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Biology > Immunity Topic 7 1st year > Flashcards

Immunity Topic 7 1st year Flashcards

1
Q

What are microbes/pathogens?

A

Disease causing organisms which can live on or inside our body

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2
Q

Name some examples of microbes

A

Bacteria
Viruses
Fungi

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3
Q

Name some diseases which these microbes cause

A

Bacteria : meningitis or tubercolosis
viruses: hepatitis or small pox
fungi: athlete’s foot

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4
Q

Mention a type of beneficial bacteria and where it can be found

A

Symbiotic bacteria which is found in the large intestine of humans which produces vitamin K and B12

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5
Q

What are the 3 main body barriers which prevent these harmful microbes from invading the body?

A

3 lines of defence

Primary barriers: These are physical barriers which keep microbes out of the body

Non-specific internal defences: attack “all microbes no matter what it is” and a general response is produced by the body

Specific internal defences: combats specific microbes

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6
Q

Give examples of structures which form part of the 1st line of defence

A

Skin
mucous membranes
secretions
cilia

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7
Q

Why is the skin an excellent habitat for these microbes to live on the skin?

A

Because the skin is warm ,moist and has a good source of nutrients for these microbes

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8
Q

How is the skin adapted to prevent the entry of pathogens?

A

The skin is hardened,slightly acidic and salty and is impermeable to water due to a substance called sebum secreted by the epidermal cells

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9
Q

True or false.

There is beneficial bacteria on the skin.

A

True.

These beneficial bacteria can even eliminate much more harmful bacteria which are on the skin

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10
Q

True or false

Not every single part of the body has dead keratin impregnated cells which prevent the entry of microbes, because there are several opening present. Therefore the body produces secretions to try and prevent these pathogens from entering the body

A

True

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11
Q

Give some examples of how the body further protects the body from invading it which forms part of the first line of defence.

A

1) In the mouth there is the secretion of the lysozyme enzyme to kill any potential bacteria. If the bacteria manage to survive the lysozyme attack the stomach produces hydrochloric acid for additional bacterial breakdown.

2)In the ears there is the secretion of wax.

3) In the nasal cavity globlet cells produce mucous, and the presence of cilia help to beat the mucous containg pathogens in it where they will be sneezed .

4) Eyes contain lysozymes that digest bacteria,keeps the eyes sterile.

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12
Q

If there are any cuts present in the skin, how does the body heal it to ensure that no pathogens can enter it?

A

Cuts are any unnatural gaps found in the skin. The skin cells will close these gaps with the help of plasma proteins and platelets. The skin cells will also regenerate to dry and heal the wound. The seal will prevent the entry of pathogens

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13
Q

What will happen if the first line of defence is not enough in order to prevent microbes from entering the body?

A

The second line of defence comes into play

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14
Q

How is the second line of defence divided?

A

Non-specific immune response

Specific immune response

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15
Q

Describe the specific immune response

A

The immune response is specific and relies on prior experiences and encounters with the microbe. specific substances are released to kill the microbes

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16
Q

Describe the non-specific immune response

A

Consists if an inflammatory reaction against the disease. It also includes white blood cells that digest the microbes

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17
Q

What biological term do we use to describe non-specific immune responses?

A

Passive immunity

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18
Q

What biological term do we use to describe specific immune responses which form part of the 2nd line of defence?

A

Acquired Immunity

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19
Q

A new-born is born. However initially the immune system of the baby is not yet in full fight mode. Why?

A

Because the baby received some antbodies from its mother (passive immunity). But then as the baby continues to grow,the immune system of the baby can distinguish between self and non self. This is called active immunity.

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20
Q

How can we further divide the types of “attacks” regarding the non-specific immune responses?

A

Inflammation
Fever
Phagocytes
Natural killer cells

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21
Q

What is inflammation?

A

A local response to tissue damage

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22
Q

What causes an inflammation?

A

It could be caused by microbial invasion, irritants containing harmful chemicals, cuts and other types of physical damage to the tissues.

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23
Q

What chemicals and type of hormone does the damaged tissue release when there is an inflammation?

A

Chemicals: prostaglandins and
the hormone histamine.

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24
Q

What is the function of histamine and prostaglandins during an inflammation?

