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Biology > Chapter 8 - Immunity > Flashcards

Chapter 8 - Immunity Flashcards

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0
Q

What are pathogens?

A

Organisms that live on or in their host, and gain nutrients from that host.

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1
Q

What are infectious diseases caused by?

A

Pathogens

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2
Q

There are 2 types of pathogens. State them.

A

Ectoparasites: which attach themselves to the outside of the host. With the aid of specialised mouthparts, they penetrate the skin and feed on their hosts blood. Eg: bed bugs, ticks and fleas.

Endoparasites: live inside the host. Therefore they developed different ways of gaining nutrients from the host. In the human gut, blood vessels, muscles, lungs, etc. Very complex organisms & have adapted highly specialised features in order to life. Eg: tapeworm & viruses.

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3
Q

What can bacteria cause?

A

Meningitis, tuberculoid or diarrhoea

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4
Q

What can viruses cause?

A

Small pox, measles, influenza and hepatitis.

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5
Q

What can fungal cause?

A

Athletes foot.

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6
Q

What can protozoan cause?

A

Malaria and sleeping disease.

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7
Q

Many pathogens don’t harm us, due to barriers we have. What are these 2 barriers called?

A

Primary barriers: physical, chemical and cellular defences that prevent them from entering the body.

Secondary barriers: if they do enter, then there is a secondary line of defence. This type of defence is then divided into 2.

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8
Q

The secondary barrier, if further divided into 2. What are they?

A

Non Specific Immune Response: consisting of an inflammatory reaction against the disease. Phagocyctic white blood cells that digest microbes are released.

Specific Immune Response: is specific and relies in prior experiences and encounters with microbe. Specific substances are released to kill the microbe, which are called antigens.

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9
Q

How does intact skin function as a mechanical barrier?

A

It forms a physical barrier to the entrance of microbes.

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10
Q

What is the mucous membrane function, as a mechanical barrier?

A

Inhibits the entrance of many microbes, but not as effective as intact skin.

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11
Q

What is mucus’s function as a mechanical barrier ?

A

Traps microbes in respiratory and digestive tracts.

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12
Q

What are the hairs function, in terms of acting as a mechanical barrier?

A

They filter microbes and dust in the nose.

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13
Q

What are the cilia’s function, as a mechanical barrier?

A

Together with mucus, trap and remove microbes and dust from upper respiratory tract.

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14
Q

How do gastric juice act as a chemical barrier?

A

Destroy bacteria and most toxins in stomach.

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15
Q

How does the acid pH of skin act as a chemical barrier?

A

Discourages growth of many microbes.

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16
Q

What is a non-specific immune response?

A

It is present from birth, since a newborns immunity is not yet active. However the baby does receive some antibodies from the mother (passive immunity). At 18 months it develops it’s own active Immunity.

Quick response system effective against a verity of pathogens & foreign substances. Can be divided into 4 subclasses:
Inflammation, phagocytosis, natural killer cells & fever.

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17
Q

What is inflammation? (Non-Specific)

A

A local response to tissue damage. Which can be due to microbial invasion, cuts and other physical damage. Can also be caused by irritating corrosive chemicals.

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18
Q

How does inflammation work exactly?

A

Damaged cells in the dermis release the hormone histasine into the wounded area. It also releases other chemicals called prostaglandins. Histasine & prostaglandins induce the arterioles to vasodilate, thus increasing the blood flow towards damaged area. Also increase the permeability of the capillaries.

Oozing out of blood prevents further entry of microbes & transports platelets and plasma proteins towards the cut to heal the wound. Blood starts to cloth.

This increase in permeability and large amount of blow flow results in swelling, redness and increase in temperature of the damaged area. All this can lead to pain. It is also needed to let white blood cells squeeze through the pores. They will engulf microbes & digest them.

Macrophages are attracted to the injury area by chemicals released by the damaged cells and the microbes themselves.

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19
Q

What is pus?

A

The material that oozes out and collects around the heal and consists of microbes, tissue dermis & white blood cells that are both living and dead.

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20
Q

What is phagocytosis? (Non-Specific)

A

The process of engulfing and ingestion of particles by the cell or a phagocyte.

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21
Q

What are neutrophils?

A

The first white blood cells to arrive on site. They are able to squeeze through the capillary walls and move out in the tissue spaces.

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22
Q

What are macrophages?

