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Biology U4 > Y.7 Invading The Body > Flashcards

Y.7 Invading The Body Flashcards

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1
Q

How pathogens Exeter the body?

A

1) cuts in skin
2) through the digestive system via contaminated food or drinks
3) through the respiratory system or by inhaling
4) through the mucosal surface eg inside the nose , mouth and genitals

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2
Q

How does stomach acid help with barrier

A

Provide acidic environment and that is unfavourable to many pathogens to survive

*however some may survive and travel to intestine where they infect the gut wall cells and cause disease

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3
Q

How does the gut and skin flora help with barrier

A

The intestine and skin is covered in harmless microorganisms (flora)

They compete with pathogens for nutrients and Space this limits the number of pathogens living in the gut and on the skin and makes it harder for them to infect

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4
Q

How does the skin prevent infection

A

Skin acts as a physical barrier
—> if damage pathogens can enter to the bloodstream

The blood clots the Area of damage to prevent pathogens from entering but may get in before the clot

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5
Q

How does lysozyme help with

A

Musocsal surfaces (eyes,mouth and nose) produce secretion (tears, saliva and mucus) these secretion all contain enzyme called lysozyme . Lysozyme kill bacteria by damaging their cell wall makes the bacteria burst open (lyse)

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6
Q

How does vector works

A

Living organism carry the pathogens and transmit them between hosts

—> insects such as flies and mosquitoes are common vector for disease

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7
Q

How does inhalation work in invading the body

A

Droplets from respiratory tract will suspended in the air when an infected person coughs, sneezes or talks

These droplets contain pathogens that can be inhaled by healthy people

The airway provide an entry point into the respiratory system of a new host and another infection occurs

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8
Q

How does ingestion invade the body

A

Pathogen can enter through the digestive system when we ingest contaminated food or drink

If food is undercooked as heat destroyed most of the pathogens
These pathogens can make their way through the lining of the gut and cause disease

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9
Q

How does indirect contact can invade the body

A

Inanimate objects can contain large number of pathogens that may be transferred between host

An infect individual may touch or cough on an object which is later touched by a healthy individual who transfer the pathogens to their mouth or node by touching their face

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10
Q

How does inoculation invade the body

A

Pathogens enter through broken skin providing it with a direct route into the blood stream

Transmission could be through sexual contact sharing a needle during drug use or bites or scratches from infected animal

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11
Q

How does direct contact invade the body

A

Pathogens that spread this way will require some part of the host to come into direct contact with a healthy individual

Pathogen that spread by this route can then pass through the mucous membrane and enter the blood stream

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12
Q

How does sebum help

A

Oily substance which contain chemical substance that inhibit growth of infectious microorganisms

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13
Q

What are endotoxins

A

Lipopolysaccharides that are integral part of the outer layer of the cell wall of the gram negative bacteria

Act as a toxin to other cells

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14
Q

How to endotoxins work

A

The lipopolysaccharides that are an integral part of the outer cell wall of the gram negative bacteria

The polysaccharide stimulate the immune response. The effects happens mainly around the bacteria itself and not directly fatal

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15
Q

What are exotoxins

A

Soluble proteins produced and released into the body by the bacteria as they metabolise and reproduce in then cells of their host : these proteins act as toxins in different ways

Directly fatal

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16
Q

What are host tissue invasion

A

The bacteria directly attacks the tissue and cells of the host and is linked to the production of endotoxins and exotoxins

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17
Q

What is tuberculosis

A

Communicable disease

Affects and destroy the lungs and it’s tissue and supremes the immune system making it less able to fight against the disease

Spread in form of droplets

18
Q

Primary infection

A

Bacteria is inhaled into the lungs and slowly multiply causing no symptoms

If the immune system is fully active it will cause the localised inflammatory response engulfing the bacteria and farming a mass of tissue called TUBERCULE

After a while the inflammation would fully disappear and lungs heal

19
Q

Active stage

A

Some bacteria are able to survive past the primary infection stage as they have adapt which allows them to do so

Allowing them to remain dormant and reproduce until the immune system weakens

They will then cause active tuberculosis

The most effective bacteria are selected to pass their DNA reproducing very quickly
Causing serious damage

20
Q

Continued active stage

A

Active TB is usually the result of the deactivation of old or controlled infectious rather than the new one

Bacteria reproduce rapidly causing rather noticeable symptoms such as
Night sweat
Loss of appetite
Weight loss

The patient will start coughing out liquid produced in the lungs called septum

If the infectious become serious the lungs is heavily damaged the patient will start coughing blood.

