Disease and immune system Flashcards

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1
Q

What is a pathogen?

A
  • Is an organism that causes disease
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2
Q

What are the types of pathogens ?

A
  • Bacteria
  • Virus
  • Fungus
  • Protocist
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3
Q

Explain Bacteria

A
  • Prokaryote
  • produce toxins - chemicals that interfere with enzyme reaction causes lack of certain proteins
  • Tubercolosis - example of animal bacteria causes respiratory issues (lung tissue)
  • Ringrot - plant damage in tomatoes, fruit potatoes and tomato , targets leaf so photosynthesis is unable to take place
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4
Q

Explain fungi

A
  • spread by making spores
  • can also produce toxins
  • saprophytic organisms so can digest and feed on dead organisms
  • animal disease : Athletes foot
  • plant disease - black sigatoka - destroys the leaves causing black lines on the leaves
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5
Q

Explain Virus

A
  • Hijack cells to reproduce
  • Inject genetic material into host cell
  • Genetic material combines with host cell DNA
  • Viral DNA/RNA and proteins are made using the host cells’ resources and mechanisms
  • animal disease - AIDS - target t-helper cells
    -plant disease - Tobbaco mosaic virus - discolouration (losing chlorophyll) saic pattern on leaves
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6
Q

Explain Protist

A
  • animal disease, malaria through vector (mosquitoes)
    transferred from the mosquito into the bloodstream reproduces into cells
  • plant disease - potato blight -
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7
Q

What is direct transmission ?

A

Disease directly transmitted from one organism to another e.g droplet infection , sexual intercourse or touching an infected organism
- Inoculation - blood transfusion, sharing needles, Ingestion (contamination through food)

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8
Q

What is indirect transmission ?

A
  • transmitted via an intermediate (air, water food, organism or another organism (vector)
  • Fomites: using or touching contaminated things
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9
Q

How does transmission happen in plants ?

A
  • Direct contact
  • Vectors
  • Contamination of soil
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10
Q

What are the factors that affect transmission ?

A
  • Hygiene
  • Weak immunity
    Overcrowding: easy for pathogen to be transmitted
    Genetic variation; natural susceptibility
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11
Q

WEBISM

What are the main non-specific defences?

A
  • Skin
  • Mucous membranes
  • Blood clotting
    -Inflammation
  • Wound repair
    Expulsive reflexes
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12
Q

How does the skin protect against pathogens ?

A

Acts as a barrier , also as a chemical barrier, by producing antimicrobial and can lower PH inhibiting growth of pathogens.

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13
Q

How do mucous membranes protect against pathogens ?

A
  • Secrete mucus, a sticky substance that traps pathogens and contains antimicrobial substances
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14
Q

Explain blood clotting

A
  • A mesh of proteins that clots plug wounds to prevent pathogen entry and blood loss. They are formed by series of chemical reactions that take place when platlets are exposed by blood vessels.
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15
Q

Explain inflammation

A

-Inflammation is the body’s local response to infection and tissue damage, characterized by swelling, warmth, and pain around a wound.#
-Mast cells release histamine in response to tissue damage, leading to vasodilation and “leaky” capillaries, which allow fluid and plasma proteins to enter the tissues, causing swelling.

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16
Q

Explain wound repair

A
  • A scab is formed as a result of blood clotting
    Underneath this scab, there are stem cells that divide by mitosis to heal the wound
    Wound healing occurs in a number of overlapping stages:
    New blood vessels form
    Collagen is produced
    Granulation tissue forms to fill the wound
    Stem cells move over the new tissue and divide to produce epithelial cells
    Contractile cells cause wound contraction
    Unwanted cells die
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17
Q

What type of WBC identifies non-self cells ?

A
  • Lymphocytes
18
Q

How does lymphocyte identify non-self cell?

A
  • Its proteins (antigen)
19
Q

What is an antigen ?

A

An antigen is a protein in the cell surface membrane that triggers an immune response

20
Q

Explain phagoctyes

A
  • can bind to any antigen - non-specific response
  • complementary to molecular patterns on all pathogens
21
Q

What do lysosomes contain ?

A
  • lysozymes
22
Q

What are the 5 steps of phagocytosis ?

A

1) Phagocytes attracted to chemicals from the pathogen and moves towards it along a concentration gradient.
2) Receptor on phagocytes bind to molecular patterns on pathogens, recognising it as non-self cell
3) Phagocyte engulfs pathogen, forming a phagosome
4) Phagosomes fuse with lysosome forming a phagolysosome
5) Lysosomes release lysozymes which hydrolyse the pathogen.