A

They will cause the arterioles to vasodilate to increase the blood flow towards the damaged area. And the permeability of capillaries also increases

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25
What will happen to the capillaries due to the increased permeability?
Larger amount of blood flow, this will also cause swelling, redness and the temperature to rise. This can lead to pain in the damaged area.
26
What is the purpose of the permeability in the capillaries?
This will allow white blood cells like macrophages and other phagocytic cells to squeeze through the pores to fight the pathogens. Phagocytes will engulft the bacteria and digest them.
27
What is pus?
The material which ooes out of a healing wound,which consists of dead white blood cells,microbes and tissue debris,they are both living and dead.
28
How do the white blood cells know that there is a damaged area in the body ?
Because the damaged area and the microbes themselves will release chemicals which are going to attract the macrophages to get to the injured site.
29
Which types of white blood cells are responsible to carry out phagocytosis?
Phagocytes Neutrophils and macrophages
30
What are neutrophils?
Neutrophils are types of phagocytes and they are the first types of white blood cells to arrive on site. They are able to squeeze through capillary walls and tissue spaces.
31
What are macrophages?
White blood cells that patrol in tissues and can be found in the liver,spleen or lymph nodes.
32
From which cells do macrophages develop from?
Monocytes
33
What will the macrophages do when after they have digested the bacteria?
Some breakdown products are presented on the memebrane of the macrophage itself,to stimulate the action of lymphocytes.
34
Describe more in detail the characteristics of phagocytes
Phagocytes they engulf bacteria and remove debris or dust in the body for example the lungs. They show ameboid movement (move by their cytoplasm) (ameboid structure and function) They are able to recognize invading microbes and can detect where tissue damage has occurred.
35
After some phagocytes broke down the bacteria,what will some phagocytes do with the ingested material?
The phagocytes which have broken down the bacterium, will present the ingested material on the surface of the cell as antigens in order for them to be recognized by other white blood cells called lymphocytes (specific immune response)
36
Name the structures in a white blood cell
lysosome nucleus cytoplasm cell membrane (for the phagocytosis diagram)
37
Very briefly explain what happens in phagocytosis with a food particle
The organism will ingest the food particle The food particle will form into a food vacuole Then the lysosome will digest the food vacuole
38
What are natural killer cells?
They are another type of white blood cell. However they are a type of lymphocyte which look a lot like T and B cells but they are NON-SPECIFIC in their action
39
What do natural killer cells mainly target?
They are cells which target cancer and viral cells Natural killer cells secrete chemicals on the membranes of infected cells
40
True or false Natural killer cells conduct phagocytosis
FALSE They secrete chemicals onto the membranes of infected cells. They will secrete enzymes onto the memebranes of incfected cells,this will cause the membranes to become leaky and it will kill the bacterium
41
How do natural killer cells aid in the communication of lymphocytes?
Because after the natural killer cells have killed a bacterium, they will release chemicals called cytokines which are going to stimulate the action of the T- cells and B-cells.
42
Where are natural killer cells made in the body and where do they mature ?
Made in the bone marrow and mature in the absence of the thymus
43
When is a fever caused by the body?
When there are a lot of microbes in the body which will cause the white blood cells to increase in number.
44
What hormone is released by white blood cells which is going to change the body temperature?
Pyrogen Pyrogen will stimulate the hypothalamus and will change the body temperature.
45
Why is the body temperature raised during a fever?
This increase in temperature will disrupt the reproductive ability of bacteria,which allows the white blood cells more time to kill the bacteria
46
Name some symptoms of a fever
Shivering Decrease in iron concentration in the blood because bacteria need iron to reproduce which will make u feel tired and weak
47
What type of white blood cells do the specific immune response have?
Lymphocytes
48
What are the 2 types of lymphocytes?
B-cell and T-cells
49
Where are T-cells and B-cells formed and where do they differentiate?
T-cells are made in the bone marrow and mature in the thymus gland B-cells are made in the bone marrow and differentiate in the bone marrow
50
Name the 3 sequences of B and T cells
Recognition Launching Retaining
51
Define recognition
Recognition of the invading microbe due to the presence of antigens on the plasma membrane
52
Define Retaining
Retaining the memory of the foreign invader for the prevention of future infections
52
Define launching