A

They patrol in tissues and can found in liver, spleen and lymph nodes. They develop from monocytes.
On digestion by the macrophages some breakdown products are presented on the membrane of white blood cells to stimulate the action of the lymphocytes.

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23
Q

What are natural killer cells? (Non-Specific)

A

Are a type of cytotoxic lymphocytes that constitute a major component of the innate immune system.

NK play a mayor role in the rejection of tumours & cells infected by viruses. The cells kill by releasing small cytoplasmic granules of protein called perforin & granzyme that cause the target cells to die by apoptosis.

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24
Q

What is fever? (Non-Specific)

A

It’s also known as controlled hyperthermia. It’s a common medical sign characterised by an elevation of temperature above the normal range of 36.5 - 37.5 due to an increase in the body temperature regulatory set point.
This increase in set point triggers increased muscle tone and shivering.

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25
Q

What happens when you have a fever?

A

As a person’s temperature increases, there is, in general, a feeling of cold despite an increasing body temperature. Once the new temperature is reached, there is a feeling of warmth.

A fever is one of the body’s immune system response that attempt to neutralise a bacterial or viral infection, this increase in body temperature lowers the reproductive ability of microbes and gives time for the body to combat the infestation. The infected cells relapse a chemical known as interferon, that travel along the body to other cells to help them increase their resistance against viral attack.

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26
Q

What is a specific immune response?

A

When a particular antigen passes the body’s passive defences.
It involves cells and proteins within the blood and lymph that attach, disarm, destroy and remove foreign bodies.

It gives a highly effective, long lasting immunity against anything the body recognises as foreign. It respond to specific micro organisms and enhances the activity of the non-specific system.

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27
Q

There are 2 types of lymphocytes. Name them.

A

B cells and T cells.

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28
Q

How are white blood cells made?

A

They arise from pre-existing cells in the bone marrow.

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29
Q

where do the T cells migrate once formed?

A

To the thymus.

30
Q

Where do the B cells migrate once formed?

A

They remain in the bone marrow, but differentiate.

31
Q

What is the central feature in the specific immune system?

A

The ability to distinguish between self and non-self.

32
Q

How does the body distinguish between the self and non-self?

A

Every cells has complex molecules (proteins and glycoproteins) on its surface membrane which act as recognition devices and have specific shapes. These molecules are called antigens or immunoglobulins.

The immune system is usually tolerant to the body’s own antigens (self antigens) and does not attack against them.

33
Q

What is an autoimmune disease? Also give an example of one.

A

It is the breakdowns of the recognition system.

Eg AIDS, which result in self destruction of body parts.

34
Q

What occurs once a foreign organism enters the body? (Specific immune response)

A

The foreign organism (bacteria, viruses or even another persons cells) enter the body, the foreign antigens on the invading cells activate an immune response. The foreign antigens are called non-self antigens.

The immune system produces antibodies and specialised cells that attempt to destroy foreign cells & particles that have entered the body.

35
Q

There are 2 types of responses in the specific immune response. Name them.

A

Humoral (antibody) response: involving B cells.

Cell mediated immunity: involving T cells.

36
Q

What occurs during a humoral response? (B cells)

A

It is initiated by an activation phase. Where macrophages engulf and digest microbes (including their antigens) through a process called phagocytosis.

Some if the digested antigens are then displayed on the surfaces of the macrophages (epitopes). This display provides other cells of the immune system with an opportunity to recognise the invader and become activated. This is called antigen presentation.,

37
Q

What occurs during antigen presentation?

A

The macrophage selects T-helper cells and B cells that have membrane receptors that are complimentary in shape to the antigens exposed. This is known as clonal selection.

T helper Cells recognise and bind to the displayed antigens. This then intimates the next phase of the humoral response.

38
Q

The next phase in the humoral response, is the effector phase. What occurs during this stage?

A

Activates T cells trigger specific B cells to proliferate and release antibodies, these antibodies bind to the invader and fight infection.

This stage involves specific lymphocytes (white blood cells) that mature in the bone marrow. There are called B-lymphocytes. They can produce a specific antibody in response to a particular antigen.

39
Q

What is an antibody?

A

Is a type of globular protein that reacts with a specific antigen.

They are y shaped molecules composed of heavy chains and light chains, which are kept together by s-s bonds. The ends of the Y arms are the binding sites for an antigen.

40
Q

What occurs when a B-cell meets an antigen? (Humoral response)

A

It will dived through mitosis and after several generation will differentiate into plasma cells. All plasma cells are formed from one type of B cells and will secrete the same antibody.

