The Immune System

Question 1

What is the immune system?

Answer 1

the biological structures and processes within an organism that protect against disease by identifying and killing pathogens
detects everything from viruses and bacteria to parasitic worms and graft tissue

Question 2

What are the major components of the immune system

Answer 2

Integumentary System
Innate Immune System
Adaptive Immune System

Question 3

What are the physical barriers of the integumentary system?

Answer 3

Skin
Mucous Membranes
Temperature
Stomach
Tears
Sweat
Saliva

Question 4

Describe the skin barrier

Answer 4

mechanical barrier
acidic environment (pH 3-5)
inhibits the growth of microbes

Question 5

Describe the mucous membrane

Answer 5

bacteria flora compete with foreign microbes for nutrients

mucous movement/expulsion

Question 6

Describe the temperature barrier

Answer 6

body temperature inhibits the growth of some organisms

fever response, signals to activate

Question 7

Describe the stomach barrier

Answer 7

very acidic (pH 1.5-3.5)
hard for pathogens to live in

Question 8

Describe the tears barrier

Answer 8

contains enzymes

mostly lysozyme to destroy cellular particles

Question 9

Describe the sweat barrier

Answer 9

contains chemicals which kills pathogens

Question 10

Describe the saliva barrier

Answer 10

also contains enzymes

Question 11

What is the innate and adaptive immune system?

Answer 11

internal cellular response to pathogens
cells which are distributed throughout the body in the blood, lymph, and epithelia
Major organs are spleen, thymus, tonsils, and bone marrow
originate from bone marrow
two major lineages: Myeloid and Lymphoid

Question 12

What is a granulyte and what are its types

Answer 12

part of the myeloid lineage
Basophil
Neutrophil
Eosinophil

Question 13

Describe the Neutrophil

Answer 13

comprise the majority of white blood cells
polymorphonuclear leucocytes (multi lobed nuclei)
7 million released per minute from bone marrow
Function : phagocytosis and intracellular digestion of particulate antigens
produce reactive oxygen intermediates with anti microbial potential

Question 14

What are dendritic cells?

Answer 14

the branching cell
antigen presenting cells, critical for the adaptive immune system
When mature, their cytoplasm extends into dendrite like structures
the scouts or messenger of the immune system

Question 15

What are eosinophils?

Answer 15

contain many granulocytes that stain pink in acid
Bilobed nuclei
make up 2-5% of white blood cells
they secrete their granule contents for extracellular digestion of infectious pathogens which are too large to be engulfed
all secrete proteins which inhibit inflammation

Question 16

What are monocytes?

Answer 16

comprise 5-10% of white blood cells
immune system swarmers
can turn into macrophages

Question 17

What are macrophages?

Answer 17

high degree of migration
home to sites of inflammation
exhibit phagocytic activity

Question 18

What are basophils?

Answer 18

stain with basic dyes (dark purple in H&E)
play role in the inflammatory response
contain heparin which prevents blood from clotting two quickly
contain histamine which promotes blood flow to tissue

Question 19

What are mast cells?

Answer 19

contain many granules
present in most tissues
function to amplify inflammatory responses

Question 20

What is a lymphocyte?

Answer 20

Three major types
T-lymphocytes play a role in cell mediated immunity
B-lymphocytes are precursors of plasma cells
natural killer and killer cells

Question 21

What is the innate immune system?

Answer 21

front line of internal defense
non-specific
non immunologic memory
immediate response
granulocytes play a large role

Question 22

Describe the inflammatory response

Answer 22

a non-specific response triggered by injury of penetration of bacteria
two main players, histamine and complement system
prevents the spread of damaging agents to nearby tissues
redness, heat, swelling, and pain to a localized area

Question 23

What is the purpose of Histamine?

Answer 23

dilates local blood vessels
increases capillary permeability that results in redness, heat, and swelling
Heat is unfavorable to microorganisms
helps to mobilize white blood cells (monocytes)
raises the metallic rate of surrounding cells

Question 24

What are NK cells?