23
Q

How do phagocytes manage to destroy invasive pathogens ?

A
  • They do so with the help of two chemicals - opsonins and cytokines
24
Q

What do cytokines do?

A
  • attract more phagocytes to site of infection so they can destroy as many pathogens as possible.
  • they are produced by phagocytes
25
Q

What do opsonins do ?

A
  • Bind to antigens on a pathogen and prevent pathogen from repelling phagocytes.
  • Phagocytes have receptors which are complementary to opsonin molecule
  • produced by our bodies
26
Q

What is the type of phagocyte with a lobed nucleus ?

A
  • Neutrophil
27
Q

Explain why it is important to stain blood smears with a differential stain.

A
  • -To distinguish between organelles
  • To provide contrast
  • To allow white blood cells to be seen and told apart from erythrocytes
28
Q

What are the types of lymphocytes ?

A

B lymphocytes - produced in bone marrow
- T lymphocytes - mature in thymus

29
Q

What does the B cell do ?

A
  • When a naive B cell’s receptors bind to an antigen on a pathogen, the B cell presents the antigen on its surface.
  • This processed antigen binds to receptors on a/an helper T cell.
  • When processed antigen binds to receptors on a helper T-cell, the helper T-cell then releases interleukins
  • These chemicals stimulate B cell to clone itself.
  • Then the clone differentiates into a plasma cell or a memory B cell.
30
Q

How long do plasma cells survive for ?

A
  • A few days
31
Q

How long do memory b cells last ?

A
  • For years, they wait in the body even after pathogen is destroyed and acts as a naive B cell .
32
Q

What do memory cells do ?

A
  • When a memory B cell encounters an antigen the the memory B cell’s receptors bind to an antigen on the pathogen.
33
Q

What are the differences between naive B cell and memory B cell ?

A
  • Memory B cell remembers so binds much faster, causing you to not get any symptoms
  • Second response causes you to make way more plasma cells
  • produces a greater concentration of antibodies than the first response
34
Q

What are the primary and secondary immune response ?

A
  • Firstly, we call the immune response that occurs the first time our body encounters an antigen the primary immune response.
  • The primary immune response involves naive B cells and forms the first lot of plasma cells and memory B cells.
  • Secondly, we call the immune response that occurs when our body re-encounters an antigen the secondary immune response.
  • The secondary immune response involves memory B cells and forms new plasma cells and more memory B cells.
  • It’s also quicker than the primary immune response and it leads to the production of a higher concentration of antibodies.
35
Q

What is the entire immune response known as ?

A
  • humoral response
36
Q

Identify why monoclonal antibodies detect the same antigen.

A
  • They all have the same tertiary structure.
37
Q

Describe how antibodies act as angglutinins.

A
  • Antibodies bind to complementary antigens on the surface of the pathogen, forming antibody-antigen complexes.
  • This causes pathogens to clump together in a process called agglutination, which makes it easier for phagocytes to engulf and destroy pathogens.
38
Q

What do antigen-presenting cells include ?

A
  • Phagocytes
  • B cells
  • Virus- infected body cells
39
Q

What are the function of helper T cell clones ?

A
  • can bind to antigen presented on B cell and this makes B cell clones
  • can release chemicals that stimulates phagocytes
  • Helper T cell can stimulate killer t cell - receptors bind to infected body cells and release perforins making holes and leads to cells death
  • Can develop into memory t cell
  • this is the cell mediated response
40
Q

Describe the different ways that the specific immune response leads to the destruction of antigens.

A
  • cell clones differentiate into plasma cells, which secrete antibodies. Antibodies bind to antigens on pathogens, causing them to agglutinate. This makes it easier for phagocytes to engulf and destroy foreign antigens.
  • Helper T cell clones stimulate phagocytes to destroy antigens by phagocytosis. They also stimulate killer T cells to secrete perforin, which kills infected cells and destroys the antigens within them.
41
Q

What are autoimmune diseases ?

A
  • Stop the immune system from recognizing self-cells
  • This triggers an abnormal immune response in the body that targets healthy tissue
42
Q

What are examples? of autoimmune disease ?

A
  • Lupus - causes rash on face and attacks internal organs
  • Arthritis - affects joints