Diseases and the Immune system Flashcards
what is a disease
condition that impairs the normal functioning of an organism
what are the types of pathogen
- bacteria
- proctista
- virus
- fungi
what are the types of bacteria
Cocci
- small surface area to volume ratio
- survive in dry conditions
- cause acne
Bacilli
- large surface area and take up nutrients
- causes food poisoning
Vibrio
- large surface are and takes up nutrients
- causes cholera
Spirillum
- corkscrew motion
- stomach ulcers
how do bacteria reproduce
- chromosomes duplicate
- cells grows
- cell divides into two
quick reproduction can cause spoiled food and spread disease
how do bacteria cause disease
- antigen on bacterium
- produce toxins
- damage cell membranes, enzymes, genetic material
what are the bacterial diseases
Tuberculosis
- caused by droplet infection
- dry cough, fever, fatigue, weight loss
Bacterial meningitis
- spread or respiratory and throat secretions
- fever, vomiting
Ring Rot
- discolouration
- leaf curling
what is protoctista
- unicellular
- nucleus
what is plasmodium
- live as a parasite inside a female mosquito
- mosquito secretes saliva into bloodstream that contains sporozoites
- attack liver cells
- merozoites reproduced asexually and attack red blood cells
- maturation and production of parasites
- female mosquito pregnant with parasite
- infects human
what are the protozoan diseases
Blight in potatoes/tomatoes
- fungus like organism that spreads rapidly through potato in warm wet conditions
- leaves collapse, shrivel, turn brown
Malaria
- caused by a parasite
- fever, chills, discomfort, headache, nausea
Bacteriophage
- attaches to a specific host cell
- injects genetic material into the host cell
- viral gene causes the host cell to reproduce new viruses
- host cell splits open to release the new virus and the process repeats
what is retrovirus replication
- virus attaches to the host cell
- virus fuses with cell surface membrane and enters cell by endocytosis
- virus injects RNA
- RNA used as a template to make DNA
- DNA inserted into chromosomes by protein integrase
- viral RNA synthesised by host cell by transcriptase
- leaves nucleus and cell
what are viral diseases
HIV/AIDS
- sexually transmitted
- fever, night sweats, weight loss
Influenza
- droplet inflection
- fever, aching, dry cough, sore throat
Tobacco mosaic virus
- direct contact with plants
- reduce crop yield, yellow spotting, mosaic pattern, malformation
what are fungal diseases
Cattle ringworm
- infection of hair and surface layers of the skin
- itchy skin, cracked skin, hair loss
Athlete’s foot
- fungi living on skin, hair, nails called dermophytes that favour warm humid conditions
- sore flaky patches, blisters, itchy skin
Black sigatoka
- airborne
- streaks or leaf spots
what is indirect transmission
Fomites
- inanimate objects
- bedding, socks
Vectors
what is indirect transmission
Direct Contact
- contact with bodily fluids
- skin to skin
Inoculation
- break in the skin
- puncture wound
Ingestion
Droplet infection
what are factors that increase the transmission of communicable diseases in animals
- overcrowded populations
- poor waste disposal
- compromised immune system
- culture
- climate change
what are primary defences
Blood clotting = thromboplastin causes blood to clot
Skin = produces sebum that inhibits the growth of pathogens
Expulsive reflexes = coughing and sneezing
Nose = hair and mucus trap and destroy microbes
Eye = tears and REM
Ear = ear wax traps pathogens
Cilia = trap microbes and swallowed
Eating = stomach acid kills microbes
types of phagocytes
Neutophils
- lobed nucleus
- engulf and destroy pathogens
Macrophages
- round nucleus
- pathogens antigens combined with glycoproteins to make the antigen and antigen presenting cell
what are non-specific defences
Inflammation
- damaged tissues release histamines to make vessels dilate and leaky
- prevents pathogens from reproducing
what is phagocytosis
- phagocyte recognises antigens of invading bacterium as foreign
- cell membrane of the phagocyte fuses around the bacterium and engulfs it
- lysosome fuses with vacuole and digestive enzymes hydrolyse microorganisms
- antigens presented on cell surface membrane
what is cellular immunity by T Lymphocytes
- surface covered with receptors
- receptors bind to antigens
- receptor on T lymphocyte meets complementary antigen
- activates T-Lymphocyte (clonal selection)
- matures in bone marrow
- clonal expansion (clones of plasma and memory cells)
what is humoral immunity by B lymphocytes
- covered with antibodies
- antibodies bind with antigen to form antigen-antibody complex
- antibody on the surface of a B-lymphocyte meets and complementary antigen binds
- helper t cell release interleukins to activate B lymphocytes
- clonal expansion
what are the types of T-Lymphocytes
T Helper Cells
- secrete interleukins to activate T and B cells
T regulatory cells
- supress immune response from attacking host cells
T memory cells
- remain in lymph nodes to respond rapidly if the same pathogen invades again
Killer T cells
- protein binds to non-self antigen
- perforin released
- foreign cell identified
- lysis
- non-self cell splits and destroyed
what are the types of antibodies
Opsonin’s
- bind to antigen and act as a marker for phagocytes
Agglutin’s
- bind to antigens to cause clumping to prevent them from entering body cells
Anti-Toxins
- bind to toxins to prevent harm