Launching a successful attack with killer cells and antibodies
53
What causes antibodies to be produced in the 3rd line of defence?
Antigens which are found on the microbe
54
Therefore what do antigens produce?
Antibodies
55
Therefore what are antigens exactly?
Antigens are cell identity markers or infectious agents. which are going to fit into the binding site of antibodies, which will trigger a specific immune response.
56
What are antigens made up of?
Proteins or carbohydrates
57
Where can antigens be found ?
They can be attached to the surface of cells or on microbes. They can be even found in blood plasma
58
True or false Antigens can genetically modify themselves
True Antigens are able to change all the time on a virus. This is because a virus undergoes mutations all the time. Therefore, these mutations can actually help the micro-organism survive the attacks of the immune system. When antigens of a particular microbe chnage,they can still re-infect the same organism as if there were no antibodies present to fight the microbe.
59
What are antibodies?
Y shaped proteins which are produced by B-cells, which bind to antigens, they can either neutralize the antigen molecule OR they can mark the cells which carry that specific antigen so that these microbes can be destroyed.
60
What are antibodies made up of?
Plasma protein (globulin)
61
What can we also call antibodies?
Immunoglobulins
62
Where are antibodies produced?
In lymphoid tissues
63
What are the 2 types of antibodies?
Soluble antibodies which are secreted from B -cells or membrane bound antibodies which are attached to B-cells
64
Describe the structure of antibodies
They are made up of 4 polypeptide chains 2 heavy chains(long) 2 light chains (short) Made up of 2 regions called the constant and the variable region The variable region is the highly specific one because this is the binding site. Made up of different sequences of amino acids The constant region: is made up of constant sequences of amino acids
65
What are the 2 main functions of antibodies?
Receptors and effectors
66
Why can antibodies act as receptors?
Since the antibody is made up of 2 binding sites, the antibody can stick to more than 1 microbe holding a clump of microbes together. This is called agglutination
67
Why can antibodies act as effectors?
The binding of a fixed antibody on a specific antigen,will trigger other B-lymphocytes to produce that specific antibody and release it in the bloodstream. (positive feedback). These antibodies can nautealize other antigens,destroy microbes containing antigens and promote phagocytosis by macrophages.
68
True or false B-cells also release antitoxins which neutralize bacterial toxins
True
69
True or false Agglutination does not enhance the action of phagocytes
False It does enhance phagocytosis,because agglutination causes several bacterial to clump to each other and this will make it easier for more phagocytes to recognize the invading microbes and it also weakens the bacteria.
70
Mention the 2 types of attacks which the 3rd line of defence makes use of
Humoral by B cells (provided by antibodies in the plasma) Cell-mediated by T-cells(T-cells are going to destroy infected body cells)
71
Describe what happens in humoral immunity
This involves B-cells. B-cells will conduct a specific immune response because they are able to recognize microbes by their antigens. Therefore, the B-cell will recognize that their is a pathogen in the body and will start to produce antibodies. Antibodies are Y shaped proteins with a specific antigen binding site which will bind to the antigens on the pathogen. Then the antibodies will mark the pathogen as a target for destruction When the antibody actually binds to the antigen, the B-cell gets stimulated to start to make copies of itself. These clones are called plasma cells which are going to continue to make antibodies for that specific type of antigen AND then they get released into the bloodstream
72
True or false Millions of antibodies are produced by B-cells
True
73
True or false When a pathogen enters the body, an antibody will bind to the antigen that is complimentary to that specific antigen
True When the pathgoen has not encountered a lymphocyte which is not complimentary,it will surely find a B-cell which is complimentary to its antigen ,since millions of antibodies are produced in the body
74
Why do we call humoral immunity "humoral"?
Because this type of specific immune response is conducted only against invaders which have not YET actually entered into the body cells
75
Mention a structural characteristic of plasma B cells?
They have very high amounts of rough endoplasmic reticulum.,therfore they will secrete huge ammonts of antibodies per second.
76
What are memory B cells?
They are other types of cells where the antibody genetic new code is going to get stored in ,these cells will usually last for years in order to prevent a future infection. Whenever that specific microbe is encountered agin,the memory B cells will chnage into plasma cells and will continue to start producing antibodies for that specific antigen. These memory B cells have a longer lifepan
