Immune System Flashcards
external defenses are specific or non specific?
all non specific
external defenses
skin- water proof layer dead cells
linings of body tubes/cavities
neutral/beneficial bacteria population
examples of linings of body tubes/cavities
1) sticky mucus w/ lysozyme enzymes
2) ciliated cells in resp. tract
3) stomach acid & bile salts
4) urine & vaginal low pH
internal defense types
innate immunity
acquired/adaptive immunity
innate immunity
present at birth, always present, all animals, non-specific
aquired/adaptive immunity
activated by microbes/antigens (very specific)
a) Require self-recognition (membrane proteins)
b) only present in Vertebrates
Antigens
any foreign molecule recognized by immune system
antigens examples
1) bacteria membrane proteins
2) parts of virus protein coat
3) oligosaccharides on transplanted cells
Phagocytes
cell that does phagocytosis (ingestion)
examples of Phagocytes
- endocytosis to take in and digest organic materials
- in immune system take in microbes
(virus/bacteria) & digest them
MHC =
major histocompatibility molecules
major histocompatibility molecules
cell surface proteins display antigens
two types
warning flags to attract immune system
Class one MHC
display foreign peptides synthesized within the cell (cancer/virus) cell made it ITSELF and shouldnt have
found on most body cells
Class two MHC
display peptides broken off of microbes during phagocytosis
found on phagocytic cells & B cells
Helper–T cells
Type of white blood cell
Blood Cells – all start in
bone marrow
Leukocytes =
White Blood Cells
Lymphocytes phagocytes
and Erythrocytes
Lymphocytes
B cells and T cells
B cells mature in
bone marrow
T cells mature in
thymus gland
Erythrocytes=
red blood cells
red blood cells
1) anucleate in mammals
2) hemoglobin carries O2 and some CO2
3) flexible biconcave oval
4) form in bone marrow
Phagocytic cells (2 examples)
macrophages – largest
dendritic cells – activate acquired immunity
dendritic cells
a) digest pathogen into pieces
b) bind pathogen pieces to MHC receptors*
c) display pathogen on cell membrane
d) attract helper T cells*
e) helper T cells activate acquired imm. resp.
Natural Killer Cells
NK cells vertebrate innate defense.
- Attack virus infected cells and cancer cells
- detects changes in cell membrane
- Produce signal molecules that cause apoptosis
are NK cells MHC molecule receptors
NOT MHC molecule receptors…just detects changes in cell membrane
Antimicrobial Proteins
warns neighbors of virus around
interferon ά and β
complement system = 30 serum proteins
interferon ά and β
secreted by virus-infected cells
help neighboring cells inhibit viral reproduction
complement system
microbe presence activates complement proteins
cascade of chem rxns lead to microbe lysis
plays a role in inflammation
also activated by acquired response
inflammation process
Mast cells release histamine signal mol.
Histamine signals capillaries to
dilate and produce signal molecules to attract phagocytes/macrophages which secrete cytokines to promote blood flow
Mast cells release histamine signal mol.
due to
Allergen, antigen or injury
dialation in inflammation lets out more
clotting elements (block spread of microbes)
anti-microbial proteins (complement system)
and Phagocytes
Histamines
released by mast cells
trigger capillaries to dilate
Chemokines
released by capillaries
attract phagocytes
Cytokines
when released by macrophages increase blood flow when released by helper T activate acquired immune resp. cytokines activate acquired immune system signal B-cells and cytotoxic-T cells
Systemic Response
Widespread response
Increased WBC production
Fever
Septic shock
fever facilitates
phagocytosis
septic shock
bacterial infection causes high fever low blood pressure and may cause death
aquired/adaptive immunity
Humoral Response
or Cell Mediated Response
Cell Mediated Response
Cytotoxic T cells defends against:
infected cells
Cancer cells
Transplanted cells
Humoral Response
B cells make antibodies in fluid (humor)
antibodies
Proteins secreted by differentiated B-cells
(plasma cells)
Bind to specific antigen
antibodies also called
Also called Immunoglobulins (Ig)
humoral response process
B cell receptor binds to an antigen on microbe, pollen or transplanted cell
- B cell takes in antigen and presents it on MHC II surface protein to attract helper T cells
- Helper T binds to MHC-antigen complex and begins secreting cytokines
- cytokines induce mitosis in B cell to produce
a. plasma cells
b. memory B-cells
cytokines induce mitosis in B cell to produce
plasma cells
memory B-cells
Plasma cells
make antibodies specific to the antigen that their parent B-cell bound
what do antibodies do?
- bind & clump viruses/bacteria
- precipitate antigens dissolved in fluid
- activate complement proteins
Memory B-cells
stay in blood stream ready to become activated in secondary immune response.
how does the first immune response compare to secondary response
the second immune response is larger (way more antibodies) and faster
Cell Mediated Response fights `
cancer, infected cells, transplant cells
Cell Mediated Response process
Class I MHC molecule displays antigens
that are synthesized inside affected cell
2. Cytotoxic Tcells bind to MHC-antigen complex
3. Binding makes cytotoxic Tcell secrete:
a. perforin
(protein, makes holes in membrane)
b. enzymes to digest the cell
c. signals to cause apoptosis
in cell mediated response process, binding to cytotoxic cells makes t cell secrete
perforin (protein, makes holes in membrane)
enzymes to digest the cell
and signals to cause apoptosis
Helper T cells Activate by
binding C-II MHC-antigen complex
on dendritic cells, macrophages, or B-cells
helper t cells make cytokines to stimulate
cytotoxic T cells to become active
B cells to begin clonal selection…..
mitosis to produce plasma & memory cells
trigger helper t to start dividing
Helper T clonal selection
Activated helper T does mitosis
1 clone divides to make many activated helper T cells
The other divides to make memory helper T cells
Lymphocyte receptor diversity
millions of different b cells and t cells
When leukocytes differentiate into lymphocytes
Recombinase enzymes link 1 V gene segment to 1 J gene segment which makes tons of different receptors
all receptors on that cell the sam
Autoimmune disease
Failure to remove self-reactive cells
lymphocyte receptors bind to bodies own cells
help t cells process
Receptors bind to (antigens) displayed by MHC molecules
secretes signal molecules called cytokines which activate aquired immune response
aquired immunity cells
b and t cells
what are specific
aquired immune response
B and T cells
antibodies
whats not specific
innate immune response
phagocytes- dendritic cells
natural killer cells
antimicrobial proteins