Answer 24

do not express antigen specify receptors
no adaptive memory
part of innate system
main function is to kill infected cells and tumor cells by apoptosis induction
kills cells with reduced expression of MHC class I molecules
can result from viral infection or migrant transformation

Question 25

What is the complement inflammatory response?

Answer 25

A chemotaxis agent (chemical movement) that recruits white blood cells to the area (like a fly trap)
1: Involved in and amplify the inflammatory response
2: They can trigger histamine release
3: Attracts phagocytes (macrophages and neutrophils)
4: Can form a membrane attack complex that produces holes in the surface of some bacteria and viruses
Fluid and salts then enter the bacteria cell or virus to the point that it bursts

Question 26

What is the adaptive immune system?

Answer 26

A slower response that requires both the B and T lymphocytes that’s produced in bone marrow (T-cells in thymus and B-cells in the bone marrow)

Question 27

What are the four attributes of the immune system?

Answer 27

1: Antibody specificity - distinguishes minute differences in molecular structure to determine non self antigens (targets specific molecules)
2: Diversity - can produce a huge diverse set of recognition molecules which allows us to recognize billions of antigens and their shapes
3: Memory - once it has responded to an antigen the system maintains a memory of that antigen for a finite time
4: Self-nonself recognition - the system typically responds only to foreign molecules

Question 28

What are T-cells?

Answer 28

do not produce antibodies, they attack foreign antigens directly
exert effects on other cells to regulate immune cell activity and to directly kill infected/malignant cells
They gave surface antigen receptors, but do not secrete an equivalent form
They cannot recognize antigens in their native forms (only when present on the surface of antigen-presenting cells)

Question 29

What are T-inducer cells?

Answer 29

induce other T-cells to become suppressor T cells

act on other T-cells to single transcription

Question 30

What are T-suppressor cells?

Answer 30

the antigen sponge
suppressor effector T cells bind antigens and release factors that inactivate T-helper cells
They suppress hypersensitivity reactions and prevent proliferation and antibody secretion by antigen-binding B cells

Question 31

What are Helper T cells?

Answer 31

the stimulate the T cells to attack by bridging to the antigen with the MHC molecules and accessory protein
reside in lymph nodes
rely on antigen presenting cells - dendritic cells
They activate B cells and killer T cells
Helper T cells are activated when a macrophage or dendrite cell has phagocytize an invader, travels to the nearest lymph node and presents information about the captured pathogen
Phagocyte displays an antigen fragment from the invader on its own surface (antigen presentation)
When the receptor of a helper T cell recognizes the antigen the T cell is activated
Helper T cell then divides and produces proteins that activate B and T cells as well as other immune cells

Question 32

What are Cytotoxic T cells?

Answer 32

They kill infected cells that bear foreign antigens on contact

Question 33

What is the Major Histocompatibility Complex?

Answer 33

MHC, also called human leukocyte antigens (HLA)
All cells except mature RBS are marked with histocompatibility antigens on the membrane surface
Class I: produced by all cells except RBCs
Class II: produced only by antigen-presenting cells and B-cells
only appear on cell membrane when cells in processing antigens
activate T cells
Helper T cells react with MHCII

Question 34

What are B cells?

Answer 34

They give rise to antibodies that are shaped like antigen receptors and are capable of combining with and neutralizing antigens
They secrete soluble recognition molecules called antibodies which specifically bind to an antigen recognized by that B cell
only produces antibodies when it has been activated by a binding antigen (with help from T cells)
Undergo multiple divisions and some of the resulting cells differentiate into antibody-secreting cells (plasma cells and memory B cells)

Question 35

What is a CD system?

Answer 35

cluster of differentiation
helps to identify intermediate differentiation steps
and how active a cell is or is not
Ex: T-cells: CD4+ or CD8+ where the + says it has a marker or - if it does not