disease

Created by

Molly Littlewood

Cards (72)

bacteria - prokaryotic cells, no nucleus, no membrane bound organelles
viruses - are not living organisms, they are made up of nucleic acids and protein coat, cause the cell to manufacture more copies of the virus and the cell will lyse releasing the new virus
protoctista - single celled eukaryotes that are not plant or animal cells
fungi - eukaryotic organisms that reproduce through spores, many are saprophytes (secrete enzymes onto matter)
tuberculosis
bacteria
affects cows and humans
droplet infection
antibiotic treatment
vaccination prevention
bacterial meningitis
bacteria
affects humans
droplet infection
antibiotic treament
vaccination prevention
hiv/aids
virus
affects humans
bodily fluid transmission
anti-retroviral drug treatment
education = prevention
influenza
virus
affects humans and birds
droplet infection and indirectly through touching surfaces
treatment = rest
vaccination = prevention
athletes foot
fungus
affects humans
direct transmission
treatment is antifungal creams
keeping skin clean is prevention
ring worm
fungus
affects humans and cows
direct transmission
anti fungal treatment
ventilation is prevention
malaria
protoctista
affects humans
vector - mosquitoes
antimalarial medication
removing standing water is prevention
ring rot
bacteria
affects potatoes and tomatoes
either direct (touching) or indirect (contaminated equipment) transmission
destroy infected plants
sanitise equipment = prevention
tobacco mosaic virus
virus
affects tomatoes and and tobacco
direct or indirect contact
burn all diseased plants
sanitise equipment = prevention
potato late blight
protoctist
affects potatoes and tomatoes
direct and indirect transmission
no cure
burn infected plats and use resistant strains
black Sigatoka
fungus
affects bananas
direct and indirect transmission
fungicide treatment can control spread but no cure
remove diseased leaves as prevention
direct transmission between animals
direct contact - kissing any contact with fluids
ingestion - eating contaminated food and drink
inoculation - through a break in the skin e.g, malaria
indirect transmission between animals
droplet infection - e.g., influenza, tuberculosis
formites - inanimate objects such as bedding and towels can transfer pathogens e.g, athletes foot
vectors - transmits pathogen from host to host e.g., malaria
transmission between animals and humans - some diseases can be passed not as a vector, but as a direct contact
e.g., bird flu, rabies from dogs
factors affecting transmission in animals
overcrowding
poor nutrition
compromised immune systems
poor disposal of waste
climate change
infrastructure
sanitation
transmission between plants
direct contact - a healthy plant touches any part of a diseased plants
e.g., tobacco mosaic virus, potato late blight
indirect transmission between plants
soil contamination - pathogens can remain in the soil e.g., tmv
wind - spores can be carried in the wind, e.g., black Sigatoka
water - spores can swim on the surface of water e.g., potato late blight
vector animal - insects and birds carry pathogens from plants when they feed, can inoculate the pathogen into the plant
vector human - pathogens can be transmitted by hands and tools
factors affecting transmission in plants
planting varieties of crops that are susceptible to disease
over crowing
poor mineral nutrition
damp warm conditions
climate change
plant defences against pathogens - physical defences
cellulose cell wall
lignin - thickens cell wall and is waterproof
waxy cuticle - prevents water collecting on
bark - contains chemical defences
stomatal closure - guard cells close stomata
tylose - xylem parenchyma cells which blocks pits
callose - blocks sieve tube elements
leaf drop
chemical defences by plants
toxins
insect repellents - lemongrass and citronella
antibacterial - antibiotics that can kill bacteria
insecticides - reduces insect vectors
anti fungal - hydrolytic chitinase enzymes breakdown chitin in fungi walls
skin - primary non specific defence
contains fibrous keratin
physical barrier to pathogens
produces sebum which is an oily substance that pathogens cannot stick to
mucous membranes - primary non specific defence
goblet cells in epithelium secrete mucus
pathogens are trapped in mucus
cilia waft the trapped pathogens
expulsive reflexes - primary non specific defence
expel pathogens from the body
e.g., cough, sneeze
blood clotting - primary non specific defence
damage to blood vessel exposes collagen and releases clotting factors
clotting factors from the damage to blood vessel wall and from the binding of the platelets activate the enzyme thromboplastin
active thromboplastin uses calcium ions as a cofactor to change prothrombin into thrombin (enzyme)
thrombin converts soluble fibrinogen into insoluble fibrin
fibrin traps red blood cells and causes fibres to attach to the platelet plug
a clot is formed
wound repair - primary non specific defence
blood clots seal the wound to prevent entry of microbes
serotonin is released as well as clotting factors causing the blood vessel walls to contract, reducing blood flow to the area (avoid blood loss)
once the clot has formed a scab is formed, the scab shrinks as it dries drawing the sides of the cut together
the deposition of collagen under the scab and then stem cells in the epidermis undergo mitosis
new blood vessels grow to supply oxygen to the tissues
once the skin is complete the scab is released
inflammation - non specific defence
inflammation is heat, pain, and swelling
the presence of microbes in the tissue is detected by mast cells
these cells release histamines and cytokines
histamine causes vasodilation making capillary walls more permeable to white blood cells causing an increase in tissue fluid and therefore swelling
the excess tissue fluid drains into the lymphatic system where pathogens are engulfed by lymphocytes
cytokines attract phagocytes to the area where pathogens can be removed by phagocytosis
fevers - non specific defence
cytokines stimulate the hypothalamus to rest the internal thermostat
higher temps inhibit pathogen reproduction
immune system works faster at higher temps
neutrophils
phagocyte
60% of white blood cells
squeeze through capillaries in tissues
first defenders
short lived
macrophages
phagocyte
larger cells
they leave bone marrow and travel in blood as a monocyte, once out of the blood become a macrophage
long lived cells - antigen presenting cells
cytokines - cell signalling molecules, increase body temperature, attract phagocytes
antigens - molecules made up of glycoproteins that allow the body to recognise 'self'
opsonins - chemicals that bind to pathogens, bind to antigens on the pathogen, phagocytes have receptors for opsonins on their cell membranes. antibodies can be opsonins
phagocytosis - non specific (neutrophils)
opsonins attach to antigens on pathogen (opsonisation)
receptors on the neutrophil attache o opsonins on the pathogen
neutrophils engulf the pathogen in a phagosome
lysosomes fuse creating a phagolysosome
hydrolytic enzymes digest the bacterium
stage 1 antigen presentation - the specific immune response
antigen on pathogen binds to receptor on macrophage
pathogen engulfed by phagocytosis and forms a phagosome
lysosomes fuse forming a phagolysosome
pathogen is partially digested by hydrolytic enzymes
fragments of the antigen are placed on the surface, the macrophage is now called an antigen presenting cell
indigestible material is removed by exocytosis
stage 2 t lymphocyte activation - cell mediated immunity
antigen presentation, macrophage engulfs and processes and presents the antigen together with a self protein
clonal selection - each t lymphocyte has a complementary receptor, the macrophage releases cytokines that activate the specific t lymphocyte
clonal expansion - the activated t lymphocyte divides many times by mitosis
t lymphocyte
made in bone marrow and mature in thymus gland
only recognise antigen if together with self protein - e.g., antigen presenting cell