The antibodies produced circulate in the blood and lymph or secrete antibodies onto the surfaces of mucous membranes. Eg lining in lungs.

41
Q

Different antibodies, work in different ways. Give a few examples of such.

A

Agglutination: makes pathogens clump together.
Antitoxins: neutralise the toxins produced by bacteria.
Lysis: digests the bacterial membrane, killing the bacterium.
Opsonisation: coats the pathogens in protein that identified them as foreign cells.

42
Q

What happens when an antigen is confronted for the first time?

A

B cells produce Memory B-cells as well as plasma cells, this is called primary response. This is usually slow. Taking days or even weeks to recruit enough plasma cells to bring an infection under control.

However, when a second invasion occurs, the response is quicker. Memory cells are involved in the secondary response & stick to and destroy antigens.

43
Q

What occurs during cell meditated response?

A

Involves cells that are specific to the antigens on the invading pathogens. The cells involved are lymphocytes called T-cells, which mature in the thymus. In the thymus, the T-cells develop surface receptors called T-cells receptors where they become programmed for the antigen of their specific enemy.

Many different kinds of T cells are produced which recognise, attach and destroy infected, mutant or foreign cells. After encountering a specific foreign antigen, T cells produce rapidly. However they do not produce antibodies like B cells.

44
Q

After the macrophage has ingested foreign material. What happens next?

A

The macrophages carry the foregoing cells to the T Helper and T Killer cells in the lump nodes, spleen and blood.

45
Q

What are Helper T-cells?

A

They recognised the non-self antigen (from foreign cells) that the macrophages display on their outer surface.
They recognise the antigens and stimulate B cells to produce antibodies. B cells will not reproduce and form plasma cells without the assistance from helper T cells.

Also secrete proteins (interleukin & lymphokines) that stimulate B and T cells to divide, where some of the cells become effector cells and memory T cells.
Activates Killer B cells.

46
Q

What do lymphokines stimulate?

A

Macrophages to engulf invading cells.

One of the proteins realised by T helper cells.

47
Q

What do interlukin stimulate?

A

Can stimulate cytotoxic T cells.

Other protein produced by T helper cells.

48
Q

What are cytotoxic killer T-cells?

A

They attack the body cells that have been infected by virus, bacteria or fungus.

They identify it’s antigen, where in this case a viral protein coat is left outside the infected cell, and kills the infected cell before the virus has time to replicate.
Kill the infected cells by secreting proteins (perforin) that lunch holes in the membrane of the cells and the contents ooze out.
Cannot kill isolated virus particles, as they need the viral antigen before they become activated.

49
Q

What are Natural Killer cells?

A

Have the same response as cytotoxic T cells, however they may attack tumour and other cancerous cells.

50
Q

What occurs during the end of the cell meditated response?

A

Once the T helper cells and T cytotoxic cells are activated, they divide many times, where some of the cells become effector T cells and others as merit cells, where they migrate to the lymph nodes to be activated quickly upon a second invasion.

51
Q

What are T-suppressor cells?

A

They play an important tole in regulating that action of the lymphocytes, where they can help prevent the immune system overreacting to a stimulus. It stops the action of both T & B lymphocytes.

52
Q

What is the lymphatic system?

A

When the B and T cells develop in the bone marrow and thymus respectively, they enter the blood stream, then leave it, and move around the body in the lymphatic system.

The immune system contains a number of lymphoid tissues and organs, Eg spleen, tonsils and lymphnodes. These are connected to a network of vessels (similar tot that of the blood)

53
Q

What do lymphatic vessels contain?

A

Lymph, which drains from nearby tissues. Memory B and T cells circulate in the lymph, ready to react with their antigen. Antigens that enter the body are carried by macrophages to a lymphatic organ, where there is a high concentration of white blood cells, such as T helper and T cytotoxic cells.

54
Q

What’s a common sign indicating that you have an infection?

A

You may noticed that your glands (lymph nodes) may be swollen and sore.

55
Q

What are antibiotics? Give a few examples of when we would use them.

A

Also known as antibacterials, they are drugs used to treat infections cause by bacteria.
Illness such as tuberculosis, salmonella, syphilis and some forms of meningitis are caused by bacteria. Some bacteria are not harmful, and some are even good for us.

56
Q

When are antibiotics needed?

