U4 chapter 7 Flashcards
1
Q
What does the immune system do?
A
By using antigens the immune system recognises if a cell or molecule is self or non self.If found to be non self an immune response is initiated
2
Q
Pathogen
A
A bacteria,virus,fungi or other microorganism causing disease
3
Q
Antigen
A
molecule that interacts with the immune response, initiating an immune response. Depending on their source antigens are proteins,sugars,DNA and RNA
4
Q
Self antigen
A
Located on surface of cell,marks an organism as “Self” so the immune system doesnt attack them.
5
Q
What are class 1,MHC markers?
A
-expressed on all nucleated cells in the body
-present on almost all of human cells except for those without a nucleus such as red blood cells
6
Q
What are class 2,MHC markers?
A
markers found in specialised cells of the immune system.
7
Q
Non self antigen
A
-Molecule formed outside the body, recognised by the immune system initiating an immune response
-Also known as a foreign antigen
-if a non self antigen is recognised the immune system is activated and attempts to eliminate it.
8
Q
Autoimmune disease
A
-disease in which an individuals immune system intiate an immune response against their own cells
-happens when the immune system mistakes self antigens as non self,resulting in a system attacking cells
9
Q
allergies
A
-An overreaction to the presence of an allergen
-Allergens are antigens that the immune system recognise as non self.
10
Q
Cellular pathogen
A
-Pathogen that has a cellular structure and exhibits the processes of a living organism
-Examples include; Bacteria, fungi,protozoa and parasites
11
Q
Non-cellular pathogen
A
-Doesn’t have cellular structure nor exhibits the processes of living organism
-Examples include; Viruses and prions
11
Q
What is the Major histocompatibility complex?
A
-In verterbrates the most important self antigens take the form of the major histocompatibility complex .
-group of proteins present on the surface
of all self-cells that enables the
immune system to distinguish
it from non-self material
-Also known as MHC proteins, MHC
molecules, or self-antigens
-MHC can be divided into to classes, class 1 and class 2
-differ on every human body
12
Q
Disease
A
when a pathogen is affecting the normal functioning of our cells
13
Q
MHC class 1 markers
A
Expressed in all nucleated cells in the human body,majority of cells contain MHC class 1 markers
14
Q
MHC class 2 markers
A
found in specialised cells of the immune system
15
Q
Extracellular pathogen threat
A
Found outside of a cell, can interfere with its functioning (eg.bacteria)
16
Q
Intracellular pathogen threat
A
-Found within a cell tat can interfere with its functioning
-Can include pathogens such as viruses that invade cells, however can also include pathogen threats such as cumulative mutations to DNA that can lead to the development of cancer
17
Q
Bacteria (cellular pathogens)
A
-Unicellular prokaryotes that can infect any part of the body
-cause disease through production of toxins and enzymes, effect functioning or cause cell death
-reproduce asexually through binary fission
-Examples include; Neisseria meningitdis causing meningitis and clostridium tetani causing tetanus
18
Q
Fungi (cellular pathogen)
A
-Eukaryotic organisms including yeasts and molds, contain long branching filaments called hyphae
-Reproduce through asexual reproduction and sexual reproduciton via spore formation
-Examples include; thrush, trichopyton spp,causing athletes foot (Tinea pedis)
-Ringworm (Tinea)
19
Q
Worms (cellular pathogen)
A
-Multicellular invertebrate parasites whose development include egg, larval and adult stages
-Vary in length, longest are 55cm
-Worms reproduce sexually via a complex life cycle
-Examples include; Parasites (tapeworm) infection leading to malnutrition, Roundworm (ascarias)
20
Q
Protozoa (cellular pathogen)
A
-Single-celled eukaryotes that can be free living or parasitic
-Have many different mechanisms of action, some can inhibit nucleic acid synthesis,protein synthesis and various stages of cellular respiration
-Protozoa reproduce both through asexual reproduction and sexual reproduction
-Plasmodium causing malaria
21
Q
Viruses (Non-cellular pathogen)
A
-Infectious agent composed of genetic material (DNA or RNA) inside a protein coat (capsid)
-cause disease through the lysis of cells during viral replication, the formation of cancer by affecting gene expression, and the over stimulation of the immune system leading to organ damage
- Not able to independently reproduce.Instead, they insert genetic material into hosts cell and uses cells machinery to replicate
-Examples include; rhinovirus causing the common cold,influenza causing the flu, ebola virus causing ebola, SARS-Cov2 causing Covid-19
22
Q
Prions (Non-cellular pathogen)
A
-Abormally folded proteins that have the ability to induce normal proteins nearby to become misfolded
-Only occur in mammals and affect only the brain and other neural structures
-Only known infectious agents that dont include nucleic acids
-Do not reproduce typically, instead “spreading” the infection by causing other proteins to misfold
-Examples include; Creutzfeldt-jakob disease, Bovine spongiform encephalopathy (also known as mad cow disease)
23
Q
Self pathogens
A
-Nucleated cells
-Specialised immune cells
24
List all cellular and non cellular pathogen types
Cellular pathogens
-Bacteria
-Worms
-Fungi
-Protoza
Non-cellular pathogens
-Virus
-Prions
25
First line of defence
A compontent of the innate immune system characterised by the presence of physical,chemical and microbiological barriers to keep pathogens out of the host organism.
