Chapter 43: The Immune System Flashcards

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1
Q

Pathogen

A

Bacterium, fungus, virus, or other disease disease-causing agent

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2
Q

Immune System

A

The body’s defenses that enables an animal to avoid/inhibit infection

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3
Q

Innate Immunity

A
  • Includes barrier defenses
  • Recognition relies on a small set of receptor proteins that bind to molecules/structures absent from animals but common to a group of viruses, bacteria, or other molecules
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4
Q

Adaptive Immunity

A

Molecular recognition relies on a vast arsenal of receptors, each of which recognizes a feature typically found only on a particular molecule in a particular pathogen

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5
Q

Lysozyme

A

Enzyme that breaks down bacterial cell walls

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6
Q

Phagocytosis

A
  • Type of endocytosis
  • Large particulate substances or small organisms are taken up by a cell
  • Carried out by some protists and by certain animals
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7
Q

Toll-Like Receptor

A
  • Membrane receptor on a phagocytic white blood cell

- Binds to fragments of molecules normally absent from the vertebrate body but characteristic of a set of pathogens

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8
Q

Neutrophil

A
  • Phagocytic cell
  • Circulates in the blood
  • Attracted by signals from infected tissues
  • Engulf and destroy infecting pathogens
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9
Q

Macrophages

A
  • “big eaters”
  • Larger phagocytic cells
  • Some migrate throughout the body
  • Some reside permanently in organs and tissues
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10
Q

Dendritic Cells

A
  • Mainly populate tissues that contact the environment

- Stimulate adaptive immunity against pathogens they engulf

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11
Q

Natural Killer Cells

A
  • Circulate through the body
  • Detect abnormal array of surface proteins characteristic of some virus-infected and cancerous cells
  • Release chemicals that promote cell death
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12
Q

Interferons

A

Proteins that provide innate defenses by interfering with viral infections

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13
Q

Complement System

A
  • About 30 proteins in blood plasma

- When activated, cause a cascade of biochemical reactions that can lead to lysis

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14
Q

Inflammatory Response

A

Changes brought about by signaling molecules released upon injury or infection

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15
Q

Histamine

A

Inflammatory signaling molecule found in connective tissue

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16
Q

Mast Cells

A
  • Densely packed vesicles

- Produce histamine and other molecules that trigger inflammation in response to infection and in allergic reactions

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17
Q

Lymphocytes

A
  • Type of white blood cell
  • Mediates immune responses
  • Main classes are B cells and T cells
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18
Q

Thymus

A
  • Organ in the thoracic cavity above the heart

- Where T cells mature

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19
Q

T cells

A
  • Lymphocytes that migrated to the thymus to mature
  • Includes effector cells for the cell mediated immune response and helper T cells required for both types of adaptive immunity
20
Q

B Cells

A
  • Lymphocytes that complete their development in the bone marrow
  • Become effector cells for the humoral immune response
21
Q

Antigen

A

Substance that causes B/T Cell response

22
Q

Antigen Receptor

A

Protein where B/T cell binds to antigen

23
Q

Epitope

A

Small accessible portion of an antigen that binds to an antigen receptor

24
Q

Heavy Chains

A
  • 1 of 2 types of polypeptide chains that make up an antibody molecule and B cell receptor
  • Consists of a variable region, which contributes to the antigen binding site, and a constant region
  • Longer than light chains
25
Q

Light Chains

A
  • 1 of 2 types of polypeptide chains that make up an antibody molecule and B cell receptor
  • Consists of a variable region, which contributes to the antigen binding site, and a constant region
  • Shorter than heavy chains
26
Q

Antibody/Immunoglobulin (Ig)

A
  • Protein secreted by a B cell activated by an antigen

- Secreted (not membrane bound)

27
Q

Major Histocompatibility Complex (MHC) Molecule

A
  • Host protein that functions in antigen presentation

- Foreign MHC molecules on transplanted tissue can trigger T cell responses that may lead to rejection of the transplant

28
Q

Effector Cells

A
  • Short-lived cells

- Take effect immediately against the antigen and any pathogens with that antigen

29
Q

Plasma Cells

A
  • Effector forms of B cells

- Secrete antibodies

30
Q

Memory Cells

A
  • Long-lived cells

- Can give rise to effector cells if the same antigen is met

31
Q

Clonal Selection

A

Meeting with an antigen selects for a lymphocyte to divide and produce a clonal population for a certain epitope

32
Q

Primary Immune Response

A

B and T cells give rise to their effector forms 10-17 days after initial exposure

33
Q

Secondary Immune Response

A
  • Faster, has a greater magnitude, and more prolonged than primary immune response
  • Unique to adaptive/acquired immunity
34
Q

Humoral Immune Response

A
  • Occurs in blood and lymph

- Antibodies help neutralize or eliminate toxins/pathogens in the blood/lymph

35
Q

Cell-Mediated Immune Response

A

Specialized T cells destroy infected host cells

36
Q

Helper T Cell

A

Triggers both the humoral and cell-mediated immune response

37
Q

Antigen-Presenting Cell

A
  • Can be dendritic cell/B cell/macrophage

- Displays an antigen to show it’s infected so that T cells can begin the immune response

38
Q

Cytotoxic T Cells

A

Utilize toxic proteins to kill cells infected by viruses or other intracellular pathogens before pathogens fully mature

39
Q

Active Immunity

A

Defenses that arise when a pathogen infects the body and prompts a primary or secondary immune response

40
Q

Passive Immunity

A
  • Antibodies in the recipient are produced by someone else
  • Lasts only a few weeks to a few months
  • Ex: mothers passing antibodies through breastmilk
41
Q

Immunization

A
  • Process of generating a state of immunity by artificial means
  • In vaccination: inactive/weakened form of a pathogen is administered, inducing B and T cell responses and immunological memory
  • In passive immunization: antibodies specific for a particular pathogen are administered, conferring immediate but temporary protection
42
Q

Monoclonal Antibodies

A
  • Prepared from a single clone of B cells

- Identical and specific for the same epitope on an antigen

43
Q

Autoimmune Disease

A
  • Loss of self tolerance
  • The body attacks itself
  • Ex:
    - Lupus
    - allergies
    - asthma
    - arthritis
    - psoriasis
    - Crohn’s disease
44
Q

Human Immunodeficiency Virus (HIV)

A
  • Pathogen that causes AIDS
  • Infects Helper T cells
  • Evolves within the body
45
Q

Acquired Immunodeficiency Syndrome (AIDS)

A
  • Impairment in immune responses

- Leaves the body susceptible to infections and cancers that a normal immune system would typically defeat