Infection

?
  • Created by: evepoag
  • Created on: 14-10-22 14:55
What is a microorganism?
An organism too small to be seen by the naked eye
1 of 71
What is a pathogen?
Microorganisms that cause disease
2 of 71
What is an infection?
The presence of microorganisms causing damage to body tissue
3 of 71
What is symbiosis?
Relationship which benefits humans and doesn't harm microorganism
4 of 71
What is mutualism?
Relationships which benefit humans and microorganisms
5 of 71
What is commensalism?
Relationships which benefits microorganism and doesn't harm the human
6 of 71
What is pathogenicity?
Relationships which benefit microorganisms and HARMS the human
7 of 71
What is opportunism?
Relationship in which a benign microorganism becomes pathogenic because of decreased human host resistance
8 of 71
Damage to the intestinal tract causes a release of intestinal bacterial into the bloodstream. What can this cause?
Sepsis, shock or death
9 of 71
What are the 4 stages of micro-organism progression (infection)?
This is from the MICROORGANISM perspective
1. Colonisation
2. Invasion
3. Multiplication
4. Spread
10 of 71
During colonisation, what are the 3 ways infectious microorganisms can be transmitted?
1. Direct contact, ie: touching
2. Indirectly via vectors (insects), ie: stings
3. Direct exposure, ie: faecal oral transmutation via food
11 of 71
What are aerosolised microorganism transmissions?
Droplets, ie: sneezing or coughing
12 of 71
What happens when the microorganism is deposited in the receptive environment?
It stabilises adherence to the tissue through receptors
13 of 71
Why do microorganisms adhere?
Protects them from the removal by mechanical forces, eg: coughing mucus
14 of 71
What happens in the invasion stage?
The infectious agent invades surrounding tissues
15 of 71
What happens in the multiplication stage?
The microorganism undergoes rapid multiplication by replicating
16 of 71
How do viral pathogens replicate?
They replicate within the infected cells
17 of 71
How do bacterial pathogens replicate?
They replicate in the macrophages and other cells
18 of 71
What happens in the spread stage?
Some produce localised infections without spread to other regions, whilst others are highly invasive to other areas
19 of 71
What is relied upon for successful spread?
Virulence factors
20 of 71
What happens if the host has an intact immune system?
The microorganism will remain localised
21 of 71
What happens if the host has a compromised immune system?
The infection may spread rapidly
22 of 71
What are the 4 stages of infection? This is from the HUMAN perspective
1. Incubation
2. Prodromal
3. Invasion
4. Convalescence
23 of 71
What happens in the incubation period?
The individual is exposed to the infection. The microorganism has entered the individual and undergone colonisation and has begun multiplying

No symptoms yet - not enough yet
24 of 71
What happens in the prodromal stage?
Initial mild symptoms appear. Activation of the immune system may cause swelling or pain.
Pathogen continues to multiply
25 of 71
What happens in the invasion period?
Pathogen multiplies rapidly, invading further, affecting surrounding tissues

Immune and inflammatory responses are triggered. Symptoms develop and are more obvious and severe
26 of 71
What happens in the convalescence period?
Individual's immune and inflammatory systems have successfully removed infectious agent. Symptoms decline
27 of 71
What are the general symptoms of immune and inflammatory response?
Fatigue, weakness, loss of concentration, general aches, loss of appetite
28 of 71
What is the hallmark symptom of infection?
FEVER
(pyrexia)
29 of 71
How is temperature affected by infection?
Pyrogens (a protein) produce a fever by resetting the hypothalamus thermostat and cause a rise in temperature

It is not a failure to regulate, it is just being regulated at a higher level
30 of 71
What are exogenous pyrogens?
Pyrogens derived from outside the host, eg: bacteria, virus, toxin
31 of 71
What are endogenous pyrogens?
Pyrogens produced inside the body, eg: TNFa
32 of 71
What are the 4 classes of infectious organisms?
1. Bacteria
2. Viruses
3. Fungi
4. Protozoal
33 of 71
What is bacterial infectious organisms characterised by?
No nucleus or mitochondria

