immune system Flashcards
1
Q
what is the function of the immune system
A
to protect against external and internal factors
2
Q
how does the immune body protect the body
A
via recognition and response
3
Q
what type of factors can the body recognise what what is the response
A
- immune system can recognise foreign factors which can either have a response of protection or a response of hypersensitivity due to an over reaction.
- immune system can recognise self and have an autoimmune response
4
Q
what are pathogens
A
disease causing microorganisms
5
Q
what can pathogens be split into
A
- microbes which consist of viruses, bacteria and fungi
- parasites which can be split into protozoa and helminths
6
Q
can viruses generate energy
A
no
7
Q
what does viral replication depend on
A
on the host (either eukaryotic or prokaryotic)
8
Q
what does the structure of a simple virus consist of
A
- nucleic acid genome= single or double stranded RNA or DNA
- capsid (protein coat)
this overall structure is called a nucleocapsid - some viruses have an envelope
9
Q
describe bacteria
A
- are prokaryotes (don’t have a nucleus)
- their classification is based on morphology and structure of bacterial wall
10
Q
describe morphology as a type classification of bacteria
A
this is the shape of the bacteria which can either be bacilli (rod shaped) or cocci (sphere)
11
Q
describe structure as a type of classification of bacteria
A
- the bacteria can either be gram positive or gam negative
- gram positive= when have a cell membrane and thick peptidoglycan cell wall
- gram negative= when have a cell membrane, a thin peptidoglycan cell wall and an outer membrane which consists of lipopolysaccharides
12
Q
describe bacterial endo and exo-toxins
A
- endotoxins= are released from lipopolysaccharides. lipopolysaccharide structure consist of 2 parts (top and bottom) called immunogenicity (top) which is the ability of producing antibodies. toxicity (bottom) is the release of inflammatory cytokines
- exotoxins= they are secreted in the environment. these toxins are potent and specific and target crucial host enzymes
13
Q
what is toxoid
A
toxins that lost toxicity but are still able to induce antibodies which then provide protection (immune response)
14
Q
do endo or exotoxins form toxoid
A
exotoxins
15
Q
describe fungi
A
- are eukaryotes (have a nucleus) eg, moulds, yeast and higher fungi
- there are approx 1 million species and approx 400 that are pathogenic to humans
16
Q
what are the different morphological forms of fungi
A
- yeast= unicellular and reproduce asexually by budding
- hyphae= multicellular and reproduce sexually or asexually
- dimorphic= can switch between yeast and hyphal forms
17
Q
what does a fungal cell wall consist of
A
- mannoproteins
- glucans
- chitin
- phospholipid bilayer
18
Q
what is the function of chitin
A
protective layer
19
Q
describe protozoa (type of parasite)
A
- unicellular eukaryotes (have a nucleus)
- in humans they are smaller than 50 micrometers
20
Q
how are protozoa classified
A
based on mode of movement:
- flagellates= tail
- ciliates= shaped like amoeboids (blob) but move with little hairs
- amoeboids= blob moving around
- phylum sporozoa= no movement in adult stage
21
Q
describe helminths (worms)
A
- multicellular invertebrates
22
Q
how are helminths (worms) classified
A
- tapeworms= segmented hermaphroditic flatworms
- roundworms= bisexual
- flukes= leaf shaped flatworms
23
Q
what does the lymphatic system consist of
A
lymph, lymph vessels, organs and tissues
24
Q
what can lymph organs be split into
A
primary and secondary lymphoid organs
25
what are the primary lymphoid organs
bone marrow and thymus
26
what are the secondary lymphoid organs
spleen, lymph nodes
27
what does lymph contain
leukocytes, nutrients and waste
28
how does lymph travel through lymphatic vessels and nodes
enters the lymph node through the afferent vessel its then filtered and leaves the node via the efferent vessel and returned back to the blood specifically veins near the heart.
29
how is lymph made
blood separates into plasma. interstitial fluid is then made by leaving the blood vessel by high blood pressure. the interstitial fluid is then absorbed into lymphatic capillaries so turns into lymph.
