Investigate and model the innate and adaptive immune systems in the human body
Investigate and model the innate and adaptive immune systems in the human body (ACSBL119)
Immune System:
- A collection of biological structures, organs and processes that protects an organism from the invasion of harmful pathogens and helps it to fight against the effects that occur due to the invasion of the pathogen.
Innate Immune System:
- This immune system goes into action as soon as a pathogen comes in contact of the host.
- It is the dominant system of defence in most hosts and includes surface barriers and cellular barriers.
- The surface barriers are the first line of defence and is comprised of a range of mechanical, physical and chemical barriers.
- Mechanical barriers include the waxy cuticle of most leaves, the exoskeleton of insects, the shells and membranes of externally deposited eggs, and skin etc. A range of secretions from the mechanical barriers act as chemical barriers and are mostly a range of antimicrobial peptides and enzymes.
- The cellular barriers include a number of cells such as macrophages, mast cells, neutrophils, eosinophils, basophils, natural killer cells, dendritic cells.
- Functions of some of these cells are:
- Macrophages hunt down pathogens and kill them in a process called phagocytosis.
- Mast cells play an important role in wound healing and defence against pathogens via the inflammatory response.
- Neutrophils are the first cells to arrive at the site of infection and can stop pathogens from proliferating. Pathogens also die when they come in contact with Neutrophils.
- Eosinophils can secrete a range of highly toxic proteins and free radicals that kill bacteria and parasites.
- Similar to mast cells, basophils are also key players in mounting an allergic response.
- Natural Killer cells (NK cells), do not attack pathogens directly instead, they destroy infected host cells in order to stop the spread of an infection.
- Dendritic Cells can identify threats and act as messengers for the rest of the immune system by antigen presentation.
Adaptive Immune System:
- This system is antigen specific and goes into action after the host has already been exposed to that particular antigen before.
- Cells of the adaptive immune system have immunological memories, which means they actually ‘remember’ a pathogen from its previous attack and thus have build up a response against it the next time that particular pathogen enters the body.
- The adaptive immune system consists mostly of lymphocytes, killer T cells, helper T cells, B lymphocytes and antibodies, immunological memory.
- Their functions are:
- Lymphocytes are a special type of leukocyte and consist of B cells and T cells which carry receptor molecules that recognize specific targets.
- Killer T cells are a sub-group of T cells responsible for killing cells that are infected with viruses (and other pathogens), or are otherwise damaged or dysfunctional.
- Helper T cells regulate both the innate and adaptive immune responses and help determine which immune responses the body makes to a particular pathogen.
- A B cell identifies pathogens when antibodies on its surface bind to a specific foreign antigen. Antibodies can also neutralize challenges directly, by binding to bacterial toxins or by interfering with the receptors that viruses and bacteria use to infect cells.
- When B cells and T cells are activated and begin to replicate, some of their type become long-lived memory cells which, throughout the lifetime of an animal, each specific pathogen encountered and can develop a strong response if that pathogen invades the body again.
Extract from HSC Biology Stage 6 Syllabus. © 2017 Board of Studies NSW.
EasyBio > Infectious Disease > Immunity > Investigate and model the innate and adaptive immune systems in the human body
Investigate and model the innate and adaptive immune systems in the human body (ACSBL119)
Immune System:
- A collection of biological structures, organs and processes that protects an organism from the invasion of harmful pathogens and helps it to fight against the effects that occur due to the invasion of the pathogen.
Innate Immune System:
- This immune system goes into action as soon as a pathogen comes in contact of the host.
- It is the dominant system of defence in most hosts and includes surface barriers and cellular barriers.
- The surface barriers are the first line of defence and is comprised of a range of mechanical, physical and chemical barriers.
- Mechanical barriers include the waxy cuticle of most leaves, the exoskeleton of insects, the shells and membranes of externally deposited eggs, and skin etc. A range of secretions from the mechanical barriers act as chemical barriers and are mostly a range of antimicrobial peptides and enzymes.
- The cellular barriers include a number of cells such as macrophages, mast cells, neutrophils, eosinophils, basophils, natural killer cells, dendritic cells.
- Functions of some of these cells are:
- Macrophages hunt down pathogens and kill them in a process called phagocytosis.
- Mast cells play an important role in wound healing and defence against pathogens via the inflammatory response.
- Neutrophils are the first cells to arrive at the site of infection and can stop pathogens from proliferating. Pathogens also die when they come in contact with Neutrophils.
- Eosinophils can secrete a range of highly toxic proteins and free radicals that kill bacteria and parasites.
- Similar to mast cells, basophils are also key players in mounting an allergic response.
- Natural Killer cells (NK cells), do not attack pathogens directly instead, they destroy infected host cells in order to stop the spread of an infection.
- Dendritic Cells can identify threats and act as messengers for the rest of the immune system by antigen presentation.
Adaptive Immune System:
- This system is antigen specific and goes into action after the host has already been exposed to that particular antigen before.
- Cells of the adaptive immune system have immunological memories, which means they actually ‘remember’ a pathogen from its previous attack and thus have build up a response against it the next time that particular pathogen enters the body.
- The adaptive immune system consists mostly of lymphocytes, killer T cells, helper T cells, B lymphocytes and antibodies, immunological memory.
- Their functions are:
- Lymphocytes are a special type of leukocyte and consist of B cells and T cells which carry receptor molecules that recognize specific targets.
- Killer T cells are a sub-group of T cells responsible for killing cells that are infected with viruses (and other pathogens), or are otherwise damaged or dysfunctional.
- Helper T cells regulate both the innate and adaptive immune responses and help determine which immune responses the body makes to a particular pathogen.
- A B cell identifies pathogens when antibodies on its surface bind to a specific foreign antigen. Antibodies can also neutralize challenges directly, by binding to bacterial toxins or by interfering with the receptors that viruses and bacteria use to infect cells.
- When B cells and T cells are activated and begin to replicate, some of their type become long-lived memory cells which, throughout the lifetime of an animal, each specific pathogen encountered and can develop a strong response if that pathogen invades the body again.
Extract from HSC Biology Stage 6 Syllabus. © 2017 Board of Studies NSW.