A

Before bacteria can multiply and cause symptoms, our immune system can usually destroy them. We have specific listed white blood cells that attack harmful bacteria. Even if symptoms do occur, our immune system can usually cope and fight off infection.

There are some occasion however, when it’s all too much and our bodies need help. This is when we should use antibiotics.

57
Q

What was the first antibiotic?

A

Penicillin.

58
Q

How do antibiotics work?

A

Although there a number of different types of antibiotics. They all work in one of two ways:
A bactericidal antibiotic kills the bacteria. Eg penicillin. It usually either interferes with the formation of the bacterium cells walls or its contents
A bacteriostatic stops bacteria from multiplying.

59
Q

What are antibiotics for?

A

Treatment of an infection caused by bacteria. They target only bacteria - they do not attack other organisms, such as fungi or viruses.

60
Q

What are most upper respiratory tract infections caused by?

A

Infections such as the common cold and sore throats are generally caused by viruses. Hence why antibiotics don’t work.

61
Q

Why is it bad to overuse antibiotics?

A

If they are overused or used incorrectly there is a chance that the bacteria will become resistant.
Causing antibiotics to become less effective against that type of bacterium.

62
Q

What is the difference between a broad-spectrum and narrow-spectrum antibiotic?

A

A broad spectrum can be used to treat a wide range of infections.
Whereas a narrow spectrum is only effective against a few types of bacteria.

63
Q

What is prophylactic use of bacteria?

A

Antibiotics given beforehand to prevent infection, for example in the case of surgery.

64
Q

What are vaccines?

A

They are prepared with biological properties and administered through injections or oral suspensions.
They help protect the body from diseases by improving or creating immunity to the particular disease in the vaccine given.

65
Q

How long have vaccines been around?

A

Hundreds or years. It fact it was first used to protect against smallpox.
It was noted that individuals exposed to smallpox, rarely got smallpox, which furthered the investigation into injecting a small amount of the disease to help develop the immunity.

66
Q

There are 4 types of vaccines. Please name them.

A

A live vaccine: common live vaccines are for rubella, mumps, measles and yellow fever.
Vaccines containing microorganisms that have been killed through heat or with chemicals. Eg flu, hepatitis A, bubonic plague & cholera.
Toxoids: Eg diphtheria and tetanus.
Subunit: include portions of the microorganism, which can create an immune response too. Eg HPV.

67
Q

How do vaccines work?

A

Vaccines create immunity because when they are introduced into the body, the body reacts to the antigen as if it were potentially harmful.
Antibodies will be formed to react with the antigens and the gene form to fight that antigen will be stored in memory cells.
Therefore, when the body is exposed to the real disease it will have the needed antibody to kill it.

68
Q

What does AIDS stand for? and how is it caused?

A

Acquired Immunodeficiency Syndrome.

It is caused by HIV (human Immunodeficiency Virus)

69
Q

What is AIDS?

A

It is a conditions whereby the body’s specific defence system against all infectious agents no longer functions properly.

There is a focused loss over time of immune cell function which allows intrusion by several different infectious agents, the results of which is loss of the ability of the body to fight infection and the subsequent acquisition of diseases such as pneumonia.

70
Q

How does HIV affect the immune system? Part 1

A

The first stage of HIV contractions is acute HIV infection. Since HIV is comprised both RNA and DNA elements, it has the ability to directly infect human cells and utilise their components (in 1 of the 46 chromosomes) to replicate parts if the HIV structure.

The immune system, is mainly compromised of 2 cell types. B cell and T cells. The 2 particular types of T cells, helper and cytotoxic, are affected in distinct ways by the virus, leading to a constant struggle between virus replication efforts & immune system T cell reproduction.

71
Q

How does HIV affect the immune system? Part 2

A

The helper T cells function as the body alarms system to imitate the cytotoxic cells, which attack and kill those cells in the body infected by the intruding virus.
Because HIV attacks there helper T cells immediately upon contraction, the immune system response coma abilities gradually deteriorate though the duration of infection.
As the body generated new T cells, the reproducing HIV strand will target! infect and kill the new immune system elements.

72
Q

What happens in the end of HIV?

A

The fight turns into a cycle of cell infection, death and reproduction for approximately 10 years until the body is so severely weakened by an inability to produce T cells that it succumbs to weak viral and bacterial organism that are normally simple work for the base human immune system.
Once this has occurred, the ensuing condition is called AIDS.

Biology (10 decks)

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