They reproduce asexually by simple division of cells
34 of 71
What is important in bacterial proliferation?
It can proliferate rapidly at rates surpassing body's protective responses
35 of 71
What is the body's primary defence mechanism against bacteria?
Antibodies and phagocytes
36 of 71
How does bacteria protect itself against phagocytosis?
they produce thick capsules of carbohydrate or protein around them
37 of 71
What does bacteria produce and what does this do?
Bacteria produces exotoxins which are proteins that protect against inflammation
38 of 71
What are endotoxins and when are they released?
Endotoxins are released during the destruction of bacteria
39 of 71
Pyrogenic bacteria produce these endotoxins.
What do endotoxins do?
They activate inflammatory responses and produce a fever
40 of 71
As the host develops protective antibodies, how does bacteria respond?
Changes antigens and becomes resistant
41 of 71
What is bacteraemia?
Bacteria being transported in the blood due to failure of body's defence mechanisms. These multiple in the blood
This is also called SEPSIS
42 of 71
What is a virus?
A virus is a microorganism that can replicate but only within living cells
43 of 71
How are viral infections transmitted?
One infected individual to an uninfected individual
OR
zoonotic infection (animal to human), ie: through a vector
44 of 71
Name the steps of viral infection transmission?
It attaches to the target cell and penetrates it. It uncoats it, releasing viral nucleic acid (ie: DNA), and replicates it. New particles form and are released into extracellular fluid. The cell continues to make new virus
45 of 71
What are the primary defence mechanisms against viruses?
Antibodies that prevent viral entrance into a cell
AND
Cellular immunity that recognise antigenic changes on surface of infected cell
46 of 71
What are 3 factors of viral infections?
1. They are rapidly dividing - produce large numbers more quickly than immune system can develop
2. Intracellular survival - they hide within cells and away from inflammatory responses
3. Antigenic variation - undergoes frequent antigen shifts
47 of 71
What are fungal infections?
Simple microorganisms that lack the green pigment chlorophyll
48 of 71
What are the characteristics of fungal infections?
They have thick, rigid walls. They may also grow as multi-celled moulds or single-celled yeast
49 of 71
What is it called when you are infected with a fungus?
Mycosis
50 of 71
If fungus invades the skin, hair or nails, what is this called?
Dermatophytes
51 of 71
Itching can be intense. If the tissue breaks, what can this lead to?
Secondary bacterial infection
52 of 71
How are fungal infections transmitted?
Via inhalation or contamination of wounds
53 of 71
Why do fungal infections have intracellular survival?
They can readily adapt to host environment
54 of 71
How do fungal infections suppress the immune responses?
They stimulate to production of immunosuppressive cytokines
55 of 71
What can the fungal infection damage to tissue by secretion of enzymes lead to?
Necrosis
56 of 71
Fungal moulds can secrete what?
Mycotoxins
57 of 71
How can you permit rapid proliferation of fungal infections?
Change in pH and use of antibiotics
58 of 71
What is a parasite?
Any living thing that lives in or on another living organism
59 of 71
What is a protozoa?
A single-celled parasitic organism
60 of 71
What are risk factors for protozoal infections?
Weakened immunity, lack of clean drinking water, contact with contaminated soil
61 of 71
How are protozoal infections predominantly transmitted?
Give an example
Through victors,
eg: transmission of malaria by mosquitoes
62 of 71
What can protozoal infected red blood cells lead to?
Neurological complications, resulting in shock, coma or death
63 of 71
What do antimicrobials do?
They subdue the pathogen once disease process has started. Antibiotics are derived from the microorganism and control the infection by preventing growth/destroying them
64 of 71
Name an antibiotic-resistant microorganism?
MRSA
65 of 71
How do vaccines protect you?
They develop lifelong immunity against a particular pathogen
66 of 71
What is erythema?
Redness of skin
67 of 71
What are immune complexes?
They are complexes formed by the neutralisation of immune molecules
68 of 71
What is it called when an infection occurs in two distinct forms?
Dimorphic
69 of 71
What is antigenic variation?
When bacteria responds by changing antigens and becoming resistant to anitbodies
70 of 71
What is a viron?
The basic viral structure
71 of 71

Other cards in this set

Card 2

Front

What is a pathogen?

Back

Microorganisms that cause disease

Card 3

Front

What is an infection?

Back

Preview of the front of card 3

Card 4

Front

What is symbiosis?

Back

Preview of the front of card 4

Card 5

Front

What is mutualism?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Nursing resources:

See all Nursing resources »See all Anatomy and Physiology resources »