Alveoli start to breakdown and produce large inefficient air sacs
—> bacteria also attacks T cells to stop production of antibodies and although the body raise its temperature to kill the bacteria the bacteria can survive up until 42c

Metabolic enzyme start to denature at 40c eventually the patient dies due to organ failure no respiration or due to invasion by opportunistic disease

21
Q

Treatment and control of antibiotics

A

These antibiotics kill rapidly reproducing bacteria as well as hidden bacteria in the tissue

22
Q

Improving living standards

A

People living in crowded areas as well as malnourished or unhealthy immune system are most vulnerable to TB preventing these conditions can prevent disease

23
Q

Immunisation

A
24
Q

How does deterioration social condition increase TB

A

Increasing migration of refugees and foreign travel as well as increasing drug use is all increasing the cases of TB

25
Q

How is HIV transmission

A

1) exchange of fluids

2) inoculation through blood

3: mother to fetus

26
Q

HIV life cycle step 1 BINDING

A

On the surface of a T cell HIV binds to a CD4 receptor

27
Q

HIV life cycle step 2 FUSION

A

The virus fuse with the host cell membrane and release genetic material (RNA) into the cell

28
Q

HIV life cycle step 3 REVERSE TRANSCRIPTION

A

The single stranded HIV RNA is converted into double stranded HIV DNA by reverse transcriptase enzyme

29
Q

HIV life cycle step 4 intergation

A

After the HIV DNA enter the cells nucleus, the enzyme integrase cuts the cell DNA and insert cells DNA into it

30
Q

HIV life cycle step 5 TRANSCRIPTION AND TRANSLATION

A

The enzyme RNA polymerase makes RNA copies of DNA. HIV RNA is either inserted into new virus particles or processed and translated into HIV protein

31
Q

HIV life cycle step 6 ASSEMBLY

A

The long protein chain cuts into the individual protein by the enzyme HIV protease a new virus is assembled with these protein and HIV RNA

32
Q

HIV life cycle step 7 RELEASE

A

The new virus particles is released from the host cell, taking with it part of the cell membrane and capable of infecting other cell

33
Q

STAGE 1 ACUTE HIV syndrome

A

May not experience any symptoms at first.

Afterwards May feel unwell
- fever
-tiredness
-swollen glands

34
Q

Stage 2 CHRONIC STAGE

A

after infection symptoms may disappear

Often this period the person may not show symptoms for years due to
- well-nourished
- anti- retrovirus drug

35
Q

Stage 3 SYMPTAMATIC DISEASE

A

Gradually the virus reduces the number of helper T cells
-B cells no longer activated
-no antibodies are produced

Patient suffers
-weight loss
Fatigue
Diarrhea
Night sweat

36
Q

Stage 4 advanced AIDS

A

Lack of T helper cells decreases the body ability to fight off infection
Leading to AIDS
Symptoms
-dementia

37
Q

Factor affecting how quickly HIV progress to AIDS

A

The number of existing infection

The strain of HIV the person is infected with

Their age

Access to healthcare

38
Q

Ways to prevent HIV

A

1) celibacy and having one sexual partner
2) using condoms during sexual activity to prevent virus transfer
3)using clean needles if injecting drugs

39
Q

Vaccines preventing HIV

A

HIV is able to mutate quickly so by the time the vaccine goes through the virus would’ve adapted against

Natural selection favours mutated viruses

40
Q

Drug therapy HIV

A

Helped pro long life expectancy as they are anti-retrovirus will help keep the immune system strong to fight off the AIDS

Biology U4 (9 decks)

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