M23. Disease p1 Flashcards Preview

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What is meant by the word health?

a state of mental, physical and social wellbeing, and the absence of disease


What is disease?

a departure from good health caused by a malfunction of the mind or body, which causes symptoms- which can be physical, mental or social


What is a parasite?

an organism that lives in or on another living thing, causing harm to its host.


What is a pathogen?

an organism that causes disease


Give 6 examples of states that define you're in good health

- free from disease
-able to carry out normal, physical and mental tasks expected in modern society
- well fed, with a balanced diet
- usually happy, with a positive outlook
- suitably housed with proper sanitation
- well integrated into society


How do parasites usually harm their host

By taking their nutrition from the host


Whats the difference between an internal and external parasite, give an example of each

external, live on the host eg head louse
internal, live IN the host eg tape worms


Why do some parasites live unnoticed, and what causes them to become noticable?

So that the host does not try to remove it
when the parasites become too numerous


Why are there so many types of organisms that live on and in humans?

As the human body creates a good habitat in which they can live


How do pathogens survive?

By taking nutrition from their host, but also cause damage at the same time.


Which kingdom does bacteria belong to?



What makes bacteria so destructive

As although their cells are smaller than ours, they can reproduce rapidly- as quickly as every 20 minutes in the ideal conditions, and their presence causes disease by damaging cells or producing waste products that are toxic to us.


What is Cholera caused by?

The bacteria Vibrio cholerae


What is tuberculosis caused by? (TB)

two species of bacterium, Mycobacterium tuberculosis and Mycobacterium bovis.


What can the fungus Tinea cause?

athletes foot and ringworm


Give 2 examples of well known illnesses and a disease that viruses cause

the common cold and influenza


How do cells do their damage?

They invade cells and 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 must a pathogen be able to do to cause a disease?

-travel from one host to another
-get into the hosts tissue
-cause damage to the hosts tissues


What must a pathogen over come when entering the body, before it can begin reproducing

the primary, secondary and immune response systems


What are the most common forms of transmission?

- by means of a vector
- by physical contact
- by droplet infection


What is malaria caused by/.

a eukratic organism from the genus Plasmodium, it can be many types- Plasmodium falciparum is the most widespread but there is also Plasmodium vivax, ovale and malariae


How is malaria spread?

by a vector- the females Anopheles mosquito carries the plasmodium from an infected person to an uninfected person.
They have mouthparts that are adapted as a fine tube or proboscis which is used to penetrate a blood vessel and withdraw blood.


Where do the malarial parasites live in the body and what do they feed on?

The Malarial parasites live in the red blood cells of a human host and feed on haemoglobin


Describe the 7 stages of malarial transmission

- person with malaria has gametes of plasmodium in the blood
- female anopheles mosquito sucks blood, the gametes fuse and zygotes develop
- plasmodium develops and migrates to mosquitoes salivary glands
- this mosquito bites uninfected person
- plasmodium migrates to liver
-plasmodium migrates to the blood
-person now has malaria.


Apart from mosquitoes, how else can malaria be transferred?

by careless unhygienic medical practices, eg unscreened blood transfusions and use of unsterilised needles.
It can also be passed into the placenta of an unborn child.


What is AIDs caused by?

the human immunodeficiency virus which enters the body and remains unactive (known as being HIV-positive) But once it because active, it destroys the t helper cells in the imune system.


How does HIV work?

it enters the body and remains unactive (known as being HIV-positive) But once it because active, it destroys the t helper cells in the imune system. This stops these cells from preventing infection, so your immune system is less successful so you may contract a range of oppertunistic infections, which can lead to your death.


What does AIDS stand for?

acquired immune deficiency syndrome.


How can HIV be transmitted?

-exchange of body fluids, eg blood to blood contact.
- unprotected sex
-unscreened blood transfusions
- use of unsterilised surgical equipment
- sharing hypodermic needles
-accidents such as 'needle-stick'
- across the placenta or during child birth
- from mother to baby during breast feeding


What is TB caused by?

2 types of bacterium, Mycobacerium tuberculosis and Mycobacterium bovis.