cells and the immune system Flashcards
Each type of cell has ________ molecules on its ________ that identify
it.
Each type of cell has specific molecules on its surface that identify
it.
Antigens
-molecules that can generate an immune response when detected by the body
-found on the surafce of cells
-_ antigens that aren’t usually found in the body are forgein anitgens/ allow idetification of celg molecules and non-self molecules
-it is the specific 3d structure that distinguishes one cell from another.
antigens allow the immune system to identify
pathogens- all have antigens on their surface. which can be identified as foreign and destroyed
toxins- Are poisons. molecules not cells. is the antigen produces by bacteria. Immune system can respond to toxins and the pathogen that released them.
abnormal body cells- cancerous or pathogen-infected cells have abnormal antigens on surface triggers an immune response.
Cells from other organism of the same species/non-self material- cells reicved from anothrt person e.g transplant or blood transfusion. will have some antigens that are differnt from the recipient. foreign antigen trigger immune response.This can lead to rejection if immunosuppressant drugs aren’t taken.
Immune response
antigen—->immune response——> Immediate= non-specific (e.g phagocytosis,inflammation, antimicrobial proteins).———->delayed=specific (B cells, T cells)
Non-specific immune responses
-Fever
-inflammation
-interferon
-phagocytosis
-histamines
Histamines
-released by most cells/damaged white blood cells.
-cause blood vessles to dialate cause local heat and redness
-higher temp prevents pathogen from reproducing
-blood vessles more leaky,plasma forced out causing pain and swelling.
E.g hayfever- antigrn such as pollen = allergic response, histmine is relase. antihistamine reduce allergic response histmaine and is simular shape to antihistamine so antihistmine bind to histamine recpectore and prevent the histamine binding
Inflammation
-ofteninfection localised at one sight
-when tissue damaged white blood cells relase histamine, aterioles become leaky
-more wide spread= rash
inteferon
-produced by Cells infected by viruses anti-viral proteins called interferons
-Interferons prevent viruses from spreading to uninfected cells, bind to repetors of unaffected cells
-They inhibit the production of viral proteins, preventing the virus from replicating
-They activate white blood cells involved with the specific immune response to destroy infected cells-they increase the non-specific immune response e.g. by promoting inflammatio
Fever
-raise in body temperature
-helps kill pathogens prevents them reproducing
-specific response=better at a higher temp
lysozymes
-enzymes in tears saliva , nasal secretions
-kills bacteria by breaking down cell walls
a phagocyte (e.g a macrophage) is a type of ——– blood cell that carries out __________.found in blood and tissues and are first to respond to immune system trigger inside the body.
a phagocyte (e.g a macrophage) is a type of white blood cell that carries out phagocytosis.found in blood and tissues and are first to respond to immune system trigger inside the body.
steps phagocytosis
1)phagocyte recognises foreign antigens on pathogen
2)cytoplasm of the phagocyte moves around the pathogen engulfing it
3)The pathogen is now contained in the phagocytic vacuole in the cytoplasm of the
4)a lysosome fuses with the phagocytic vacuole and the lysosymes break down the pathogens.
5)the phagocyte presents the pathogens antigens-it sticks them to it’s surface to activate other immune systems cells. The phagocyte is acting as a antigen-presenting cell.
Types of white blood cells
neutrophils (70%)
lymphocytes (24%)
Monocytes (4%)
other white cells (2%)
neutrophils
(phagocytes)
-leave blood capillaries by squeezing between cells
-ingest and and destroy bacteria
-80 million produce a minute and last a few days.
lymphocyte
two types-B cells and T cells
-involved in immune response, including antibody production and immunity
-some last a few days others a few years
