Chapter 37: Human Defence System Flashcards

1
Q

What is a pathogen?

A

a disease causing organism

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2
Q

What is immunity?

A

the ability to resist disease

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3
Q

What are the two defence systems called?

A

general defence system

specific defence system

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4
Q

What does the general defence system do?

A

acts against all pathogens

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5
Q

What is the first line of defence in the general defence system?

A

consists of skin, mucous membranes, secretion of skin

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6
Q

What are the 3 possible 2nd line of defence in the general defence system?

A

white blood cells
defence proteins
inflammation

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7
Q

explain how white blood cells act as a line of defence.

A

attracted to chemicals of invading micro organisms

surround and ingest pathogens

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8
Q

What is a phagocyte?

A

a cell that ingests another cell

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9
Q

What is a macrophage?

A

a large phagocyte

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10
Q

What is phagocytosis?

A

when a cell surrounds and ingests another cell

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11
Q

Explain how defence proteins work.

A

activated by infection

prevent multiplication and limit spread of viruses

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12
Q

Explain how inflammation works.

A

infection causes blood capilleries to diallate
this brings more white blood cells to an area
those cells then fight infection

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13
Q

What does the specific defence system do?

A

system attacks particular invaders

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14
Q

How does the specific defence system work?

A

produces antibodies or white blood cells that engulf a particular pathogen

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15
Q

What are monocytes?

A

white blood cells that become macrophages

they engulf invaders

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16
Q

How do monocytes work?

A

they engulf invaders

once engulfed part of the invader remains on the surface of the macrophage

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17
Q

What is an antigen?

A

a foreign molecule on the surface of a monocyte that stimulates the production of antibodies

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18
Q

What are lymphocytes?

A

white blood cell that produces antibodies as a result of antigens

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19
Q

How do allergies arise?

A

our bodies produce antibodies against non-invaders

the body perceives a harmless substance to be an invader

20
Q

What is induced immunity?

A

using antibodies to resist specific diseases

21
Q

What is active immunity?

A

antibodies produced in a persons body

22
Q

What is passive immunity?

A

antibodies from another organism enter a persons body

23
Q

What is natural active immunity?

A

pathogens enter in a natural manner and antibodies produced as a result of this e.g. catching a cold

24
Q

What is artificial active immunity?

A

pathogens are introduced into the body as a vaccine so that antibodies can be produced

25
Q

What is natural passive immunity?

A

getting antibodies from another organism in a natural way e.g. breast milk from mother to baby

26
Q

What is artificial passive immunity?

A

getting antibodies in a non natural way e.g. antibody injections

27
Q

What is an antibody?

A

proteins that are produced by lymphocytes in response to an antigen

28
Q

Why do adults have a greater number of antibodies than children?

A

they have been exposed to more pathogens

29
Q

Explain the antibody-antigen reaction.

A

there is a precise fit between the antigen and the antibody

each antibody is complimentary to the antigen

30
Q

How can lymphocytes be identified?

A

They have a large round nucleus

31
Q

Where are lymphocytes made?

A

Bone marrow

32
Q

What are the two types of lymphocytes?

A

B-cells

T-cells

33
Q

Where do b-cells mature?

A

Bone marrow

34
Q

What do b-cells do?

A

Recognize a specific antigen and produce the antibody to fight it

35
Q

What do b-cells usually attack?

A

Bacterial infections and some virus infections

36
Q

Explain how b-cells work.

A

Comes into contact with antigen
Multiplies and produces large amount of antibodies
Antibodies attach to antigens
Cell engulfed by pathogen or cell complement system is activated

37
Q

What are memory b-cells?

A

The remaining b-cells that produce a specific antibody that have already overcome an infection

38
Q

What are the advantages of memory b-cells? (3)

A

Produces antibodies to small amount of antigens
Produces antibodies faster
Produces greater numbers of antibodies than first time

39
Q

How much faster do memory b-cells work than regular b-cells?

A

B-cells produce antibodies in about 14 day

Memory b-cells produce them in 5

40
Q

Where do t-cells mature?

A

Thymus gland

41
Q

What do t-cells do?

A

Fight off viruses and some bacteria

42
Q

What are the 4 types of t-cells?

A

Helper
Killer
Suppressor
Memory t-cells

43
Q

What do helper t-cells do?

A

Recognize antigens and stimulate the multiplication of the correct b-cell
Stimulates killer t-cells to reproduce

44
Q

What do killer t-cells do?

A

Attack and destroy abnormal body cells (cancer,virus)

45
Q

How do killer t-cells work?

A

Release a protein perforin
Forms pores in the membrane of the cell
Water enters and the cells burst

46
Q

What are suppressor t-cells?

A

Stimulated by specific antigens
Slow growth
They become active after the pathogen has been destroyed
Inhibits other immune response

47
Q

What are memory t-cells?

A

Stimulate memory b-cells to produce large amounts of antibodies if the same pathogen reenters