Immunity

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What are the 2 forms of non-specific mechanims?
1. a barrier to the entry of pathogens 2. phagocytosis
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What are the 2 forms of specific mechanisms?
1. Cell mediated responses involving T lymphocytes. 2. Humoral responses involving B lymphocytes
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What is the difference between non specific and specific mechanisms?
Non specific response is immediate and the same for all pathogens. Specific- the response is slower and specific to each pathogen
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What is a pathogen?
Organisms that cause disease
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What are the 3 types of pathogens?
bacteria/virus/fungi
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Describe the process of phagocytosis?
1. Pathogen produces chemical products which attract the phagocyte to the pathogen (chemotaxis). 2. Phagocytes attach themselves to surface of pathogen. 3. Phagocytes engulf pathogen via a vesicle(a phagosome).4. lysosomes fuse with phagosome.
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The process of phagocytosis continued
Enzymes digest the pathogen by hydrolysing large molecules. 6. soluble products of digestion absorbed into phagocyte cytoplasm.7.some of the pathogens antigens remain in phagocytes cell membrane.
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What is an antigen?
An antigen is any part of an organism or substance that is recognised as non-self by the immune system and stimulates a response
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What is cell mediated immunity?
It is where T lymphocytes will only respond to antigens that are attached to a body cell rather than to antigens within the body fluids
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Explain the stages in the response of T lymphocytes to infection by a pathogen?
1. Pathogens invade body cellsor are taken in by phagocytes. 2. The phagocyte places antigens from the pathogen on its cell surface membrane. 3. Receptors on certain T helper cells fit exactly onto these antigens.
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The process of T lymphocytes response continued
4. This activates other T cells to divide rapidly by mitosis and form a clone.5.The cloned T cells 1.develop into memory cells that enable a rapid response to future infections by same pathogen
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How do T cells kill infected body cells?
They produce a protein that makes holes in the cell surface membrane. These holes mean the cell becomes freely permeable to all substances and dies as a result.
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What is MMR?
It is a safe and effective combined vaccine that protects against 3 separate illnesses-measles,mumps and rubella.
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What is tuberculosis?
It is a bacterial infection spread through inhaling tiny droplets from the coughs or sneezes of an infected person
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What are the symptoms of TB?
Weight loss/night sweats/high temperature/tiredness and fatigue/loss of appetite.
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What is a vaccine?
A vaccine is adding a substance to the body to stimulate active immunity against a disease.
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What is herd immunity?
Its when a large proportion of the population have been vaccinated to make it difficult for a pathogen to spread within that population. Individuals are protected.
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Why is herd immunity important?
Because it is never possible to vaccinate everyone in a large population. For example, babies and very young children.
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Describe the effects of the formation of an antibody-antigen complex?
Agglutination of antigens/ Immobilises microbes/ Blocks active region of toxin so it is harmless/ Prepare complex for ingestion by phagocytosis
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Card 2

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What are the 2 forms of specific mechanisms?

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1. Cell mediated responses involving T lymphocytes. 2. Humoral responses involving B lymphocytes

Card 3

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What is the difference between non specific and specific mechanisms?

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Card 4

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What is a pathogen?

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Preview of the front of card 4

Card 5

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What are the 3 types of pathogens?

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