26
Second line of defence
component of the innante immune system characterised by the non specific response to injury and or pathogens by a variety of cells and molecules
27
Innate immune system
-A component of the immune system that is composed of generalised and non specific defences and or responses to pathogens
-Also known as the non specific immune system.
-Involve a non specific response to foreign antigens,responding the same way regardless of the type of pathogen or antigen present
-respond to injury and antigens extremely quickly.
28
Non specific
describes a component of the immune sytem that responds the same way to all pathogens.
29
What are the 2 types of barriers present in the first line of defence
Phyiscal and chemical
30
What is a Physical barrier?, name examples of physical barriers in plants
a component of the first line of defence that features solid, or fluid obstacles, that features solid or fluid obstacles that block pathogen entry such as skin or mucus.
examples include;
-Thick bark
-Waxy cuticles of leaves
-Formation of galls to prevent the spread of infection
-Presence of thorns and trichomes to deter insects and grazers
-Closing of stomata to prevent pathogen invasion during carbon dioxide uptake
31
what is a Chemical barrier?,name examples in plants
a component of the first line of defence that features the use of enzymes, toxins, and acids to protect against pathogen invasion.
Examples include;
-Chitinases(enzymes containning antifungal properities)
-Phenol (secretated by wounded plants, repelling and killing invading microorganisms)
-defensins (small peptides that are toxic to microbes and fungi)
-Saponins (disrupt cell membranes of various fungi)
-Oxalic acid (substance toxic if ingested)
-Glucanases (defend plants against fungi)
32
Cuticle
Cuticle:waxy protective film covering the surface of a plat leaf
33
Gall
Abnormal outgrowth of tissue in plants designed to limit the spread of a invading pathogen
34
Trichomes
Small hairs on the surface of plants used to deter pathogen and or insects
35
Stomata
a small pore on the leaf surface that opens and closes to regulate gas exchange.
36
3 types of first line of defence Barriers in animals
First line defence;physical,chemical and microbiological barriers.
37
Microbiological barrier
Component of the first line of defence in which the presece of normal flora limits the growth of paathogeic bacteria.Also known as microbiota barrier
38
Physical barriers in animals
-Intact/healthy skin and surfaces between internal and external environments (eg. integumentary, respiratory, gastrointestinal and genitourinary tracts)
-Mucous secretion and/or hairs in the respiratory tract that trap organisms and cillia that sweep them away from the airways and the throat where they are swallowed and destroyed by the gastrotestinal tract
39
Chemical barriers in animals
-presence of lyosozyme enzymes in tears and saliva that destroy bacterial cell walls
-acidic sweat that destroys pathogens growing on the surface of the body
-Stomach acid that destroys pathogens that have been eaten/swallowed
-Antibacterial compounds in earwax
-Antibacterial proteins in semen
-Low pH in the vagina
40
Microbiological
Presence of bacteria on the skin in the lower gastroinestinal tract and the vagina
41
cellular components or the second line of defence
-All cells involved are called leukocytes (group of blood cells responsible for protecting the body against pathogens and foreign material, also known as white blood cells)
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Phagocytes
-group of leukocytes responsible for endocytosis and destructution of pathogens,foreign material and cell debris
-To communicate within the immune system, phagocytes release a number of substances such as cytokines
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Neutrophil
the most common type of leukocyte in the body.Engages in phagocytosis of pathogens and foreign mateiral as well as the release of cytokines.
