Microbiology Chapter 15

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1

Specific immunity

The ability of a vertebrate to recognize and defend against distinct species or strains of invaders

2

Axenic

Having only one organism present

3

Dermis

The layer of the skin deep to the epidermis and containing hair follicles, glands, and nerve endings

4

Monocyte

Present in the tissues; become macrophage (when mature). Defense against chronic infection

5

Fever

Body temperature above 37°C

6

Sebum

Oily substance secreted by the sebaceous glands of the skin that lowers pH

7

Adherence

Process by which phagocytes attach to microorganisms through the binding of complementary chemicals on the cytoplasmic membranes

8

Leukocyte

White blood cell

defend against invaders

Lymphocytes and phagocytes

9

Normal microbiota

Microorganisms that colonize the surfaces of the human body without normally causing disease. They may be resident or transient.

10

Erythrocyte

Red blood cell.

transport oxygen and carbon dioxide

11

Chronic inflammation

Type of inflammation that develops slowly, lasts a long time, and can cause damage (even death) to tissues resulting in disease

12

Macrophage

Mature form of monocyte, which is a phagocyte of bacteria, fungi, spores, and dust, as well as dead cells

engulf and digest microorganisms

activate T cells

13

NOD protein

In innate immunity, intracellular receptor for microbial component

14

Eosinophilla

An abnormal blood condition in which the number of eosinophils is greater than normal

15

Chemotactic factors

Chemicals, such as peptides derived from complement and cytokines that attract cells.

16

Adaptive immunity

Resistance against pathogens that acts more effectively upon subsequent infections with the same pathogen.

17

Pathogen-associated molecular patterns [PAMPs]

are the molecular patterns that are displayed on various pathogens. Immune cells recognize these patterns and initiate the innate immune response.

18

Gamma interferons [IFN-y]:

Interferon produced by T lymphocytes and NK lymphocytes; activates macrophages and neutrophils days after an infection

19

Eosinophil

Type of granulocyte that stains red to orange with the acidic dye eosin.

Kill antibody-coated parasites

20

Leukotrienes

Inflammatory chemicals released from damaged cells that increase vascular permeability

21

Pyrogen

Chemical that triggers the hypotha-lamic “thermostat” to reset at a higher temperature, inducing fever.

22

Mast cells

Specialized cells located in connective tissue that release histamine when they are exposed to complement [when damaged]

23

Diapedesis

(emigration) Process whereby leukocytes leave intact blood vessels by squeezing between lining cells.

24

Dendritic cells

Cells of the epidermis and mucous membranes that devour pathogens.

present antigens to T cells

25

Agranulocyte

Type of leukocyte having a uniform cytoplasm lacking large granules.

26

Opsonin

Antimicrobial protein that enhances phagocytosis

27

Complement system

Set of blood plasma proteins that acts as chemotactic attractants, trigger inflammation and fever, and ultimately effect the destruction of foreign cells.

28

Margination

Process by which leukocytes stick to the walls of blood vessels at the site of infection.

29

Membrane attack complexes [MACs]

The end products of the complement cascade, which form circular holes in a pathogen's membrane.

30

Calor

heat

31

Abscess

An isolated site of infection such as a pimple, boil, or pustule

32

Phagolysosome

Digestive vesicle formed by the fusing of a lysosome with a phagosome.

33

Stem cells

Generative cells capable of dividing to form daughter cells of a variety of types

34

Microbial anatagonism

(microbial competition) Normal condition in which established microbiota use up available nutrients and space, reducing the ability of arriving pathogens to colonize

35

Natural Killer [NK] lymphocyte

Type of defensive leukocyte of innate immunity that secretes toxins onto the surfaces of virally infected cells and neoplasms.

36

Antimicrobial peptide

(defensin) Chain of about 20 to 50 amino acids that acts against microorganisms.

37

Dolor

pain

38

Prostaglandins

Inflammatory chemicals released from damaged cells that increase vascular permeability

39

Lymphocyte

Type of small agranulocyte, which originates in the red bone marrow and has nuclei that nearly fill the cell

40

Beta interferons [IFN- B]

Interferons secreted by virally infected fibroblasts within hours after infection.

