CHAPTER 22 Flashcards

1
Q

Lymph

A

Fluid similar to plasma (without plasma proteins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Lymphatic Vessels

A

a. lymphatic capillaries
b. lymphatic trunks
c. lymphatic ducts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cells in the lymphatic system

A

lymphocytes, phagocytes, other cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Lymphoid tissues

A

EX

a) tonsils
b) MALT (mucosa associated lymphatic tissue)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Lymphoid organs

A

spleen, thymus, lymph nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the lymphatic system do?

A

Protect us against disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do lymphatic system calls respond to?

A

Pathogens (viruses, bacteria, fungi, parasites)
Toxins
abnormal body cells such as cancers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is immunity, and what is involved in the immune system?

A

immunity is the ability to resist infection and disease

all cells and tissues are involved in production in immunity, NOT just lymphatic system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which is greater, immune or lymphatic system?

A

IMMUNE SYSTEM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Specific defenses of lymphocytes

A

part of the immune response

identify, attack, and develop immunity to a specific pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Non-specific defenses

A

block or attack any potential infectious organism. cannot distinguish one attack from another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Function of the lymphatic system

A

To produce, maintain, and distribute lymphocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Lymphocyte production

A

lymphocytes are produced in:

  • lymphoid tissues (tonsils)
  • lymphoid organs (spleen, thymus)
  • red bone marrow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Lymphocyte circulation

A

from blood to interstitial fluid thru capillaries

-returns to venous blood thru lymphatic vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Fluid circulation

A
  • from blood plasma to lymph and back to the venous system

- transports hormones, nutrients, and waste products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Difference between lymphatic and blood capillaries

A

lymphatic capillaries:

a. originate as pockets
b. large diameter
c. thinner wall
d. irregular shape in cross section
e. have lymphatic valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Lymph flow

A

from lymphatic capillaries to larger lymphatic vessels containing one way valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Lacteals

A

special lymphatic capillaries in small intestine, transport lipids from digestive tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

2 lymphatic ducts:

A

thoracic and right lymphatic duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Thoracic duct

A

a. drainage areas including the left upper and whole lower body
b. entering venous system in the left subclavian vein, the superior vena cava and right atrium
c. enlarged site is called cisterns chyli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Right lymphatic duct

A

a. drainage areas including right upper of the body

b. entering right subclavian vein, then superior vena cava and right atrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What percent of white blood cells are lymphocytes?

A

20-30% of WBC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

T cellls

A

80% thymus dependent cells

a. cytotoxic t cells: cell mediated immunity
b. helper t cells: stimulate t and b cells
c. suppressor t cells: inhibit t and b cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

B cells

A

(10-15%) bone marrow derived cells

  1. antibody (Ab) - mediated immunity (humoral immunity)
  2. differentiate into plasma cells to produce Ab
  3. ab also called immunoglobulins
  4. life span of b lymphocytes4-20 years
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

NK cells

A

5-10% natural killer cells

a. also called: large granular lymphocytes
b. act as immunological surveillance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Cytotoxic T Cells

A
  • attack cells infected by viruses

- produce cell mediated immunity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Memory T cells

A

formed in response to foreign substance

- remain in body to give immunity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Helper T cells

A

simulate function of t cells and b cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Suppressor t cells

A

inhibit function of t cells and b cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

regulatory t cells

A
  • are helper and suppressor t cells

- control sensitivity of immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is lymphopoeisis

A

lymphocyte production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q
  1. lymphocyte production in red bone marrow
A

Hemocytoblasts-> Lymphoid stem cells = NK cells and B cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q
  1. lymphocyte production in thymus (blood thymus barrier)
A

Lymphoid stem cells ————-> mature T cells

^ Thymic hormones (thymosins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Lymphocyte production

A

called lymphopoiesis, involves

  1. bone marrow
  2. thymus
  3. peripheral lymphoid tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Hemocytoblasts differentiate into 2 groups

A

group 1. lymphoid stem cells:
remains in bone marrow and develop with help of stromal cells
-produces b cells and natural killer cells
group 2 lymphoid stem cells
- migrates to thymus
-produces t cells in environment isolated by blood thymus barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Lymphoid tissues

A

(storage of lymphocytes) without fibrous capsule

  1. lymphoid nodules:
    a. respiratory tract
    b. digestive t- ex. payer’s patch, appendix (MALT)
    c. urinary tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Tonsils

A

a. pharyngeal tonsil (adenoid tonsil) single
b. palatine tonsils: a pair (R & L)
c. Lingual tonsils: a pair (R & L)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Lymphoid organs

