The immune system Flashcards

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1
Q

what is the immune system

A

the body’s defences system use to protect the organism from pathogens

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2
Q

what are the three lines of defence

A

the first line of defences
- barriers that prevent entry of the pathogens
second line of defences
- non-specific responses to a pathogens
the third line of defences
- the adaptive/ specific immune response

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3
Q

for the first layer of defence what are the difference physical barriers

A
  • skin
    -coughing and sneezing reflexes
    -mechanical protection
    -mucus
    -stomach acid
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4
Q

explain the skin as a physical barrier

A

-physical barrier
-is made up of tissues and is the largest organ of the human body
- the upper layer, epidermis consists of dead cells containing keratin forming a protective layer
-lipid molecules are secreted from glands which provide a waterproofing agent to prevent access to microbes

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5
Q

what happens if the skin is breached

A

cells called platelets initiate clotting factors that seal the point of entry for pathogens

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6
Q

explain the coughing and sneezing reflexes as a physical barrier

A
  • physical barrier
  • although it is a method of transmission, this involuntary action helps expels the pathogens
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7
Q

explain mechanical protection as a physical barrier

A
  • blinking is initiated as a response to irritation in the eyes
    -tears particles and pathogens are mixed so they can be eliminated from the eye
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8
Q

explain mucus as a physical barrier

A
  • physical barrier
  • is a slippery secretion found on the surface of several body organs and systems
    -produced by specialised epithelial cells that line the organs eg:bronchi of the respiratory system
  • on the surface of these cells are small hair like structures called cilia that have a rhythmic motion which directs mucus and foreign particles in the respiratory organs to the pharynx and mouth to be swallowed or expelled
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9
Q

on the surface of the mucus cells there are…

A
  • on the surface of these cells are small hair like structures called cilia that have a rhythmic motion which directs mucus and foreign particles in the respiratory organs to the pharynx and mouth to be swallowed or expelled
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10
Q

explain stomach acid as a physical barrier

A
  • physical barrier
  • the cells lining the stomach secrete acid (HCI) giving the stomach a low pH
  • this is considered an extreme environment and if a pathogen gets this far into the system, either by swallowing them or carried by mucus the acid will destroy them
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11
Q

what is immunity

A

the term immunity refers to the ability of a host to resist infectious disease

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12
Q

what happens if any microorganisms that can penetrate the physical barriers encounters two levels of resistance

A

non-specific (innate)
- second line of defence
specific (acquired)
- third line of defence

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13
Q

example of non-specific

A

cells
physical barriers

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14
Q

examples of specific

A

cells
chemical mediators

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15
Q

the second line of defence is characterised by being..

A
  • non-specific
  • a rapid non learned response
  • responds in a similar matter
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16
Q

what does the second line of defences involve

A
  • phagocytes and phagocytosis
    -non-self recognition
    -white blood cells and killer cells
    -chemicals Eg: histamine
  • inflammatory response
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17
Q

what is phagocytosis

A

process that certain white blood cells use to ingest pathogens

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18
Q

what are natural killer (NK) cells

A

provide protection against cells infected with a pathogen

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19
Q

Natural killer cells carry out their actions by…

A
  • recognising protein marked ‘non-self’ on cells that need to be destroyed
    -releases cytokines which are cell-signalling molecules that guide other responses
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20
Q

what is the complement system

A

it is a group of about 30 proteins that are secreted by cells in the body. They are active when binded with pathogens and bring around a cascade affect, stimulating a range of chemicals and effects

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21
Q

how is the inflammatory response characterised

A
  • swelling
  • redness
  • pain
  • heat that accompanies a wound from psychical injury and pathogen of wound site
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22
Q

what is histomines

A

histomines increases blood flow to increase permeability of capillaries in the inflammatory response

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23
Q

histomines increases blood flow to increase permeability of capillaries in the inflammatory response- what does this cause?

A

this causes mast cells to release histamine which causes blood vessels to dilate at the site of infection, bringing extra blood to the region. this carries while blood cells to engulf the microbes

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24
Q

what does blood clotting do in the inflammatory response

A

blood clotting factors are also released and seals the wound leaving a scab

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25
Q

what can form around the wound

A

pus can form around and in the wounds by the action of white blood cells called neutrophils

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26
Q

what are neutrophils

A

white blood cells

27
Q

what is the lymphatic system

A

primary- where lymphocytes develops such as bone marrow and thymus glands
secondary- lymph nodes, spleen and tonsils, this is where white blood cells recognises pathogens and mount responses

28
Q

what does bone marrow create

A

WBC -white blood cells

29
Q

what does thymus allow

A

WBC to mature

30
Q

what does the lymph nodes and the spleen do

A

filter pathogens through and exposes WBC

31
Q

what are antigens

A

a substance that triggers specific defences in the immune system( protein fount on pathogens cell surface)

32
Q

what are antibodies

A

a substance that is produced within an organism’s body to help fight and recognise pathogens

