Introduction Flashcards
do all animals have immune systems
yes, even primitive ones like sponges have phagocytes
phagocytes
innate- look foreigners and engulf
only after shark species had evolved did
B and T cells start playing a role in immunity
snails are
major vectors of human parasites
humans have
highly diverse TLRs (TLR expansion)
primitive fish
have components which look like antibodies
as the immune system gets more complex
huge expansion and variability of T and B cells
humans have good
adaptive memory due to memory cells
Mab 5C04 (4)
- grows quickly
- produces lots of antibodies
- v robust
- do not need extra supplementation to grow well
adaptive immunity has become
increasingly efficient in vertebrates
how many cells in immune system
10^12
how many cell in brain
10^11
number of cell types in immune system
> 10
how many cells in brain
2
how man connections in immune system
infinite
why is the immune system described as being in a constant arms race with pathogens
as pathogens adapt and changes, so does the immune system
immunity become much more sophisticated
when the thymus and spleen had developed in the body
thymus
Main organ of lymphatic system.
- key to adaptive immunity
- nursury for maturation of T-lymphocytes
T-lymphocytes
mature in thymus then leave and are transported via blood vessels to the lymph nodes and spleen.
–> cell-mediated immunity- activation of certain immune cells to fight infection
Lymphatic organs
thymus and spleen
spleen
Largest organ or lymphatic system.
- Its primary function is to filter blood of damaged cells, cellular debris, and pathogens
- maturation of lymphocytes
- The spleen also contains efferent lymphatic vessels, which transport lymph away from the spleen and toward lymph nodes.
dendritic cells
relay innate immunity to the adaptive immune system
GALT
gut-assosicated lymphoid tissue
what is GALT?
is a component of the mucosa-associated lymphoid tissue (MALT) which works in the immune system to protect the body from invasion in the gut.
70% of immune system is
dedicated to the gut
why is 70% of the immune system dedicated to the gut
mouth is vulnerable entry into the body
o food is potentially very damaging
o gut has to be able to discriminate
e.g. spicy curry- stomach inflammation
distinction between pathogen trying to access blood stream and normal food
immune system is situated in
lymphatic and lymph organs
circulation of plasma and WBCs through interstitial space/tissues and back via lymphatics to lymph nodes allows
surveillance of tissues for foreign molecules and pathogens
LPS is
a potent activator of immunity
B-lymphocytes express
antibodies as B cell receptors
T-lymphocytes express
T cells receptors
during the adaptive immune response
B- and T-lymphocytes with receptors specific for particular pthogen molecules proliferate.
what forms the basis of protective immunity and immunological memory
clonal selection and expansion- protects the body be protected from future attacks
innate response comes first and involves
phagocytes
inflammatory cytokines
interferon-antiviral
cytokines
adaptive response involves
T cells
Antibodies
Cytokines
when does adaptive response start
day 6 after infection
example of how infection causes inflammation and swelling
1) bacteria trigger macrohages to release cytokines and chemokine
2) vasodilation and increased vascular permeability cases redness, heat and swelling
3) inflammatory cell migrate into tissue, releasing inflammatory mediators that cause pain
why does molecular and cellular interactions antigen recognition, cell signalling, cytokines and chemokine.. not lead to chaos….
But it doesn’t because the immune system has evolved to be a complex but very robust system that maintains homeostasis while at the same time being able to rapidly commit to particular courses of effector action to counter disease threats.
pathogens have
their own molecular signatures (antigens) known as PAMPs
pathogen recognition
Immune cells have invariant receptors on their surfaces known as PRRs that recongise many PAMPs.
Once a pathogen is recognised, a cascade of events occur- activating immune response to destroy it.
innate immunity
Binding of PAMPs by PRRs on phagocytic cells (e.g. macrophages in peripheral tissues) leads to an innate immune response.
FAST
requires no immunological memory
adaptive immunity
This response is slower and activated by a cascade of chemical signals form sites of infection, and physically interaction with Phagocytic cells of the innate immune system know as DENDRITIC CELLS that migrate from sites of infection into lymphatic system to activate LYMPHOCYTES.§
the extent to which the immune system are activated depends on
severity, context and
duration of disease - innate immunity is usually all that’s needed for a minor cut or splinter for example.
composition of RBC
44%
composition of WBC
1%
composition of Plasma
55%
serum
plasma without clotting factor
