Flashcards in The Immune System Deck (35)
What is the immune system?
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
What are the major components of the immune system
Innate Immune System
Adaptive Immune System
What are the physical barriers of the integumentary system?
Describe the skin barrier
acidic environment (pH 3-5)
inhibits the growth of microbes
Describe the mucous membrane
bacteria flora compete with foreign microbes for nutrients
Describe the temperature barrier
body temperature inhibits the growth of some organisms
fever response, signals to activate
Describe the stomach barrier
very acidic (pH 1.5-3.5)
hard for pathogens to live in
Describe the tears barrier
mostly lysozyme to destroy cellular particles
Describe the sweat barrier
contains chemicals which kills pathogens
Describe the saliva barrier
also contains enzymes
What is the innate and adaptive immune system?
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
What is a granulyte and what are its types
part of the myeloid lineage
Describe the Neutrophil
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
What are dendritic cells?
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
What are eosinophils?
contain many granulocytes that stain pink in acid
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
What are monocytes?
comprise 5-10% of white blood cells
immune system swarmers
can turn into macrophages
What are macrophages?
high degree of migration
home to sites of inflammation
exhibit phagocytic activity
What are basophils?
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
What are mast cells?
contain many granules
present in most tissues
function to amplify inflammatory responses
What is a lymphocyte?
Three major types
T-lymphocytes play a role in cell mediated immunity
B-lymphocytes are precursors of plasma cells
natural killer and killer cells
What is the innate immune system?
front line of internal defense
non immunologic memory
granulocytes play a large role
Describe the inflammatory response
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
What is the purpose of Histamine?
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
What are NK cells?
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
What is the complement inflammatory response?
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
What is the adaptive immune system?
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)
What are the four attributes of the immune system?
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
What are T-cells?
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)
What are T-inducer cells?
induce other T-cells to become suppressor T cells
act on other T-cells to single transcription