4.1.1 Communicable Diseases Flashcards

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1
Q

what is a communicable disease?

A

a disease caused by a pathogen that can be passed form one organism to another

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2
Q

what is a pathogen?

A

a disease causing microorganism

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3
Q

what is a vector? common vectors?

A

an organism that carries pathogens form one organism to another
- water and insects

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4
Q

name the types of pathogens?

A

bacteria, viruses, fungi, protoctista

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5
Q

what do bacteria not have?

A

no membrane bound organelles / nucleus

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6
Q

ways in which bacteria are classified?

A
  • basic shapes

- basic structure of cell wall

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7
Q

basic shapes of bacteria?

A
  • rod shaped (bacilli): food poisoning
  • spherical (cocci): acne
  • comma shaped (vibrios): cholera
  • spiralled (spiralli): stomach ulcers
  • corkscrew (spirochaetae)
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8
Q

how to bacteria replictae?

A

binary fission

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9
Q

why do bacteria replicate using binary fission? problems with this?

A
  • faster, exponential growth
  • allows large colonies to be made
    + can cause food spoilage
    + rapid spread of disease
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10
Q

function of capsule in bacterial cells?

A
  • protects cell from indigestion by phagocytosis
  • helps them cling together and to various surfaces
  • prevents drying out
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11
Q

types of cell wall in bacteria? what does the cell wall determine?

A
  • gram positive: purple under a light microscope
    MRSA
  • gram negative: red under a light microscope
    E. Coli
  • how the bacteria responds to antibiotics
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12
Q

what is a virus?
diameter?
how much smaller than a bacterium?
basic structure of a virus?

A
  • non-living infectious agent
  • 0.02μm
  • 50 x
  • some genetic material surrounded by proteins
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13
Q

what is a bacteriophage?
what does it do?
what are they used for today?

A
  • a virus that kills bacteria
  • take over bacteria and use them to replicate and destroy bacteria
  • used to identify and treat some diseases
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14
Q

how do bacteria cause disease?

A
  • produce toxins

- the symptoms they cause are due to the damage to the call membrane/enzymes/genetic material

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15
Q

basic structure of a bacteriophage?

A
  • looks like a spider lol
  • long tube: injection tube
  • tail plate attached below the injection tube
  • head contains loose genetic material and protein coat
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16
Q

describe how viruses invade living cells?

A

-

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17
Q

what is the body’s first line of defence?

A

skin, clots seal wound

18
Q

what is a non-specific defence?

A

targets any type of pathogen

19
Q

non-specific defence: mucus?

A

contains lysosomes which destroy the cell wall of pathogens

20
Q

non-specific defence: what parts of the body contain mucus? lysosomes?

A

mucus: air tracts, nose
lysosomes: tears, sweat, saliva, urine

21
Q

non-specific defence: urine

- women?

A

lysosomes
allows physical washing of urinal tract
- in women, menstruation and discharge allows washing of the urinary tract

22
Q

non-specific defence: expulsive reflexes

A

coughing, sneezing: expel mucus

vomiting/diarrhoea: expel contents of the gut

23
Q

non-specific defence: what is thrush?

A

caused by pH change in vagina

24
Q

non-specific defence: ear

A

contains wax which works like mucus

25
Q

non-specific defence: eye

A

rapid eye movement moves pathogens to front of eye to be washed away by tears
- micrboes die in the salty conditions of tears

26
Q

non-specific defence: gut

A

good gut bacteria (probacteria) and in breast milk

- compete with bad bacteria

27
Q

non-specific defence: skin

A

sebaceous glands secrete an oily substance called sebum which inhibits the production of pathogens

28
Q

non-specific defence: birth reflex?

A

when the baby is pushed down, it pushes against the birth canal which causes the uterus to push the baby down

29
Q

non-specific defence: anus

A

defacating expels pathogens in diet

- ring of muscle in anus is a good physical barrier for pathogens

30
Q

explain dead skin cells?

A

outer layer of skin called epidermis
contains layers of cells
these cells are called keratinocytes
produced by mitosis at the base of the epidermis
migrate to surface of skin
as they migrate, they dry out
the sytoplasm is replaced by the protein keratin
called KERATINISATION
takes 30 days
by time cells reach surface, no longer alive
- this keratinised layer of dead cells acts as an effective barrier for pathogens

31
Q

describe what happens during blood clot formation (not cycle)

A

skin is breached, pathogens enter
platelets come into contact with collagen in the blood vessel, they ADHERE and secrete various substances
- thromboplastin
- seratonin
clot dries
epidermal stem cells mitose and migrate to top of epidermis and differentiate forming new cells
- scab sloughs off, wound healed :D

32
Q

what is the function of thromboplastin in the blood clot response?

A
  • enzyme that initiates a cascade of events that lead to a blood clot
    (memorise the cycle)
33
Q

what is the function of serotonin in the blood clot response?

A
  • causes the smooth muscle to contract, restricting blood vessel and reducing blood flow to area
34
Q

describe the inflammatory response?

A

presence of microorganisms detected by specialised cells called MAST CELLS
release a cell-signalling substance called HISTAMINE and CYTOKINES
(more)

35
Q

what do histamines do in the inflammatory response?

A
  • make blood vessels dilate, causing localised heat and swelling: raised temp prevents pathogens form REPRODUCING
  • make blood vessels more leaky, forcing blood plasma out of capillaries, called tissue fluid CAUSES SWELLING AND OEDEMA
  • drain into lymphatic system
36
Q

what do cytokines do in the inflammatory response? fever?

A

attract phagocytes to site

- stimulate hypothalumus to reset the thermostat and temp goes up

37
Q

why is a high temp useful for killing pathogens?

A
  • high temp pathogens dotn reproduce well

- specific immune system works faster

38
Q

types of phagocytes?

A
  • neutrophils: multi-lobed nucleus, manufactored in bone marrow10 mins to engulf, get through pores in capillaries
  • macrophage:
39
Q

describe phagocytosis in neutrophils

A

1) phagocyte binds to the opsonin attached to the antigen of the pathogen
2) the cell membrane of the phagocyte fuses around the bacterium, enclosing it in a vacuole by endocytosis- phagosome
3) a lysosome fuses with the vacuole: phagolysosome and empties its digestive enzymes to digest it
4) antigens are presented on the surface, useful products are taken into the cytoplasm by diffusion / AT

40
Q

describe phagocytosis in macrophages

A

-