Lymphatic/Immune 2 Flashcards Preview

Anatomy II > Lymphatic/Immune 2 > Flashcards

Flashcards in Lymphatic/Immune 2 Deck (68):
1

Mobilization of Defenses

Leukocytes deployed

2

Margination

Leukocytes adhere to blood vessel walls

3

Diapedesis

Leukocytes squeeze between endothelial cells into tissue space

4

Containment and Destruction of Pathogens

Fibrinogen in tissue clots to trap microbes
Heparin prevents clotting at side of injury
Neutrophils respond and kill microbes via phagocytosis

5

Tissue Cleanup

1. Monocytes arrive in 8-12 hours and become macrophages
2. Edema slows venous flow and increases lymphatic flow to remove bacteria and debris
3. Pus is formed

6

Tissue Repair

Blood platelets and endothelial cells secrete cytokine PDGF that stimulates fibroblasts to multiply and synthesize collagen

7

Pus

Dead phagocytes, damaged tissue cells, and fluid

8

Abscess

Accumulation of pus in a confined space not open to the outside

9

Ulcer

Open sore

10

Immunity

Body's ability to defend itself against specific foreign material or organisms

11

Immune Specificity

Recognize self and nonself

12

Immune Memory

2nd encounter produces even more rigorous response

13

T Cells

Mature in the thymus
NK cells attack antigens
Effective against fungi, viruses, parasites, cancer, and tissue transplants

14

B Cells

Mature in the bone marrow
Antibody-mediated response
Effective against bacteria

15

Antigens

Molecules or bits of foreign materials

16

Antigen Immunogenicity

Ability to provoke immune responses

17

Antigen Reactivity

Ability to react to cells or antibodies

18

Chemical Nature of Antigens

Large, complex molecules, usually proteins

19

Epitopes

Small part of antigen that triggers immune response

20

Hapten

Smaller substance that cannot trigger an immune response unless attached to a body protein
Lipid of poison ivy

21

MHC-I Molecules

Built into cell membrane of all cells except for red blood cells

22

MHC-II Molecules

Markers seen only on membrane of antigen presenting cells
(Macrophages, B cells, thymus cells)

23

If cell is infected with virus...

MHC-I contains bits of virus marking cell so T Cells recognize

24

If antigen presenting cells (macrophages or B cells) ingest foreign proteins...

They will display as part of MHC-II

25

Histocompatibility Testing

Similarity of MHC antigens on body cells of different individuals
Tissue typing must be done before any organ transplant
Can help identify biological parents

26

Pathways of Antigen Processing

B and T cells must recognize a foreign antigen before beginning their immune response
B cells can bind to antigen in extracellular fluid
T cells can only recognize fragments of antigens that have been processed and presented to them as part of a MHC molecule

27

Cytokines

Small protein hormones involved in immune responses
Secreted by lymphocytes and antigen-presenting cells

28

Lymphocytes

80% T Cells (cell mediated): involves activation of phagocytes, T Cells
15% B Cells (antibody mediated): antibody production
5% NK cells (nonspecific immunity)

29

T Lymphocytes

Immunocompetent cell: antigen receptors in place

30

Negative Selection of T Cells in Thymus

1. Must bind to reticular epithelium cell
2. Must not react to self antigens
Failing either will result in clonal deletion or anergy
1/100 emerge immunocompetent

31

Clonal Deletion

Destruction of offending T Cell clone

32

Anergy

Inactive state, alive but unresponsive

33

Positive Selection of T Cells in Thymus

1. Recognize MCH or reticular epithelium cell
2. Do not react to self antigens
Divide rapidly and form a clone of T Cells with identical receptors for antigen
Only 2% pass

34

Cellular Immunity

T Lymphocytes attack and destroy foreign cells and diseased host cells

35

Cytotoxic T Cells

Carry out attack
Display CD8 on surface
Recognize antigen fragments associated with MCH-I molecules

