria reproduce more in warm and moist conditions - tropical diseases
List the social factors which affect the transmission of diseases
- overcrowding - many people living and sleeping together in one house
- poor ventilation
- poor health
- poor diet
- homelessness
- living and working with people who have migrated from areas where a disease is more common e.g. Nurses or doctors or people from tropical countries