41

Antiviral proteins [AVPs]

Proteins triggered by alpha and beta interferons that prevent viral replication.

42

Phagosome

A sac formed by a phagocyte's pseudopods; an intracellular food vesicle.

43

Basophil

Type of granulocyte that stains blue with the basic dye methylene blue.

44

Species Resistance

Property that protects a type of organism from infection by pathogens of other, very different organisms

45

Rubor

Redness

46

Opsonization

The coating of pathogens by proteins called opsonins, making them more vulnerable to phagocytes

47

Alpha interferons [IFN-a}:

Interferons secreted by virally infected monocytes, macrophages, and some lymphocytes within hours after infection.

48

Microglia

Fixed macrophages of the nervous system

49

Histamine

Inflammatory chemical released from damaged mast cells that causes vasodilation of capillaries

50

Granulocyte

Type of leukocyte having large granules in the cytoplasm

51

Acute inflammation

Type of inflammation that develops quickly, is short lived, and is usually beneficial.

52

Epidermis

The outermost layer of the skin

53

Lysozyme

Antibacterial protein secreted in sweat

54

Bradykinin

Peptide chain of nine amino acids that is a potent mediator of inflammation.

55

Platelet

Cell fragments involved in blood clotting

initiate blood clotting

56

Innate immunity

Resistance to pathogens conferred by barriers, chemicals, cells, and processes that remain unchanged upon subsequent infections with the same pathogens.

57

Toll-like receptors [TLRs]

Integral membrane proteins that bind to specific microbial chemicals.

58

Interferons [IFNs]

Protein molecules that inhibit the spread of viral infections

59

Neutrophil

Type of granulocyte that stains lilac with a mixture of acidic and basic dyes.

60

Chemokine

An immune system cytokine that signals leukocytes to rush to the site of inflammation or infection and activate other leukocytes

61

Plasma

The liquid portion of blood

62

Phagocytes

Cells, often leukocytes that are capable of phagocytosis

63

Wandering macrophage

Type of macrophage that leaves the blood via diapedesis to travel to distant sites of infection.

64

Siderophore

An iron-binding molecule released by some bacteria and fungi

65

Humoral response

  • Involves B cells.
  • Results from the production of antibodies.
  • Defends against free bacteria, viruses, and toxins that are found in the blood or lymph.
  • Word derivation:
    • “Humor” is a medieval term for body fluid.
    • This immunity is based on pathogens and the resulting antibodies that are floating in the blood and lymph (body fluids).
66

Cell-mediated response

  • Involves T cells.
  • Does not use antibodies.
  • Defends against any non-self cells, including infected cells containing pathogens.

T cells must accomplish a double recognition process: they must recognize both self (an HLA molecule of a body cell) and nonself (antigen) at the same time.

This system does not attack pathogens directly, like humoral immunity—it attacks cells that have already been attacked

67

Formed Elements

Cells and cell fragments suspended in blood plasma

68

External defense

first line of defense of the body is attributable to the epithelial tissues of the body that cover the outer surface of the body (the skin) and those that line the body cavities (such as the GI tract and respiratory tract) that come into contact with the external environment

69

Internal cellular defenses

Phagocytic cells

-Neutrophils

-Monocytes

-Eosinophils

-Dendritic cells

Natural Killer Cells: Non-specific-->Perforins

-->Apoptosis

interferons: antimicrobial proteins

70

Internal Chemical defenses

inflammatory response

71

Inflammatory response:

occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling.

72

Defensins

small cysteine-rich cationic proteins found in both vertebrates and invertebrates. They have also been reported in plants. They are, and function as, host defense peptides. They are active against bacteria, fungi and many enveloped and nonenveloped viruses

73

Interlukin 1

is a group of 11 cytokines, which plays a central role in the regulation of immune and inflammatory responses to infections or sterile insults

74

Differential White Blood Cell Count

Lab technique that indicates the relative numbers of leukocytes.