A

covered with capsule
1 lymph nodes:
2. thymus:
3. Spleen:

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Mucosa Associated lymphoid tissues (MALT)

A
  • lymphoid tissues associated with the digestive, respiratory, urinary, and reproductive tracts
    ex. aggregated lymphoid nodules= peyer’s patch : cluster deep to intestinal epithelial lining
  • Appendix (vermiform appendix): contains a mass of fused lymphoid nodules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Lymph Nodes: Anatomy:

A

a. capsule= trabecular
b. afferent vessels
c. sub capsular sinus: d cells

Cortex:

a. outer cortex- D cells, b cells
b. germinal center- b cells
c. deep cortex- t cells

Medulla: b cells, plasma cells

Efferent vessel

Hilus

    • D cells: dendritic cells
  • function: initiating immune response
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Functions of lymph nodes

A

a. acting as a filter, purifying lymph before it reaches the venous system
b. providing an early warning system for immune responses (by d cells)
c. producing antibodies (by b cells and plasma cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Important lymph nodes

A

a. Cervical lymph node
b. axillary lymph node
c. inguinal lymph node (groin areas)

lymph nodes in gut and trachea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Lymphadenopathy

A

enlargement of lymph node (sign of infection, cancer or endocrine disorder)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Lymph nodes and cancer cells

A

lymph nodes serve as “way stations” for migrating cancer cells (bc lymphatic capillaries offer litter resistance to the passage of cancer cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Thymus anatomy

A

Location: in the mediastinum
weight: 40 g (2 year old)–> 12 g (50 year old)
capsule –> 2 thymic lobes
*many lobules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Thymus cortex

A

(immature t cells, reticular epithelial cells) producing thymosins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Thymus medulla

A

mature t cells, REC and more macrophages
-REC encircle thymus (hassall’s) corpuscles
Hassle’s corscuples: epithelial cells, unknown function

48
Q

Function of reticular epithelial cells (REC) or thymus

A

a. rec encircle the blood vessels and immature t cells, and maintain a blood thymus barrier in the cortex
b. rec secrete the thymic hormones (thymosins) for the maturation of t lymphocytes

49
Q

Thymus Medulla Area

A

does not have blood thymus barrier. mature t lymphocytes can enter the blood stream or lymphatic vessels here

50
Q

Reticular epithelial cells in the cortex of the thymus

A
  • surround immature lymphocytes in cortex
  • maintain blood thymus barrier
  • secrete thymic hormones
51
Q

Reticular epithelial cells in the medulla

A
  • form concentric layers known as the thymic corpuscles= hassalls corpuscles
  • the medulla has no blood thymus barrier
  • mature t cells can enter or leave bloodstream
52
Q

Where is the spleen located

A

the lateral border of the stomach, connected by gastro splenic ligament

53
Q

Red pulp of spleen

A

recycle of red blood cells

-contains macrophages (major cells), RBCs, and some lymphocytes

54
Q

White pulp of spleen

A

has a central artery
contains:
lymphocytes (major cells) in lymphoid nodules, and some macrophages AND dendritic cells (antigen presenting cells)

55
Q

Spleen: Blood Pathway:

A

Splenic artery— Hilus– white pulp

—cappillaries(sinusoids)–red pulp (macrophages engulf old RBCs)– small veins– hilus–splenic veins

56
Q

Spleen is the largest…

A

collection site of lymphoid tissues

57
Q

Functions of spleen

A

a. removing abnormal blood cells and fragments (red pulp)
b. storing iron (Fe+2) recycled from old RBC’s (red pulp)
c. initiating immune responses by t & B cells (white pulp)

58
Q

Innate (non specific) defenses

A
  • always work the same way
  • against any type of invading agent
  • nonspecific resistance
59
Q

Adaptive (specific) disease

A
  • protect against specific pathogens
  • depend on activities of lymphocytes
  • specific resistance (immunity)
    a. develops after exposure to environmental hazards
60
Q

Nonspecific defenses (7)

A
  1. physical barriers
  2. phagocytes
  3. immunological surveillance (Nk cells(
    4 interferons
    5 complement
    6 inflammatory response
    7 fever
61
Q

Non specific defenses– physical barriers

A

skin, hair, epithelium, mucus,, acids

62
Q

non specific defenses: phagocytes:

A

microphages:from neutrophils and eosinophils
macrophages: from monocytes (reticulo-endothelial system)
a. fixed macrophages: (histiocytes) in bone marrow, connective tissue
- microglia: in CNS
- kupffer cells: in liver sinusoids
free macrophages: wandering macrophages. ex. alveolar macrophages-> dust cells