44
Macrophage
a type of leukocyte found throughout the body that engages in phagocytosis and antigen presentation
45
Dendritic cell
type of leukocyte that engages in phagocytosis and antigen presentation
46
Antigen-presenting cell
-subgroup of phagocytes that display antigens from consumed pathogens on their surface and interact with the adaptive immune system
-Also known as professional antigen-presenting cell
47
Cytokine
a signalling molecule released by cells (typically in the immune system) which aids in communicationg between immune cells and helps protect against pathogens
48
Natural killer (NK) cell
-A type of leukocyte responsible for recognition and destruction of damaged and or infected hosts cells
-Natural killer cells are large granulated cells which target both abnormal and virally infected cells
-Achieved with the presence of 2 receptors, a killer inhibitory receptor and a akiller activation receptor.
49
Killer inhibitory receptor
-examines the surface of cells for MHC class 1 markers
-If the killer inhibitory receptor detects a sufficient number of MHC class 1 markers, then it overrides the killer activation signal,preventing cell death
50
Killer activation receptor
binds to certain molecules which appear on cells undergoing, cellular stress.
51
Mast cell
-type of leukocyte responsible for releasing histamine durng allergic and inflammatory responses
-Mast cells are found in connective tissue throughout the body, when they detect injury to surronding cells or are stimulated by antigens or allergens they become activated and degranulate releasing histamoine.
52
Degranulation
release of granule contents from a cell
53
Histamine
molecule released by mast cells that plays a key role in inflammation
54
Inflammatory response
-series of biochemical events that occur in the body as a result of infection and/or trauma
-Characterised by swelling,redness,pain and heat in the affected tissue.
55
Eosinophil
-large granular leukocyte responsible for the release of toxic chemical mediators
-typically target pathogens which are too large to be phagocytesd by degranulating on contact with them, releasing chemical mediators contained within their granules.
56
Interferferon
cytokine released by virally infected cells that increases the viral resisteance of neighbouring uninfected cells.
57
Complement proteins
-number of different types of proteins found in the blood that opsonise cause lysis and attract phagocytes to invading pathogens.
-When a number of different complement proteins are together, they form the complement system.In the presence of certain pathogens, thee proteins began reaction with each other in a series called the complement cascade.
58
3 major outcomes of complement cascade
Opsonisation,chemotaxis and lysis
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Opsonisation
-First stage of complement cascade
-complement proteins stick on the outside of surface of pathogens and make it easier for cells of the immune system,such as phagocytes
60
Chemotaxis
-Second stage of complement cascade
-Complement proteins gather near a pathogen and attract phagocytes to it,making it more likely to be destroyed
-(attraction of phagocytes towards a pathogen )
61
Lysis
-Third stage of complement cascade
-Complement proteins can join together on the surface forming a membrane attack complex (MAC), this creates pores
-(disintegration or rupturing of a cell)
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Membrane attack complex (MAC)
a pore formed by complement proteins in the cell membranes of a pathogen,disrupting the membrane and leading to the pathogens destruction.
63
Fever
-temporary increase in body temperture:an innate response to potential infection, as many pathogens cannot survive at elevated temperatures
-Helps support the immune system by activating certain proteins in the body that help with the strength with the bodies defences
-Prolonged fevers can be detrimental to the body.Since the cells are no longer functioning at their optimal temepratures
64
Inflammatory response
designed to eliminate the effects of an injury,defend against potential pathogens,clear out cells that may have been damagaed or destroyed and initiate repair.
65
3 steps of the inflammatory response
Intiation, Vasoldilition and migration
66
initiation
Involves cytokines being secreted by activated macrophages and damaged cells.Additionally,mast cells degranulate releasing histamine.
