The Immune System

pathogens

microorganisms that cause disease

things that our immune systems protects against

viruses

bacteria

1) exposure

in the presence of pathogens

2) colonization

pathogen in or on you

3) infection

invasion and growth of pathogen

4) disease

pathology-tissue damage

immune response and recovery

immunse systems deploying WBCs and tissues to recover

immunity

immune system is familiar and has antibodies to defend in the future

immune system cells

lymphocytes, antigen presenting cells, inflammatory cells

immune system tissues

central: thymus, bone marros

peripheral: lymphatic system, lymoh nodules, spleen, circulation, lymph nodes

innate immune response

parts/structures of your immune system that youre born with

specific immune response

chacteristsics of your immune system that you develop

pleuro potential

having many possibilities to become something

ex: stem cells have pleuropotential

natural defense factors

skin, mucous membranes, ciliated epithelium, gastric juice, lactic acid, normal flora

non-specific immunity characteristics

endocytosis

inflammation

natural killer cells

pattern recognition receptors

endocytosis characteristics

phagocytosis, pinocytosis, receptor-mediates endocytosis

phagocytosis

endocytosis definition

cell eating or the engulfment of particulate or soluble matter by cell

diapedesis

the process where white blood cells (leukocytes) squeeze through the walls of intact blood vessels to move into surrounding tissues

inflammation

inflitration of WBCs into tissue

natural killer cells

cell cytotoxicity

what pattern recognition receptors do?

Bind to unique microbial molecules to trigger ingestion by phagocytes

non specific immunity differentiates

between self and non-self

chacteristics of specific immunity

humoral immunity B-cells

cell medicated immunity T-cells

non specific immunity is 

present at birth

specific immunity is

acquired and adaptive overtime

Humoral Immunitry B-cells

primarily by producing antibodies (proteins) that target and neutralize extracellular pathogens; indirect

Cell Mediated immunity T-cell

directly

natural killer cells

detect and eliminate infected or cancerous cells, thus protecting the body from various diseases

pattern recognition

Recognize structurally conserved molecules on pathogens – molecules pathogens have but your cells do not

• Allows phagocytic cells to identify and kill

which cell mediaties Specific Immune Response

lymphocytes

-little cytoplasms and large nucleus

what is activley acquired immune response?

Exposure of host to Antigen (Ag)

Natural – direct contact with antigen – pathogen

what is an artificially acquired immune response?

immunization through introduction of antigen

Immunization → Booster → Immunity

what is herd immunity?

when a large part of the population in an area is immune to a specific disease. Thus, the pathogen is more likely to contact an immune individual than a susceptible one. The infection does not spread

how can you produce herd immunity?

through both actively acquired and artificially acquired immunity

-activley immunity can be costly

how long does acquired immunity develop?

over your lifetime

what is an antigen?

A foreign substance that has the capacity to turn on (elicit not illicit)

the specific immune response (SIR) and then react with the products of the SIR.

what is specificity?

response directed against specific foreign material

what is adaptiveness

ability to respond to any foreign material

what is discrimination?

between self and non-self

what is immune response memory?

learned behavior – recall of previous exposures

where do lymphocytes mature?

central lymphoid organs: thymus and bursal equivalent tissue

what is a central lymohoid organ?

Organ where antigen (foreign material) independent

maturation / differentiation takes place

thymus

Maturation of lymphocytes into T-cells (first letter of thymus)

that function in Cell Mediated Immune Responses and Immune Regulation

bursal equivalent tissue

Maturation of lymphocytes into B-cells (first letter

in Bone) that function in Humoral Immunity (Antibody)

where is the thymus found?

below the thyroid and continues into the thoracic cavity forming a

sheath over the heart

what is the general shape of the thymus?

bi-lobed; 15 to 20 gm at birth, 40 gm at puberty, after

puberty it undergoes involution / atrophy

and decreases in size and function

how is a mature t-cell defined?

defined by having T-cell receptor (TCR) for Antigen

what does a Th0 become?

it become either a Th1 or a Th2 depending on antigen

what does Th 1 do?

Promotes cellular immunity mainly through stimulating Tctl

(cytotoxic lymphocytes)

what does Th2 do?

Promotes humoral immunity mainly by stimulating

B-cells to produce antibody (Ab)

how are B-cells defined?

by having Immunoglobulin /antibody surface receptor

→ immunoglobulin is used to bind to antigen

what is a peripheral lymphoid organ?

Lymph Nodules

Lymph Nodes

Spleen

what do peripheral lymphoid organs do?

Contains mature T- and B-cells

• Site where the specific immune

response is generated

• Where T and B-cells interact with

antigen – foreign material

• Widely distributed throughout the body

to cover all Ag exposures

Lymph Nodules allow

immune cells/tissues to be in direct

contact with the environment.

Peyer’s Patches

= unencapsulated lymphatic tissue in the

small intestines

what is BALT?

Bronchial Associated Lymphoid Tissue

what is GALT?

Gut Associated Lymphoid Tissue

what is UGALT?

Urogenital Associated Tissue

the lymphatic system is a?

Network of vessels

• Parallel the circulatory

system

what does the lymphatic system do?

Designed to collect fluid from tissues that leaks out of capillary beds

• Returns fluid to the circulation

It has evolved to be part of the immune system to collect soluble antigens in tissues

lymph nodes collect?

antigen from tissues and bring it to lymph nodes

lymph nodes contain?

T and B-cells – Cortex and Paracortical areas

the spleen stores

RBCs, highly vascular

what does the spleen do for the immune system?

filters the blood, traps pathogens and [resents to immune cells

spleen primary follicle

A resting B-cell zone that has not yet been activated by antigen exposure

spleen germinal center

A site within the spleen (and lymph nodes) where B-cells proliferate, mutate, and differentiate after encountering an antigen

slpeen perivascular sheath

A T-cell–dominated region surrounding central arteries, part of the white pulp.

What is the paracortical area of a lymphoid organ?

a T-cell–rich zone, especially active during immune responses, located between follicles and blood vessels

Where does the t-cell mature?

the thymus and shrinks with age

where do b cells mature?

bone marrow (bursa in birds)

what are secondary lymphoid organs?

Lymph nodes, spleen, lymph nodules (BALT, GALT, UGALT)

what does the M-cell do?

Presents antigens to B and T cells in mucosal tissues

what makes a good antigen?

Large size, foreignness, complexity (epitopes), digestibility

what is the role of APCs?

Present antigens to Th0 cells → Th2 helps B cells → B cells become plasma and memory cells

what are teh functions of antibodies?

Opsonization, Agglutination, Toxin neutralization, Bacterial/viral neutralization

which antibody crosses the placenta?

IgG

Which antibody is found in breast milk?

IgA