75

Artificially acquired active immunity

person is given a vaccine

76

inflammatory response breakdown

  • Word derivation: inflammo—to set on fire.
  • Damage to tissue occurs (like a break in the skin).
  • White blood cells (basophils and mast cells) in the tissue are stimulated to release histamine.
  • Histamine causes the capillaries to dilate and become leaky.
    • Results in increased blood flow to the area.
    • Blood plasma and phagocytes leak out of the capillaries and into the infected tissue.
    • This causes the site of injury to swell, become red, warm, and tender.
  • Complement proteins are released to attract phagocytes.
  • Phagocytes engulf microbes and infected/damaged cells.
77

Inflammation functions

  • To destroy and remove pathogens and debris.
  • To confine pathogens; prevent spread of infection.
  • To repair or replace damaged tissue (sets stage for wound repair).
78

nonspecific response or innate immunity

ready to respond immediately and at all times in a nonspecific way

  • Its main components are:
    • The inflammatory response
    • Phagocytosis
    • Antimicrobial proteins
    • Natural killer cells
79

Explain the benefits of fever, and how it may have an adverse effect on the body

Fever, or an abnormally high body temperature, is a systemic response to a bacterial or viral infection.

induced by chemicals called pyrogens

A chill indicates a rising body temperature; crisis (sweating) indicates that the body’s temperature is falling.

A rise in body temperature, or fever, can happen with some infections. This is actually an immune system response. A rise in temperature can kill some microbes. Fever also triggers the body’s repair process.

• Enhances the performance of phagocytes and the process of tissue repair

80

Use your knowledge of how fever is initiated in the body and propose a mechanism of action for aspirin and ibuprofen

Fever is a common response to infection: a higher body temperature can heighten the immune response and provide a hostile environment for pathogens.

Body temperature increases as a protective response to infection and injury. An elevated body temperature (fever) enhances the body’s defense mechanisms, although it can cause discomfort

Drugs used to lower body temperature

81

Physical and chemical factor that helps fight microbial entry-skin

great physical barrier, oils (sacks of keratin on epidermis lubricate, metabolized by microbes as a food source) keratin is a tight water proof barrier that is like armor and is hard to digest , natural flora (staph, strep, candida albicans) occupies niches that make it difficult for pathogens to take hold. , pH (4-6) discourages the growth of many pathogens, sweat contains salt, urea and lysozyme, .

82

Physical and chemical factor that helps fight microbial entry-eye

tears wash away microbes

lysozome

83

Physical and chemical factor that helps fight microbial entry-respiratory tract

The epithelial lay secretes a fluid called mucus, a slightly viscous glycoprotein produced by goblet cells of a mucous membrane. It prevents the tracts from drying out and serves as a mechanical barrier to microbes

84

Physical and chemical factor that helps fight microbial entry-digestive tract

The epithelial lay secretes a fluid called mucus, a slightly viscous glycoprotein produced by goblet cells of a mucous membrane. It prevents the tracts from drying out and serves as a mechanical barrier to microbes

85

Physical and chemical factor that helps fight microbial entry-urinary tract

The epithelial lay secretes a fluid called mucus, a slightly viscous glycoprotein produced by goblet cells of a mucous membrane. It prevents the tracts from drying out and serves as a mechanical barrier to microbes

chemical= lysozome; acids

86

Phagocytosis steps

ingestion of microbe by phagocyte
formation of phagosome
fusion of the phagosome with a lysosome to form a phagolysosome
digestion of ingested microbe by enzymes
formation of residual body containing indigestible material
discharge of waste materials
phagocytes migrate to a site of infection and can destroy the infecting bacteria. The phases of phagocytosis are chemotaxis, adherence, ingestion, and digestion.

87

Explain what a complement is and how it contributes to the body’s defenses

Composed of twenty different proteins that “complement” other defenses.

Help activate the inflammatory response and attract phagocytes to the site of infection.

Attach to microbes, helping phagocytes destroy them.

Help lyse the cell membrane of microbes.

coat a microorganism and provide binding sites, enabling macrophages and neutrophils to phagocytize the organism

88

Explain what phagocytosis is and how it contributes to the body’s defense against microorganisms.

The most important part of the second line of defense

Engulf microbes and infected/damaged cells.

Phagocytes confront microorganisms that breach the external barriers.

ingest and destroy all microbes that pass into body tissues. For example macrophages are cells derived from monocytes (a type of white blood cell). Macrophages leave the bloodstream and enter body tissues to patrol for pathogens.