77
What types of cells form part of cell-mediated immunity?
T-cells
78
When is cell-mediated immunity initiated?
When pathogens in the body have entered a cell and have infected it such as viruses
79
What do T-cells usually destroy?
Cancer cells or viruses which have entered cells
80
How many T-cells are usually involved in cell-mediated immunity?
3 Killer T-cells Helper T-cells Suppressor T-cells
81
Describe how cell-mediated immunity is conducted
A pathogen will present antigens which are found on the cell surface membrane to be recognized by T-cells and macrophages
82
What is the role of killer t -cells
They will destroy the pathogen by punching the membrane
83
What is the role of helper t-cells
Activate killer-t cells and stimulate B-cells to produce antibodies
84
What is the role of suppressor T-cells?
To stop an immune response (stopping the action of B-cells and T-cells)
85
What are memory T-cells?
Memory cells which store information like the memory B-cells. Memory t-cells can produce large ammount of killer t-cells and plasma cells.
86
Is the immune response slower or faster if you get sick the second time with the same pathogen?
Fatser because the memory cells repond much more quicker,during the first time that you get sick the B-cells and T-cells respond much slower.
87
Therefore what exactly is a memory cell?
Memory cells are produced in the 3rd line of defence after the immune response by the B-cells and T-cells has been done. Memory cells have a longer lifespan and would remember any pathogens that would have caused the same disease However a person can still catch the common cold because the virus/pathogen is all the time chnaging its structure and antigen and then the memory cells will not recognise it.
88
Give an example where T-cells and B-cells are working together
Helper T-cells will stimulate the action of B-cells to start to produce antibodies. Then the B-cells will start to make copies of themselves called plasma cells
89
Mention 2 methods how passive immunity can be acquired
Antibiotics and vaccinations
90
Define vaccination
Vaccination is the introduction (usually through an injection) of weakened or killed microbes into the system to cause immunity, as the body reacts to the antigen as if it were potentially harmful.
91
How do vaccinations help to acquire passive immunity?
Because antibodies will be formed in response to the antigens introduced in the body. Then it will be stored as memory cells. When the real microbe is encountered the body will have the specific gene in order to fight it.
92
What are the 2 ways that vaccinations can be introduced in the body?
The introduction of a weakeaned organism. The organism will not be able to reproduce but the antigens will still be present and the body can react to that antigen The introduction of the gene coding for the antigen into the genetic material of a harmless organism.The organism will produce the antigen into the body. The the body will react to the antigen.
93
What are allergies?
A form of immune response to substances that are not harmful like pollen, dust or bee stings. People who do not have allergies usually do not have the gene for allergies or produce less of the antibody.
94
Describe what is HIV.
The virus will not kill the host directly,its other organisms that will kill the host Since the cir us does not attack the host directly its very difficult to diagnose because the disease is mainly identified through severe secondary infections that would otherwise be harmless AIDS is caused by a depression in the immune response due to the HIV preventing helper t-cells from activating B-cells and will also cause T-cells to burst due to many viruses being released. Also when T-cells become activated to gith another virsu HIV also increases This causes a decrease in the strength of the immune system because the person develops several infections and disease like skin lesions and pneumonia, or when maternal and foetal blood components get mixed together during pregnancy or childbirth.
95
What is an antibiotic?
Some microbes they can reproduce so rapidly or secrete toxic products they do not allow the immune system to respond. Therefore,antiobiotics will slow down the growth and multiplication of many microbes, which will allow the immune system enough time to finish and do its job Antibiotics only have an effect on bacteria and they are useless against viruses Antibiotics slow down microbial growth and reproduction of bacteria
96
Define an antibiotic
A substance which is produced by a micro-organism and that can kill or inhibit the growth of micro-organisms even in small concentrations
97
True or false Bacteria can be resistant to antibiotics sometimes
True because bacteria are constantly mutating and therfore they can become resistant to bacteria Therefore, through natural selection the bacteria can also continue producing antibiotic resistant bacteria
98
Draw a diagram of a B-cell with antibodies and a bacterium showing its antigens
99
Draw a diagram of an antibody

Biology (19 decks)

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