Disease - Module 4 Flashcards
Process of phagocytosis
antigen presenting
1-6
1) Phagocyte attracted by chemicals produced by pathogen
2)phagocyte recognises pathogen as non-self and binds to it
3)phagocyte engulfs the pathogen to form phagosome - lysosome moves towards phagosome and combines with it, forming phagolysosome
4) In phagolysosome, enzymes break down the pathogen
5)digested pathogen absorbed by phagocyte - antigens combine with MHC in the cytoplasm
6)MHC/antigen complex is displayed on phagocyte membrane, making an antigen presenting cell
how do bacteria cause damage to host`?
Release Toxins which damage cell`
how do virusus damage the host?
Invade living cells, produce biochemical and structural changes in host cell. These can change cell functions or destroy the cell
How do protoctista enter host?
Parasites enter body through food or water contaminated by faeces of infected animal or person
how do Fungi damage host ?
IN plants, Fungi can digest plant tissue directly or through potent toxins
1)what is tuberculosis caused by?
2)Treatments
1)Bacteria
2)Antibodies, Improve living standards
1)what is Bacterial Meningitis caused by?
2)Treatments
1)Bacteria
2)Early antibiotics, Vaccines can prevent
1)what is HIV/AIDS caused by?
2)Treatments
1)Virus
2) Anti-retroviral drugs to slow down effects
1)what is Influenza caused by?
2)Treatments
1)Virus
2)Vaccine, antibiotics
1)what is Malaria caused by?
2)Treatments
1) Protoctista
2)Controlling mosquitos
1)what is Ring Worm caused by?
2)Treatments
1)Fungi
2)Antifungal creams
1)what is Ring Rot caused by?
2)Treatments
1) Gram positive bacteria
2)Wait for two years and destroy crops
1)what is Tobacco mosaic virus caused by?
2)Treatments
1) Virus
2)Resistant crop strains
1)what is Potato blight caused by?
2)Treatments
1) Protoctist
2)Resistant strains, careful management, chemical treatments
1)what is Black sigatoka caused by?
2)Treatments
1)Fungus
2) Resistant chains being developed, Fungicide
What signals the Production of Phytoalexins
-Pathogens can secrete cellulases to digest plant cell walls and enter the cells
-The products of cellulose hydrolysis are detected by receptors on the surface of the cell and signal to the cell that an attack is happening
*-The plant cell then produces phytoalexins as a defence mechanism
4 Roles of phytoalexins
-Disrupt cell membrane of bacteria
-stimulate ptoduction of chitinase to break down cell walls of fungal pathogens
-Disrupt metabolism of pathogen
-Delay reproduction of pathogen
4 Internal Plant defence
1) defensive chemicals give the alarm to other cells before they are attacked
2)Polysaccharides made to strengthen the cell walls (callose + lignin)
3)Signalling molecules alert nucleus to attack
4) phytoalexins
5 types of non-specific immune response
-Skin
-Mucous Membranes
-Lysozymes
-Expulsive Reflexes
-Blood clotting and wound repair
Skin in the non-specific immune response
- covers body to prevent entry of pathogens
-Healthy microbes live on skin and out compete pathogens
-when we sweat, salt changes the PH and prevent microbes producing
Mucous Membranes in the non-specific immune response
-Line body tracts
-contain goblet cells which secrete sticky mucus
-mucus also contains phagocytes
Lysozymes in the non-specific immune response
-Found in blood, sweat and tears
-Catalyses the breakdown of microbial cell walls
Expulsive reflexes in non-specific immune response
-coughs and sneezes remove mucus (and trapped pathogens) from airways
-vomiting and diarrhoea remove pathogen from gut
Blood Clotting and wound repair in the non-specific immune response
basic
-Platelets adhere to collagen in the skin or cell wall of the damaged vessel
-This triggers the secretion of thromboplastin and seratonin
Inflammatory response. Mast cells, Histamines and Cytokines
Localised response to pathogens resulting in inflammation
Characterised by pain, heat, redness and swelling.
Mast cells are activated in damaged tissues and release chemicals called histamine and cytokines
Histamines
Make the blood vessels dilate, causes localised heat and redness. Raised temperature helps prevent pathogens reproducing.
Make blood vessel walls more permeable so blood plasma is forced out. This is then known as tissue fluid. This causes swelling and pain.
Cytokines
Signal white blood cells to the site.
Process of blood clotting
-Platelets activated by damaged tissue
-release thromboplastin (enzyme)
-This catalyses reaction of prothrimbin into thrombin
-Ca 2+ ion needs to be present
-thrombin (enzyme) catalyses reaction of Fibrinogen into fibrin
-Fibrin forms the clot
Process Fever
why is it useful
Normal body temperature is maintained by the hypothalamus in the brain.
Cytokines stimulate the hypothalamus to raise the temperature of the body
This is useful because:
Most pathogens reproduce best at 37oC or lower. Higher temperatures inhibit pathogen reproduction.
The specific immune system works faster at higher temperatures.
Phagosome
the vesicle a pathogen is engulfed by
Neutrophil
a short-lived phagocytic cell which makes up 60-70% of phagocytes
Macrophage
a large long-lived phagocytic cell found in tissue