36

Regulatory T Cells

Limit cell mediated attack

37

Memory T Cells

Provide immunity from future exposure to antigen

38

Cytotoxic T Cell Recognition

Antigen presentation by MHC-I proteins

39

Cytotoxic Elimination of Invaders

1. Secrete granules containing perforin that punch holes in large cells
2. Secretes lymphotoxin that activates enzymes in the target cell, causing its DNA to fragment
3. Secretes gamma-interferon to activate phagocytic cells

40

Helper T Cells

Display CD4 on surface
Costimulates all other lymphocytes and secretes cytokines

41

T Cell Activation

Role of MHC-II proteins
Found only on antigen presenting cells
Stimulate helper T cells

42

T Cell Activation

1. Binding of helper T cells (CD4 cells) to abnormal peptides ingested and displayed on MCH-II
2. Costimulation via a cytokine

43

Attack Phase of Helper T Cells

Secrete interleukins
Coordinate humoral and cellular immunity

44

Memory T Cells

T Cells from a clone that did not turn into cytotoxic T Cells during a cell-mediated response

45

T Cell Recall Response

Available for swift response if a 2nd exposure should occur

46

Recognition T Cells

As pathogen disappears, slows down immune reaction
Prevents autoimmune diseases

47

Antibody-Mediated Immunity

1. Millions of different B Cells that can recognize different antigens and respond
2. B Cells sit and let antigens be brought to them
3. Once activated, differentiate into plasma cells
4. Antibodies circulate in lymph and blood

48

Antibody Structure

Glycoproteins called immunoglobins
4 polypeptide chains (2 heavy and 2 light)
IgG, IgA, IgM, IgD, and IgE tips form antigen binding sites

49

IgA

Monomer in plasma
Dimer in mucus, saliva, tears, milk, intestinal secretions
Prevents adherence to epithelia

50

IgD

Monomer
B Cell membrane antigen receptor

51

IgE

Monomer
Tonsils, skin, mucus membranes
Stimulates release of histamines and attracts eosinophils

52

IgG

Monomer
75-85% circulating
Crosses placenta to fetus
Secondary immune response
Binds complement proteins

53

IgM

Monomer
B Cell membrane
Antigen receptor
Pentamer in plasma
Agglutination

54

Somatic Recombination

Shuffling DNA segments to form new combinations of base sequences to produce antibody genes

55

Antibody Actions

1. Neutralization of antigen by blocking effects of toxins or preventing its attachment to body cells
2. Immobilize bacteria by attacking cilia/flagella
3. Agglutinate and precipitate antigens by cross-linking them, causing clumping and precipitation
4. Complement activation
5. Enhancing phagocytosis through precipitation, complement activation, or opsonization

56

Monoclonal Antibodies

Antibodies against a particular antigen can be harvested from the blood

57

Primary Immune Response

First exposure to antigen response is steady and slow
Memory cells may remain for decades

58

Secondary Immune Response with Second Exposure

Thousands of memory cells proliferate and differentiate into plasma cells and cytotoxic T cells
Recognition and removal occurs quickly

59

Natural Active Immunity

Produces memory cells
Production of one's own antibodies or T Cells as a result of infection or natural exposure to antigen

60

Artificial Active Immunity

Produces memory cells
Production of one's own antibodies or T Cells as a result of vaccination

61

Natural Passive Immunity

Through placenta or milk
Temporary, fetus acquires antibodies from mother

62

Artificial Passive Immunity

Snakebite, rabies, tetanus
Temporary, injection of immune serum (antibodies)

63

Hypersensitivity

Excessive immune reaction against antigens that most people tolerate (allergens)

64

Asthma

Most common chronic illness in children
Inhaled allergens, histamines, dyspnea

65

Anaphylactic Shock

Bronchial constriction, dyspnea, vasodilation, shock, death
Treatment is epinephrine

66

Type II Hypersensitivity

IgG or IgM binds to antigens or cell surface receptors to lyse or overstimulate

67

Type III Hypersensitivity

Widespread antigen-antibody complexing
Complexes trigger intense inflammation

68

Type IV Hypersensitivity (Delayed)

12 to 72 hour delay
APC's in lymph nodes display antigens to helper T cells, which secrete interferon and lymphokines that activate cytotoxic T cells and macrophages