67
Vasoldiliation
-widening of blood cells
-histamine released from mast cells travel to nearby blood vessels,binding to specific receptors, causing vasodilation.This causes blood vessels to widen, increasing blood flow to injury site, causing swelling,redness and warmth. Additionally, the formation of gaps in the vessel wall increasing the permeability to cells of the immune system.
68
Migration
-Vasodilation and the increased leakiness of blood vessels allows for a number of innate immune system components to leave the bloodstream and enter the site of injury, these components include
69
Phagocytes
-including macrophages and neurtrophils, guided by the cytokines secreted by activated macrophages and damaged cells to the site of injury.Here they phagocytose pathogens and digest them using enzymes such as lysozymes
-Complement proteins are attracted to pathogens and make it easier for phagocytes to detroy them.
70
Third line of defence
-Also known as adapative immune system or speific immune system
-Subset of the immune system within the vertebrates that is composed of the humoral and cell-mediated responses which create a specific immune response and form immunilogical memory.
-A key process in the initiation of the adaptive immune response involves the selection of a type of T lymphocyte called a T helper cell via a process called antigen presentation.
71
2 unique features of the Adaptive/specific immune system
Specificity and immunological memory
72
Specificity
the adaptive immune system responds to each distinct pathogen in a unique or tailored manner
73
Immunological memory
adaptive immune system results in the production of cells that allow the body to response to future reinfections by a previously encountered pathogen quickly and effectively.(immunological memory is the ability of the immune system to quickly and agressibly combat a previously encountered pathogen due to the presence of T and B memory cells)
74
T lymphocyte
type of lymphocyte that plays an important role in cell-mediated immunity.Differentiates into cytotoxic t cells, t memory cells and T helper cells.
75
T helper cell
Type of differentiated T lymphocyte that supports the functioning of a number of different immune cells, including the cloning and differentiation of selected T and B cells.
76
Lymphatic system
Large network of vessels and tissues throughout the body that form an important component of both the circulatory and immune systems.
77
Lymph node
Small secondary lymphoid tissue of the lymphatic system where antigen-presenting cells activate the adaptive immune system
78
Lymph node
Small secondary lymphoid tissue of the lymphatic system where antigen-presenting cells activate the adaptive immune system
79
Antigen presenting cells (APCs)
engulf and digest pathogens via phagocytosis.After this process they travel via the lymphatic system to lymph nodes to present foreign antigens on their surface using MHC class 11 proteins.These then intereac with complementary T cell receptors for a single antigen on its surface,facilitating the specificity of the adaptive immune response.
When this interaction happens, the T helper cell becomes activated and is said to be "selected" the activated T helper cell can then help initiate the adaptive immune response through either the humoral or cell meditated immune response.
80
Humoral immunity
An adaptive immune response in which extracellular pathogens are targeted by specific antibodies produced by plasma cells.Also known as B cell immunity
81
Cell mediated immunity
an adaptive immune response in which infected or abnormal cells are destroyed by cytotoxic T cells, Also known as T cell immunity.
82
B lymphocyte
type of lymphocyte that plays an important role in humoral immunity and differentiates into plasma cells and B memory cells.
83
Antibody
a protein produced by Plasma cells during the adaptive immune response that is specific to an antigen and combats pathogens in a variety of ways.Also known as immunoglobulin.
84
Cytokine
signalling molecule released by cells (typically in immune system) which aids the communication bettern immune cells and helps protect against pathogens.
85
Clonal expansion
process in which many copies of lymphocyte are generated
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Clonal selection
process in which B and T cells encounter an antigen that matches their antigen binding site and then generate many copies of themselves, also known as clonal selection theory.
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Differentiation
process in which cells develop specialised characteristics,typically transofrmming them from one cell type to another more speciliased cell
88
B memory cell
-A differentiated B lymphocyte that is responsible for providing long-lasting immunlogical memory of an antigen
-B memory cells contribute to immunological memory by rapidly dividing and forming new antibody producing plasma cells when they encounter an antigen that matches their receptor
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Effector cell
a cell that responds to a signal and produces a response
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Plasma cell
a differentiated B lymphocyte that is responsible for the generation and secretion of antibodies during the humoral response
91
Humoral immunity steps
1.A pathogen with an antigen that is complementary in shape to the antigen binding site on the receptor of a B cell interacts with that B cell.When this occurds the B cell is said to have been selected.
