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4.1 Communicable Diseases - Coggle Diagram
4.1 Communicable Diseases
Organisms that cause disease
Bacteria
Belong to the kingdom Prokaryotae. Cells are smaller than eukaryotic but reproduce rapidly Once bacteria enter host they multiply rapidly. Presence cause damaging cells or releasing waste products or toxins toxic to host.
Viruses
Invade cells and take over genetic machinery and other organelles, Then cause cell to manufacture more viruses. Host cell eventually bursts releasing new viruses which infect healthy cells.
Fungi
Cause variety of diseases in both plants and animals. Common fungal infections where fungus lives in skin of animals where hyphae form a mycelium grow under skin surface. Causes redness and irritation.
Protoctista
Enter host cells and feed on contents as they grow.
Diseases
Tuberculosis
Kills cells and tissue; lung often affected
Bacteria
Bacterial Meningitis
Infection of the meninges, may cause damage to the brain and nerves
Bacteria
Ring Rot
Ring of decay in vascular tissue of potato tuber or tomato
Bacterium
HIV/AIDS
Attacks cells in immune system and compromises the immune response
Virus
Influenza
Attacks respiratory system causes muscle pains and headaches.
Virus
Tobacco Mosaic Virus
Causes mottling and discolouration of leaves.
Virus
Black Sigatoka
Causes leaf spots on banana plants reducing yield
fungus
Blight
Affects leaves and potato tubers
Protoctistan
Ringworm
growth of fungus in skin with spore cases erupting to cause rash
fungus
Athlete's Foot
growth under skin of feet
fungus
Malaria
Parasite in the blood causes headache and fever may progress to coma and death.
Protoctistan
Transmission of pathogens
Direct Physical Contact
Faecal - Oral transmission
Droplet Infection
Transmission by spores
Vaccination
Provides immunity to specific diseases by injecting antigenic material and treating like it's the actual pathogen.
The antigenic material can take a variety of forms:
Whole, live microorganisms not as harmful as the real disease.
Harmless or weakened version of the pathogenic organism.
Dead pathogen
Preparation of antigens from a pathogen
A toxoid, harmless version of a toxin
Application of Vaccines
Herd Vaccination
Provide immunity to almost or all population at risk. Once enough people are immune disease can't spread through the population.
Ring Vaccination
A new case of disease is reported. Vaccinate all people in immediate vicinity of new cases.
Defences against disease
Plant Defences
Passive Defences
Physical Defences
Cellulose Cell Wall
Physical Barrier as well as chemical defences as well.
Lignin Thickening
Waterproof and almost completely indigestible
Waxy Cuticles
Prevent water from collecting on cell surfaces. Due to pathogens collecting in water less water means less chance of pathogens entering cell.
Bark
Contains a variety of chemical defences that work against pathogenic organisms.
Stomatal Closure
Stomata closes so pathogens can't get in when detected by guard cells of stomata
Callose
Blocks the flow in the sieve tube prevents pathogen spread.
Tylose formation
Swelling to block xylem vessels so pathogens can't spread through the heartwood.
Chemical Defences
Plant tissues contain a variety of chemicals with anti pathogenic properties. Terpeniods, Phenols, Alkaloids and Hydrolytic Enzymes
Some chemicals prevent before infection, many chemicals though are not produced until a pathogen is detected.
Active Defences
Cells become thickened and strengthened with additional cellulose.
Deposition of callose impede cellular penetration. Strengthens the wall and blocks plasmodesmata.
Oxidative Bursts produce highly reactive oxygen capable of damaging cells of invading organisms.
Increase in chemical production
Primary Defences Against Diseases
The Skin
Main primary defence. Outer layer of skin is epidermis and consists of layers of cells. Most cells are called keratinocytes and are produced my mitosis at base of epidermis. Migrate out to surface of skin as they migrate they dry out and cytoplasm is replaced by keratin. This is keratinisation and takes about 30 days.
Blood Clotting and Skin Repair
Mucous Membranes
Coughing and Sneezing
Inflammation
Immune Response
Cells produced in immune response
T helper cells - stimulate B cells to develop phagocytosis by phagocytes.
T killer cells - Attack and kill host body cells displaying foreign antigen
T memory cells - Provide long term immunity
T regulator cells - Shut down immune response after pathogen is removed. Involved in preventing autoimmunity.
B memory cells - Remain in the body for years act as immunological memory
Cell Signalling
Communication is achieved through release of cytokines. Macrophages release monokines and attract neutophils, others stimulate B cells to release antibodies. T cells and macrophages release interleukins stimulate clonal expansion. Many cells can release interferon which stimulates activity of T killer cells.
Autoimmune Diseases
When immune system attacks a part of the body. Arises from antibodies attacking own antigens because antigens are not normally exposed to attack become exposed.