33
Q

what is lymphocytes

A
  • white blood cells of the immune system are called lymphocytes. these are found in spleen and blood
    -there are two tyeps b cells and t cells
34
Q

what are the two lymphocytes

A

B-cells and T-cells

35
Q

what are B-cells

A

B-lymphocytes
-produced and matured bone marrow, responsible for producing antibodies
- vital for the development of immunity

36
Q

what are T-cells

A

T-lymphocytes
- produced in bone marrow and mature in thymus
-stays in lymph nodes for filtration
-removes pathogens in the body
- T-cells trigger B-cells to develop killer cells

37
Q

what are produced by T-cells and B-cells

A

helper cells or killer cells

38
Q

major histocompatibility complex (MHC) are…

A

-a set of protein makers found on the surface of the cell.
- these are coded by genes unique for all individuals

39
Q

what does MHC stand for

A

major histocompatibility complex

40
Q

cells display two different groups of MHC on the cell surface these are

A
  • self proteins- that are unique for that individual
    -short section of PROTEIN ANTIGENS from pathogens, these groups play vital role in the adaptive immune response, these are NON SELF
41
Q

the display antige enables…

A

Recognition and binding by T-lymphocytes which acts as a further immune response

42
Q

if a pathogen comes along

A

it breaks past the first line of defence and it is able to bypass the second line of defences but once in enters the blood stream the 3rd immune response comes into play

43
Q

if the body recognizes the antigen…

A
  • antibodies already in the blood stream (memory B cells)
  • antibodies ‘tag’ and disable the pathogen
    -T-cells notify killer cells to destroy the pathogen
44
Q

if the body doesn’t recognises the antigen…

A

-B-cells and T-cells are present in the blood stream
- B-cells with identify non-self antigen on the pathogen
- this will active killer T-cells
- Provide memory T-cells for subsequent exposure to the same antigen
-activate specific B-cells to secrete antibodies

45
Q

what are killer T-cells

A

they are know as cytotoxic T-cells, they identify infected cells and secrete chemicals to destroy them

46
Q

what are memory T-cells

A

if an individual is exposed to the same antigen a second time, the memory cells detect this and begin a response quicker

the memory T-cells contributes to the secondary immune system

47
Q

what is passive immunity

A

-protection against a protent antigen where immediate action is needed to prevent death Eg; snake bite

48
Q

why is passive immunity important

A

this can be important in several circumstances
- proving protection for unborn and newborn infants who have yet to fully develop their immune system. antibodies can be transferred from the mother via placenta tor breast milk

49
Q

what is the two different acquired immunity

A

primary and secondary

50
Q

what is the primary response for acquired immunity

A

the primary response is smaller and slower due to the action of the first two lines of defence and the stimulation of the B-cells and production of the antibodies while the secondary response is faster and larger due to the memory cells being created

51
Q

what is the secondary response for acquired immunity

A
  • is the basic of vaccinations
    -an individual is exposed to a part or a dead part of the virus
  • the body raises an unneeded immune response and the different memory cells are created
  • this lessens the time needed for the immune response if they were to be infected by the real virus
52
Q

what is pathogenicity

A

-is the ability if a pathogen to cause infectious disease
- this is ability of a pathogen to be transmitted from one host or source to another- transmission

53
Q

how can transmission occur

A
  • airborne
  • vector-borne
  • contact
  • contaminated food and water
  • body fluids
54
Q

transmission via airborne is becuase

A

-air is not suitable medium foe the growth of pathogens but it can carry them between organisms
-airbron disease is often caused by sneezing or coughing

55
Q

example of airborne disease

A

influenza
- airborne pathogens are contained in fluids and droplets in the respiratory tract
-can infect another host why inhaled

56
Q

transmission via vector borne…

A
  • they carry the pathogen but do not suffer the disease
    -are commonly arthropods (ticks and mites) and vertebrate (rats and bats)
57
Q

what are vectors

A

vectors are living transmitters of pathogens

58
Q

when does external transmission of vector borne diseases occur

A

it occurs when the pathogen is on the surface of the body

59
Q

when does internal transmission of vector borne diseases occur

A

it occurs when the pathogens is carried inside the vector

60
Q

transmission via contact…

A
  • it occurs when the pathogen is transmitted to the host by direct or indirect contact
61
Q

what is direct contact

A

it refers to the pathogen being transmitted from person to person touching, kissing and sexual contact

62
Q

what is indirect contact

A

refers to the pathogen being transmitted from the sources to the host through non-living objects called vehicles

63
Q

transmission via food and water

A

-Certain communities struggle to keep their water ways clear, therefor are prone to disease. laws are requited in order to keep our food preparation safe for consumption
-microorganisms feed on the same nutrients as humans

64
Q

what water can cause serious disease if consumed

A

water that has been contaminated by fecal matter either by humans or animals and contain pathogens