2.Once a B cell has been selected, a helper T cell selected through antigen presentation (which also has a complementary receptor to the antigen) will recognise the selected B cell and secrete a number of different cytokines.These cytokines cause the B cell to undergo clonal expansion, through which many copies of the selected B cell are produced.The process of selecting a specific T helper and B cell is termed clonal selection theory
3.The T helper cell then simulates the selected B cell via cytokines to undergo the process of differentiation, in which the clones of the selecte B cell are driven to differentate into 2 different types of B cells,
B memory cells and effecotr cells (plasma cells)
4.Plasma cells are differnetiated clones the selected B cell.After differentiating they secrete antibodies into the blood in order to defend against the selected pathogens.
92
Antibodies
released by plasma cells are proteins with quartenery structure.They are composed of four polytpeptide chains, including 2 heavy chains and 2 light chains, arranged into a "y" shape. The 2 heavy chains are joined by a sulphide bond (a strong covalent bond occuring between 2 sulphur atoms).Each anti body has 2 regions, the stem of the anti body is known as the constant region, and the tops of the "arms" are known as the variable region. These regions come together to form 2 identical binding sites for the same specific complementary antigen. This allows antibodies to bind with antigens on the surface of pathogens.As there are 2 binding sites present, an antib ody can bind with 2 pathogens at once.
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Agglutination
-Function of antibody
-Antibodies can bind together with antigens on two separate pathogens,forming large antigen-antibody complexes.This makes it easier for phagocytes to recognise the pathogens as foreign bodies and destroy them.
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Immobilisation
-Function of antibodies
-Antibodies can also restrict the movement of pathogens around the body through the formation of large antigen-antibody complexes
95
Opsonisation
-Function of antibodies
-Antibodies can bind directly to the surface of a pathogen to make it easier to phagocytise
96
Activation of complement proteins
-Function of antibodies
-Antibodies attached to the surface of pathogens can facilitate the actions of complement proteins,including the formation of membrane attack complexes.
97
Membrane attack complex (MAC)
- pore formed by complement proteins in the cell membranes of a pathogen,disrupting the membrane and leading to the pathogens death.
97
Neutralisation
-Function of antibody
-Can block the site of pathogens that are used to attack host cells (eg. the site used by a virus to enter a cell) and can block the active sites of toxins
98
Rhesus antigen
-an antigen on the surface of red blood cells that can cause an immune response if not matched correctly between donor and reciever.
99
Rhesus antigen
-an antigen on the surface of red blood cells that can cause an immune response if not matched correctly between donor and reciever.
100
medited immunity, involves the destruction of infected or abnormal cells via the clonal selection of a cytotoxic T cell
101
cell medited immunity
involves the destruction of infected or abnormal cells via the clonal selection of a cytotoxic T cell
102
Cytotokic T cell
-a differentiated T lyphocyte that is responsible for the destruction of infected or abnormal cells.
-cells, which are a type of T lymphocyte, are the key players of cell-mediated immunity.They primarily carry out their role by assesing the MHC class 1 marker of infected cells
103
Cell mediated immune response
1.At the same time as the selection of T helper cells,antigen-presenting cells eventually come upon a naive T cell with a T cell receptor that matches the antigen being presented, initiating the process of clonal selection.When this occurs, the naive T cell becomes selected and is stimulated by cytokines released by the selected T help cell to undergo the processes of clonal expansion and differentiation.
2.The clones of the selected T cell differentiate into 2 types of T cells-effecotr cells called cytotoxic T cells and T memory cells.T memory cells,like B memory cells are copies of the originally selected T cell that reside in the body for extended periods of time and help form immunological memory.the majoryity of selected T cells differentiate into cytotoxic T cells, which leave the lymph node and travel througout the body,eventually reaching the site of infection.
