U4 chapter 7 Flashcards
What does the immune system do?
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
Pathogen
A bacteria,virus,fungi or other microorganism causing disease
Antigen
molecule that interacts with the immune response, initiating an immune response. Depending on their source antigens are proteins,sugars,DNA and RNA
Self antigen
Located on surface of cell,marks an organism as “Self” so the immune system doesnt attack them.
What are class 1,MHC markers?
-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
What are class 2,MHC markers?
markers found in specialised cells of the immune system.
Non self antigen
-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.
Autoimmune disease
-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
allergies
-An overreaction to the presence of an allergen
-Allergens are antigens that the immune system recognise as non self.
Cellular pathogen
-Pathogen that has a cellular structure and exhibits the processes of a living organism
-Examples include; Bacteria, fungi,protozoa and parasites
Non-cellular pathogen
-Doesn’t have cellular structure nor exhibits the processes of living organism
-Examples include; Viruses and prions
What is the Major histocompatibility complex?
-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
Disease
when a pathogen is affecting the normal functioning of our cells
MHC class 1 markers
Expressed in all nucleated cells in the human body,majority of cells contain MHC class 1 markers
MHC class 2 markers
found in specialised cells of the immune system
Extracellular pathogen threat
Found outside of a cell, can interfere with its functioning (eg.bacteria)
Intracellular pathogen threat
-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
Bacteria (cellular pathogens)
-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
Fungi (cellular pathogen)
-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)
Worms (cellular pathogen)
-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)
Protozoa (cellular pathogen)
-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
Viruses (Non-cellular pathogen)
-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
Prions (Non-cellular pathogen)
-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)
Self pathogens
-Nucleated cells
-Specialised immune cells
List all cellular and non cellular pathogen types
Cellular pathogens
-Bacteria
-Worms
-Fungi
-Protoza
Non-cellular pathogens
-Virus
-Prions
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.
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
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.
Non specific
describes a component of the immune sytem that responds the same way to all pathogens.
What are the 2 types of barriers present in the first line of defence
Phyiscal and chemical
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
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)
Cuticle
Cuticle:waxy protective film covering the surface of a plat leaf
Gall
Abnormal outgrowth of tissue in plants designed to limit the spread of a invading pathogen
Trichomes
Small hairs on the surface of plants used to deter pathogen and or insects
Stomata
a small pore on the leaf surface that opens and closes to regulate gas exchange.
3 types of first line of defence Barriers in animals
First line defence;physical,chemical and microbiological barriers.
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
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
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
Microbiological
Presence of bacteria on the skin in the lower gastroinestinal tract and the vagina
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)
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
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.
Macrophage
a type of leukocyte found throughout the body that engages in phagocytosis and antigen presentation
Dendritic cell
type of leukocyte that engages in phagocytosis and antigen presentation
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
Cytokine
a signalling molecule released by cells (typically in the immune system) which aids in communicationg between immune cells and helps protect against pathogens