Chapter 8 - Immunity: Defence Against Disease Flashcards
immune system
a complex system made up of many components, including organs, tissues, specialised cells and specific molecules
able to identify self from non-self
self
material made by the body’s cell
non-self
foreign material
2 kinds of responses to invading foreign material:
non-specific (innate) immune response
specific (adaptive) immune response
non-specific (innate) immune response
immune responses react in the same way to all infections and have no ‘memory’ of prior infections
first 2 lines of defence
first line of defence
prevent entry of microorganisms into the body; surfaces intact skin mucous membranes natural secretions natural flora
intact skin
barrier against entry of microorganisms
keratin skin more impermeable
mucous membranes
respiratory and digestive tract
traps pathogens
cilia
natural secretions
tears (lysozyme burst bacteria)
saliva
stomach acid
natural flora
on or in the body skin gut vagina inhibits growth of pathogenic bacteria
second line of defence
non-specific and non-adaptive phagocytes natural killer cells complement proteins interferon cytokines inflammation blood clotting fever
phagocytes
macrophages and neutrophils
white blood cells that engulf and destroy microorganisms and other foreign material that enters the body by phagocytosis
enzymes released into the vesicle and its destroyed
natural killer cells
kill virus-infected cells before virus replicated
complement proteins
circulate blood activated by infection
stick to microorganisms more identifiable
stimulate phagocytes
interferon
proteins secreted by virus infected cells
Blocks viral protein synthesis in uninfected cells
Makes them more resistant to virus
cytokines
Cell communication
Helper T cells release them to stimulate other cells
inflammation
increase in blood flow to the area
phagocytes arrive and release histamine
promotes vasodilation (increase blood flow, more phagocytes)
blood clotting
tearing or puncturing of a blood vessel initiates clotting
triggered by release of clotting factors from the damaged cells
fever
makes body less favourable
stimulates helper T cells
creates inhospitable environment
steps of a fever
macrophages and phagocytes secrete interleukins
travel via bloodstream to hypothalamus
hypothalamus secretes prostaglandin
bodies thermostat reset to higher point (39)
antigens
proteins one every cells surface which act as recognition markers and have specific shapes
major histocompatibility complex (MHC)
genes that code for production of antigens all cells except red blood cells class 1 and 2 antigens
MHC class 1 antigens
located on the surface of virtually all human cells
MHC class 2 antigens
restricted to macrophages and the antibody-producing B-lymphocytes
non-self antigens
foreign antigens on cells not displaying MHC markers
non-self receptors
identify molecules or cells that are foreign to those of the immune system
the binding of a non-self antigen triggers immune response
self antigens
antigens on cells that are recognised by self receptors as being part of same body
self receptors
receptors used by cells to determine whether an encountered molecule or cell has structures that indicate it is part of the same body
antigen present cells (APC)
take up, process and present antigens to helper T cells become activated
examples of APC
phagocytes/macrophages
B-lymphocytes
dendritic cells
specific (adaptive) immune response
a specific immune response by the immune system to the particular antigen and result in adaptive/acquired immunity
3rd line of defence
involves production of memory cells
third line of defence
a specific response to a particular infection and results in adaptive or acquired immunity
humoral and cell mediated response
where do B and T cells mature
B lymphocytes mature in the bone marrow
leave before fully develop, travel to thymus gland and mature into T cells
Humoral immunity (B lymphocytes)
involving the transformation of B cells into plasma cells that produce and secrete antibodies to a specific antigen
immunoglobins (antibodies)
on B cell surface
proteins that identify antigens
specific structure and recognise only one type of antigen
what happens when a B cell encounters is complementary antigen
it replicates rapidly and produces numerous plasma cells
B cell don’t replicate without assistance of what
helper T cells
plasma cells
produce and secrete antibodies
Travel in blood and lymph
survive for a few days
B memory cells
produced from B cells antibody-antigen specificity survive for several years react faster and more vigorously creates 'immunity'
antibody
proteins produce in response to antigens
specific
antibody structure
4 polypeptide chains
2 long ‘heavy’ chains
2 shorter ‘light’ chains
hinge allows for flexibility
IgE
antibody
activates mast cells which release histamine for allergic responses
cell mediated immune response (T lymphocytes)
does not involve antibodies
involves the activation of phagocytes, cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen
does the cell mediated immune response make antibodies?
NOOOOO
where do T cells mature
thymus gland
helper T cells
activated when non-self antigens (macrophages) are presented to it
stimules B cells once activated
secrete a protein that stimulates other T and B cells
cytotoxic T cells
recognise and kills virus infected cells before has time to replicate
Can only kill virus when inside cell
suppressor T cells
regulate the action of the immune system
suppress action og phagocytes
slow production of antibodies and cytotoxic T cells
saves energy
suppressor T cells
regulate the action of the immune system
suppress action og phagocytes
slow production of antibodies and cytotoxic T cells
saves energy
lymphatic system
monitors the body for invading microorganisms
memory B and T cells circulate in lymph
what does swollen or sore lymph nodes indicate?
infection
acquiring specific immunity
recited from an outside source (passive) or antibodies can produced within the person (active)
active immunity
involves te production of antibodies within a person in response to exposure to a particular antigen
long lasting
natural or induced
natural active immunity
person comes in contact with a particular pathogen for the first time and produces antibodies
induced active immunity
vaccines
injected with dead of treated living microorganisms which trigger body to produce antibodies against the specific pathogen without causing disease
passive immunity
antibodies produced in one person and introduced into another can react with antigens to provide immunity
not long lasting
natural or induced
natural passive immunity
developing foetus receives maternal antibodies across the placenta
mothers breast milk
induced passive immunity
injected with antibodies obtained from blood plasma from donors who are known to have an infectious disease
serum
antibody serum
blood serum from tissues of immunised animals containing antibodies and used to transfer immunity to another individual
allergic response
allergy antigen
IgE antibodies produced
bind to mast cells
release histamine
histamine
causes symptoms associated with allergic responses
mast cells
fixed cells
contain larger amounts of histamine
autoimmune disease
immune system fails to identify ‘self’ from ‘non-self’ and causes antibodies to attack its own tissues
no cure
e.g. t1 diabetes, rheumatoid arthritis, multiple sclerosis
transplant organ rejection
translated tissue identified an ‘non-self’
T cells directly lyse foreign cells
immunosuppressant prevent this
plant barriers
physical and chemical defence mechanisms designed to protect and detect invading organisms
physical plant barriers
thick, waxy cuticle
thorns, spines and prickles
cork and galls form to limit spread
chemical plant barriers
proteins block growth antibacterial, anti fungal agents secreted oil repellents gum rapid apoptosis
Agglutination
Clumping of cells
Antibodies binding to antigens
Neutrophils
Engulf pathogen
Kill it and itself
Forms pus
Antibodies bound to pathogens can:
Damage
Stimulate phagocytosis
Activate compliment
Macrophages
Phagocytosis
APC to B and T cells
Release cytokines to induce inflammation
Activate antibody secretion
What do B cells differentiate into when activated?
Memory B cells
Plasma cells