3.Due to the process of clonal selection the cytotoxic T cells that arrive at the site of infection all have T cell receptors that are specific to the foreign antigen selected for.once the cytotoxic T cell has found an abnormal cell that is presenting complementary foreign antigens on its MHC class 1 complex.It bins to it a via interactions
104
T memory cells
proliferate rapidly into T helper cells and cytotoxic T cells upon stimulation by an antigen-presenting cell that is presenting a previously encountered antigen
105
Immunological memory
-B memory cells and T memory cells fomed during the adaptive immune response remain in the blood for an extended period of time,allowing the body to respons to pathogen it has previously encountered quickly and effectivly
-A key component of both the humoral and cell-mediated adaptive immune responses is the creation of B and T memory cells,respectivly.each of these cells confers the body with long lasting immunological memory
106
Lymphatic system
-large network of vessels and tissues throughout the body that form an important component of both the circulatory and immune system
-comprised of a series of lymphatic vessels throughout the body that function to transport lymph (a plate fluid that flows through the lymphatic system and has ahigh concentration of leukocytes )
-has 2 primary functions, to act as a transport system for antigen-presenting cells and pathogens, and to serve as the location of clonal selection.
107
Circulatory system:
collection of tissues and organs involved in the transportation of substances around the body.Vomposed of the lymphatic and cardiovascular systems
108
Functions of the lymphatic system:
-transportation of antigen presening cells (subgroup of phagocytes that display the antigens from consumed pathogen on their surface and interact with the adaptive immune system) to secondary lymphoid tissues (components of the lymphatic system that are responsible for the maintenance of mature lymphocytes and the activation of the adatpive immune response.Includes lymph nodes and the sspleen) for antigen recognition and initiation of the adaptive immune response.
-Production of leukocytes,including lymphocytes in primary lymphoid tissues (components of the lymphatic system that are responsible for the production and maturation of lymphocytes.includes bone marrow and the thymus)
-removal of flud from tissues around the body
-Absorption of fatty acids from the digestive system.
109
Primary lympohoid tissues
Are responsible for the creation and maturation of lymphocytes.The main primary lymphoid tissues include the bone marrow and the thymus
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Bone marrow
semi solid tissue found within bones.Serves as the primary site of the creation of blood cells and leukocytes
111
Thymus
Primary lymphoid organ located in the chest.Serves as the site of T cell maturation
112
Secondary lymphoid tissues
-responsible for maintaing mature lymphocytes and initiating the adaptive immune response. The main secondary lympohoid tissues include the lymph notes (eg. Tonsils) and the spleen.
-In these tissues mature lymphocytes are clustered together and "scan" passing lymph for the presence of any pathogens or antigen presenting cells.if a foreing antigen matches the receptors of specific lymphocytes.These lymphocytes then undergo clonal selection and differentiation.This results in a large number of B and T cells being created within these tissues,resulting in the characteristic swelling of lymph nodes when your sick.
113
Lymph node
small secondary lympohoid tissue found throughout the body where antigen-presenting cells activate the adaptive immune system
114
Tonsils
2 lymph notes residing in the back of the throat
115
Spleen
organ located in the upper abdomen that serves as a variety of functions in the immune sytem and the regulation of red blood cells
116
Lymphatic drainage
Fluid from blood vessels constantly leaks into the tissues of the body.leakage is increased during an inflammatory response to allow for the movement of leukocytes into tissues. Lymphatic capillaries are extremely small vessels that exsist throughout the tissues of the body,collecting fluid in tissues as well as any pathogens that might be present. Once this clear fluid enters the lymphatic capillaries it is known as lymph and is carried away into the lymphatic system.Where it eventually arrives at a lymph node
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Lymphatic flow
The small lymphatic capillaries throughout the body gradually join together to form larger vessels that contain an increasing amount of lymph. These vessels have thin walls and rely on surronding muscle movements to squeeze lymph fluid through the system.the heart is not response for responsible for pumping lymph.
118
Afferent lymphatic vessels
thin walled structures that collect lymph from the tissues of the body and deliver it to lymph nodes
119
Efferent lymphatic vessels
thin walled structures that collect lymp that has drained through lymph nodes reutrning it back to circulation