30
what is the function of lymphatic vessels and lymph
- to drain excessive interstitial fluid
- transport dietary lipids (such as vitamin A, D,E) absorbed in the GIT
- immune function= transport lymphocytes around the body and pathogens from affected areas to lymph nodes
31
what happens if filtered lymph isn't returned back into the blood
swelling occurs due to excess
32
describe primary lymphatic organs
- bone marrow and thymus
- function is the maturation of t and b lymphocytes
33
describe secondary lymphatic tissues and organs
- spleen, peyer's patches and lymph nodes
- function is recognise the antigen which causes the activation of the t and b cells and leads to an immune response
34
describe the bone marrow (type of primary lymphatic organ)
- it's a source of all blood cells (from haematopoietic stem cells)
- their function is the maturation of B lymphocytes
35
describe the thymus (type of primary lymphatic organ)
- function is the maturation of T lymphocytes
- responsible for the selection of t lymphocytes= either positive or negative selection
36
describe the function of the spleen (type of secondary lymphatic organ)
- spleen consists of red and white pulp
- red pulp function= firstly, the removal of rupture, old RBCs by macrophages, storage of platelets and site of haematopoiesis in foetal development
- white pulp function= cause the activation of t and b lymphocytes and macrophages carry out phagocytosis of blood borne pathogens
37
describe the function and structure of lymph nodes
- function= they regulate immune response and are exposed to antigens which causes the activation of t and b lymphocytes
- structure= cortex with follicles (contain b cells, macrophages and dendritic cells), paracortex (contains t cells and dendritic cells) and medulla (contains mature b cells and macrophages)
38
name the 2 systems of immunity
innate and adaptive
39
describe the innate system of immunity
- it's the first line of defence
- rapid response due to fixed recognition of elements
- it has limited specificity (not specific)
- no memory (suggests can remember if has already defended body against pathogens already)
40
describe the adaptive system of immunity
- it's the second line of defence
- slow response due to a variety of recognition elements
- highly specific
- immunological memory
41
what can the innate system of immunity be split into
- primary protective cells
- cells
- molecules -> can be further split into soluble (eg, complement and cytokines) and cell associated
42
what can the adaptive system of immunity be split into
- cells
- molecules -> split into soluble (eg, cytokines and antibodies) and cell associated (eg, B and T cell receptors)
43
what do receptors do
they monitor the change in environment
44
what is the biochemical structure of receptors
they are proteins which go through post translational modifications such as phosphorylation
45
what is the location of mature receptors
cell surface receptors= receptors are embedded on the cellular plasma membrane such as t and b cell receptors
46
what are types of intracellular receptors
- nuclear receptors
- cytoplasmic receptors
47
what do intracellular receptors do
they help protect body against intracellular pathogens
48
what are the functions of receptors
they bind to molecules such as neurotransmitters, antigens, peptides, hormones, drugs. this causes a conformational change in the receptors which has a downstream effect like:
- activation of signalling cascade which leads to change in gene expression
- change in membrane potential causing muscle contraction
- change in cytoskeleton causing endocytosis in phagocytosis
49
what are cytokines and chemokines
soluble molecules
50
what is the biochemical structure of cytokines
low molecular weight proteins
51
how are cytokines released
by cells the immune system and other systems in response to changes
52
what are the functions of cytokines
- they are messengers
- they bind to cell surface receptors and induce changes in target cells by passing signals
- they don't kill
53
what are the modes of actions of cytokines
- autocrine
- paracrine
- endocrine
54
describe autocrine as a type of action of cytockines
the cytokines released interact with receptors on themselves
55
describe paracrine as a type of action of cytokines
cytokines released interact with receptors on a nearby cell
56
describe endocrine as a type of action of cytokines
the cytokines released move through the circulation to interact with receptors and a distant cell
57
what are the functions of cytokines and chemokines
- communication and interactions
- activation= TH1 lymphocytes activate macrophages
- differentiation
- proliferation
- cell death and survival
- chemotaxis (by chemokines)
58
what are the different cytokine classifications (cytokine families)
- haematopoietin family= interleukins
- chemokine family= chemotaxis, adhesion
- tumour necrosis factor family= regulate inflammation
- interferon family= anti viral function
59
what is the major histocompatibility complex split into
class 1 and 2
60
what are MHC class 1 and 2 proteins and what do they do
- they are membrane bound glycoproteins
- present antigens on cell surface
61
describe MHC class 1
- they only express endogenous antigens
- they are expressed on the surface of every nucleated host cell
62
describe MHC class 2
- they are expressed only on surface of professional antigen presenting cell
- only exogenous antigens are expressed
63
what is the complement
it is more than 30 soluble ,cell bound proteins produced by the liver and other cells of the immune system
64
what is the function of the complement
- for recognition and detection of extracellular pathogens which is done by:
- lysis of cells, bacteria, viruses
- by tagging pathogenic organisms making them visible to immune cells for destruction which leads to phagocytosis (this is called opsonisation).
- trigger inflammation and release of cytokines
65
what is the biochemical structure of antibodies
it is a soluble glycoprotein produced by B lymphocytes
66
what are the functions of antibodies
- tag pathogenic organisms making the visible to immune cells for destruction= called opsonisation
- activates the complement
- neutralises pathogenic organisms, toxins and molecules
- activate immune cells to attach pathogens
- causes degranulation of immune which leads to allergic reactions
67
what are the classes of antibodies
- IgG, IgD, IgE= monomers
- IgA= monomers and dimers
- IgM= pentamers
68
name the lymphoid stem cells
T and B lymphocytes
69
name the myeloid stem cells
- natural killer cells
- macrophages
- dendritic cells
- monocytes
Granulocytes such as=
- neutrophils
- basophils
- eosinophils
- mast cells
70