63
Q

chemotaxis

A

WBCs or macrophages are attracted to the infected sites by chemicals released from other defense cells

64
Q

Cells in the CNS

A
  1. neurons:
  2. neuroglial cells: (90%)
    - astrocytes
    - microglia
    - ependymal cells
    - oligodendrocytes

** No lymphatic capillary system in the CNS

65
Q

Immunological surveillance (by NK cells)

A

a. against virus and cancer cells
b. NK cells release proteins (perforins) to lysis membranes of pathogenic cells
c. immunological escapes: NK cells have no effect for some cancer cells

66
Q

Interferons

A

a. against viruses
b. released by lymphocytes, macrophages, and virus infected cells
c. one of the cytokines (chemicals released by tissue cells to response to local infections.) they can act as paracrine or endocrine hormones

67
Q

3 types of interferons:

A
1 alpha 
- produced by leukocytes and virus infected cells
- stimulate NK cells
2. beta
-secreted by fibrocytes
-slow inflammation
3 gamma
- secreted by t cells and NK cells
-stimulate macrophage activity
68
Q

Complement (C) proteins

A

a.against bacteria
b. stimulate inflammation: (+) histamine release by mast cells
c/ attract phagocytes
d. enhance phagocytes
e. produced by liver PEOPLE WITH LIVER DISEASE HAVE LESS COMPLEMENT PROTEINS

69
Q

Inflammation (inflammatory response)

A
  • by mast cells (mobile connective tissue cells that release histamine and heparin)
  • cardinal signs and symptoms: swelling, redness, heat and pain
70
Q

Fever

A
  • temp >37.2 C or 99 F
    -temperature regulation center: (pre optic area) PO of hypothalamus
  • Pyrogen (& interleukin-1 = IL-1): a chemical released by macrophages to increase temperature
    -The benefit of fever (if it is within a healthy limit):
    a. Inhibit growth of bacteria or virus
    b. (+) body metabolism
    c. (+) mobilization of tissue defenses:
    WBCs move faster
    d. (+) tissue repair.
71
Q

Specific defenses (Immune Response):

A

Innate immune and acquired immune

72
Q

innate immune

A

present at birth

73
Q

Acquired immune

A

Active Im: develops after exposure to antigen (Ag)
a. Induced A. Im: (ex. Vaccination)
b. Natural acquired A. Im:
Passive Im: produced by transfer of Ab from another source
a. Induced P. Im: (ex. injecting Ab to treat patient)
b. Natural acquired P. Im:

74
Q

Properties of immunity (4)

A
  1. Specificity
  2. Versatility: abilities to face different Ags due to
    diversity of lymphocytes
  3. Memory
  4. Tolerance: not response to some Ags
75
Q

Innate (Nonspecific) Defenses

A

Always work the same way
Against any type of invading agent
Nonspecific resistance

76
Q

Adaptive (Specific) Defenses

A

Protect against specific pathogens
Depend on activities of lymphocytes
Specific resistance (immunity)
Develops after exposure to environmental hazards

77
Q

Cell-mediated Immunity (by T cells):

A
  1. Ag presentation:a. By the presence of Ag-glycoprotein from foreign cells
    b. By the membrane proteins (MHC: major histocompatibility
    complex) of infected cells: MHC Class I
    c. By the membrane proteins in Ag-presenting cells:
    MHC Class II.

(ps): Ag presenting cells (APCs):

	a. Free & fixed macrophages: in connective tissues, 
		Kupffer cells (in liver), microglia (in CNS).
	b. Langerhans cells of skin, dendritic cells of lymph nodes 
		& spleen.
  1. Ag recognition:
78
Q

MHC Proteins

A

The membrane glycoproteins that bind to antigens
Genetically coded in chromosome 6
The major histocompatibility complex (MHC), our own cell membrane markers.
Differs among individuals

79
Q

Class I (= MHC-I) vs Class II (= MHC-II):

A
Class I (= MHC-I):
* Found in membranes of all nucleated cells 

Class II (= MHC-II):

  • Found in membranes of antigen-presenting cells (APCs)
  • Found in lymphocytes
80
Q

Ag recognition:

A

T cells & macrophages have cell membrane marker:
CD (closter of differentiation).
A. Tc, Ts: CD8—Class I MHC:

	a. Release perforin (ATTACKS CELL MEMBRANE)
	b. Release lymphotoxin
	c. Release cytokines--- apoptosis (cell death) changes DNA and puts it into cell death

d. Produce memory Tc cells

B. TH:  CD4 ----- Class II MHC:

	a. Produce memory T-helper cells
	b. Bind & activate B cells
81
Q

CD Markers

A
  • Also called cluster of differentiation markers
    In T cell membranes
    Molecular mechanism of antigen recognition
    More than 70 types CD markers
82
Q
  • CD3 Receptor Complex
A

