Immune Response Flashcards
Why do we need to maintain our barriers between the external and internal environments?
We need to maintain the barrier between our internal and external environments.
The barrier keeps potential invaders out: bacteria, viruses, protozoans, and other parasites.
What are the bodies defences?
Impermeable epithelium, ridding mechanisms, inflammatory response, innate immunity, acquired immunity.
How is the epithelium impermeable?
adapted to function- the skin is waterproofed, multi-layered to resistant to wear and tear.
What are ridding mechanisms?
: vomiting, diarrhoea, coughing, sneezing. Vomiting and diarrhoea rid substances from the gut. May loose a lot of fluid so need to keep fluid balance up. Coughing and sneezing clear irritants and foreign material from the respiratory passages, however they do help to spread infections.
What is innate immunity?
Innate immunity is systems that are in place to defend the body without having to detect the invading organism. They are robust systems but not powerful against specific invading organisms.
The innate immunity approach is by blocking entry, or ingesting it if it does get in.
This process is called phagocytosis
What is phagocytosis?
the white blood cells that are adapted to do this essentially flow around and envelop the invading material, once it is contained within them they secrete enzymes that destroy whatever’s in there and so digest the product.
In this way they are the first line defence against infection and will also clean up any damaged cells and debris within the body. They act to prevent further damage or invasion and initiate the repair processes.
Is the innate immunity system specific of non-specific?
the innate immune response is non specific, it does not need to have seen the invader beforehand.
It acts through its barrier functions for example the impermeable skin through chemical means, by acid secretion in the stomach and other secretions on epithelial surfaces that inhibit microbes.
The initiation of an inflammatory response.
The production of other chemical agents and destruction by phagocytosis.
Where are white blood cells made and how do they travel around the body?
• White blood cells (also known as leukocytes) are formed in bone marrow or lymphatic tissue and transported around the body to where they are needed.
What are neutrophils and monocytes?
• Neutrophils are the most common white blood cells over 60% and Monocytes 5%, these are the main phagocytic cells of the innate immune system.
What are the features of acquired immunity?
Memory, specificity and recognition of self.
How does memory work in acquired immunity?
The acquired immune system needs to remember the characteristics of microbes it has already encountered.
All cells have surface proteins and glycoproteins that act as cell markers that identify cell type and where it’s come from.
These cell markers are called antigens
The acquired immune system recognises the shape of these proteins and glycoproteins.
Over time the acquired immunity system will collect a library of antigens it will recognise
What is specificity in the acquired immune system?
Specificity means that it recognises a particular antigen and not just an antigen like it.
The issue here is that if the antigen changes, the acquired immunity system wouldn’t recognise it and it would be like a new infection.
Why does the acquired immune system
The acquired immune system needs to recognise host cells so that it doesn’t attack its own cells.
The body does not want to attack its own cells, when it does this is called autoimmune disease.
What is humoral immunity?
The humoral response protects the fluid environment and is mediated through circulation.
In humoral immunity the B cells work by mainly secreting immunoglobulins, which are large proteins that recognise antigens. Each immunoglobulin is specific to a particular antigen.
They bind to the antigen and may also bind to other cells expressing the same antigen, making a clump of cells. They then attract macrophages to come and destroy what they have identified.
Immunoglobulins are also known as antibodies.
They circulate within the blood. If a specific antigen is detected, more of the antibody related to that antigen is produced.
What are some problems with the immune system?
Too much of an immune response e.g., hypersensitivity or allergy. IgE is particularly involved in this sort of response.
Too little immune response e.g., immune suppression can be done therapeutically e.g., when someone gets an organ transplant and you don’t want the body to react against the transplanted tissue.
The immune system may respond to the wrong target e.g., when the body mounts immune responses to its own tissue- an autoimmune disorder.