Found in all T cells

83
Q
  • Two Important CD Markers
A
  1. CD8 Markers
    Found on cytotoxic T cells and suppressor T cells
    Respond to antigens on Class I MHC proteins
  2. CD4 Markers
    Found on helper T cells
    Respond to antigens on Class II MHC proteins
84
Q

Antibody-mediated Immunity (by B cells)

A
  1. B cell sensitization:
    a. By MHC II on B-cell membrane
    b. By binding with activated T-helper cell
  2. B cell activation:
    a. Produce memory B cells
    b. B cells become plasma cells
    c. Plasma cells produce Abs
85
Q

Hapten (Partial Antigens)

A

Must attach to a carrier molecule to act as a complete antigen
Dangers of Haptens
Antibodies produced will attack both hapten and carrier molecule
If carrier is “normal”:
Antibody attacks normal cells
For example, penicillin allergy

86
Q

IgG:

A

IgG is the largest and most diverse class of antibodies
80 percent of all antibodies
IgG antibodies are responsible for resistance against many viruses, bacteria, and bacterial toxins
Can cross the placenta, and maternal IgG provides passive immunity to fetus during embryological development
Anti-Rh antibodies produced by Rh-negative mothers are also IgG antibodies and produce hemolytic disease of the newborn

87
Q

IgE

A

attaches as an individual molecule to the exposed surfaces of basophils and mast cells
When an antigen is bound by IgE molecules:
The cell is stimulated to release histamine and other chemicals that accelerate inflammation in the immediate area
IgE is also important in the allergic response

88
Q

IgD:

A

is an individual molecule on the surfaces of B cells, where it can bind antigens in the extracellular fluid
Binding can play a role in the sensitization of the B cell involved.

89
Q

IgM:

A

the first class of antibody secreted after an antigen is encountered
IgM concentration declines as IgG production accelerates
Plasma cells secrete individual IgM molecules, but it polymerizes and circulates as a five-antibody starburst
The anti-A and anti-B antibodies responsible for the agglutination of incompatible blood types are IgM antibodies
IgM antibodies may also attack bacteria that are insensitive to IgG

90
Q

IgA:

A

found primarily in glandular secretions such as mucus, tears, saliva, and semen
Attack pathogens before they gain access to internal tissues
IgA antibodies circulate in blood as individual molecules or in pairs
Epithelial cells absorb them from blood and attach a secretory piece, which confers solubility, before secreting IgA molecules onto the epithelial surface

91
Q

Primary and Secondary Responses to Antigen Exposure

A

Occur in both cell-mediated and antibody-mediated immunity

First exposure (primary response)
IgM is weak. Take 2 weeks for IgG peak
Next exposure (secondary response)
IgG rises very high & quickly. Extends longer time.
IgM is also quicker and slightly extended
Memory cells already primed

92
Q

Four Categories of Allergic Reactions

A

1 Immediate hypersensitivity: Type I

2 Cytotoxic reactions: Type II (ex. Blood typing)
3 Immune complex disorders: Type III
4 Delayed hypersensitivity :Type IV
(ex.poison ivy)

93
Q

Type I Allergy (immediate hypersensitivity)

A

A rapid and severe response to the presence of an antigen
Includes allergic rhinitis (environmental allergies)
Production of large quantities of IgE antibodies
Massive inflammation of affected tissues
Allergens in bloodstream may cause anaphylaxis

94
Q

Anaphylaxis

A
Can be fatal
* Affects cells throughout body
* Changes capillary permeability
Produces swelling (hives) on skin
* Smooth muscles of respiratory system contract
Make breathing difficult
* Peripheral vasodilatation
Can cause circulatory collapse 
     (= anaphylactic shock)
95
Q

Seven Functions of Ag–Ab Complexes

A
Neutralization of antigen binding sites
Precipitation and agglutination 
		- formation of immune complex
3. Activation of complement
4. Attraction of phagocytes
5. Opsonization increasing phagocyte efficiency
6. Stimulation of inflammation
7. Prevention of bacterial and viral adhesion
96
Q

Combined Responses to Bacterial Infection

A
Neutrophils and NK cells begin killing bacteria
Cytokines draw phagocytes to area
Antigen presentation activates:
Helper T cells
Cytotoxic T cells
B cells activate and differentiate
Plasma cells increase antibody levels
97
Q

Combined Responses to Viral Infection

A

Similar to bacterial infection

But cytotoxic T cells and NK cells are activated by contact with virus-infected cells

98
Q

Cytokines

A

Chemical messengers involved in cellular immunity produced primarily by macrophages and lymphocytes.
Hormones and paracrine-like glycoproteins: (ex.)
Interferons
Interleukins
Tumor necrosis factors (TNFs)
Colony-stimulating factors (CSFs)

99
Q

Immune System Development in Fetus

A

Fetus can produce immune response
Fetal thymus cells migrate to tissues that form T cells
Liver and bone marrow produce B cells
Four month fetus produces IgM antibodies

100
Q

Before Birth

A

Maternal IgG antibodies
Pass through placenta
Provide passive immunity to fetus
GIVE THE BABY IGA IN THE FIRST TWO WEEKS. AT LEAST 2 WEEKS.

101
Q

After Birth

A

Mother’s milk provides IgA antibodies

102
Q

Stress and the Immune Response

A
Glucocorticoids
Secreted to limit immune response 
Long-term secretion (chronic stress)
Inhibits immune response
Lowers resistance to disease
103
Q

Immune system and age

A

Increasing vulnerability to infections and cancer

104
Q

Four Effects of Aging

A

1Thymic hormone production is greatly reduced
2 T cells become less responsive to antigens
3 Fewer T cells & reducing responsiveness of B cells
4 Immune surveillance against tumor cells declines

105
Q

Effects of Glucocorticoids

A

Depression of the inflammatory response
Reduction in abundance and activity of phagocytes
Inhibition of interleukin secretion

106
Q

Tumor Necrosis Factors (TNFs)

A

TNFs slow the growth of a tumor and kill sensitive tumor cells
Activated macrophages secrete one type of TNF and carry the molecules in their plasma membranes
Cytotoxic T cells produce a different type of TNF
In addition to their effects on tumor cells:
TNFs stimulate granular leukocyte production, promote eosinophil activity, cause fever, and increase T cell sensitivity to interleukins

107
Q

Phagocyte-Activating Chemicals

A

Several cytokines coordinate immune defenses by adjusting the activities of phagocytic cells
Include factors that attract free macrophages and microphages and prevent their premature departure from the site of an injury

108
Q

Colony-Stimulating Factors

A

Factors are produced by active T cells, cells of the monocyte-macrophage group, endothelial cells, and fibrocytes
CSFs stimulate the production of blood cells in red bone marrow and lymphocytes in lymphoid tissues and organs

109
Q

Immune Disorders

3

A
  1. Autoimmune disorders
  2. Immunodeficiency disease
  3. Allergies
110
Q

Autoimmune Disorders

A

A malfunction of system that recognizes and ignores “normal” antigens

Activated B cells make autoantibodies against body cells
Examples:
Thyroiditis
Rheumatoid arthritis
Insulin-dependent diabetes mellitus (IDDM)

111
Q

Immunodeficiency Diseases

A

Result from:
Problems with embryological development of lymphoid tissues
Can result in severe combined immunodeficiency disease (SCID)
Viral infections such as HIV
Can result in AIDS
Immunosuppressive drugs or radiation treatments
Can lead to complete immunological failure

112
Q

HIV (human immunodeficiency viruses):

A

A. Attack T-helper cells (with CD4 coreceptors) and wipe
out immune system.
a. Release more viruses after an infected cell is dead.
b. cause infected cell releasing a chemical to block
other T cells to come.
c. inhibit MHC gene expression (avoiding be recognized

B. HIV are transferred by any internal body fluids.
		(200 millions/ a size of period)

C. Treatments:

	a. AZT: inh. RNADNA (reverse transcription)
	b. Protease inhibitor: inhibits viral assembly
	c. Vaccine? Difficult due to Ag changes
113
Q

Allergies

A

Inappropriate or excessive immune responses to antigens

114
Q

allergens

A

Antigens that trigger allergic reactions

115
Q

Allergy (or hypersensitivity):

A

Immediate hyper-sensitivity:
a. Produce symptom within second or minutes
b. mediated by B cells, Ag-Ab reaction
c. Produce IgE
d. secondary exposure to the Ag causing mast cells
to release histamine
e. ex. Food, bee stings, pollens, hay fever
f. Anaphylactive shock: decrease of blood pressure
acutely (ex. Penicillin allergy)
2. Delayed hypersensitivity:
a. Mediated by T cells (response hours later)
b. Ex. Poison ivy causing dermatitis
c. Secretion of lymphokines
d. Treatment: corticosteroids (not anti-histamines)