Communicable diseases

communicable diseases

diseases caused by pathogens which can be transmitted between organisms

pathogen

microorganisms that cause disease

bacteria

single-celled organisms that lack a nucleus; prokaryotes

toxins

Various poisonous substances produced by some microorganisms (bacteria and viruses).

fungi

A kingdom made up of nongreen, eukaryotic organisms that have no means of movement, reproduce by using spores, and get food by breaking down substances in their surroundings and absorbing the nutrients

spores

single-celled reproductive bodies highly resistant to cold and heat damage; capable of new organisms/spreading disease - can be transported through contact, water and air

saprophytic

relationship in which an organism obtains its nourishment from dead organic matter

parasitic

type of relationship where one organism survives by harming a host organism

virus

A tiny, nonliving particle that invades and then reproduces inside a living cell.

Protists

single-celled or simple multicellular eukaryotic organisms that generally do not fit in any other kingdom - can cause disease

tuberculosis

An infectious disease that may affect almost all tissues of the body, especially the lungs

bacterial meningitis

inflammation of the protective membranes covering the brain and spinal cord caused by various types of bacteria

ring rot

A bacterial disease in tomatoes, potatoes and aubergines that results in damage to the leaves, fruit and tubers. It is caused by the Clavibacter michiganensis bacterium.

HIV

A virus that attacks and destroys the human immune system.

AIDS

A serious (often fatal) disease of the immune system transmitted through blood products especially by sexual contact or contaminated needles.

influenza

flu virus

tobacco mosaic virus

Virus that causes discolouring in tobacco leaves by preventing the formation of chloroplasts. It was the first virus ever discovered.

black sigatoka

Fungus which affects banana plants

blight

(n.) a disease that causes plants to wither and die; a condition of disease or ruin; (v.) to destroy, ruin

ringworm

A highly contagious, fungal infection of the skin or scalp.

athlete's foot

Fungus infection usually in the skin of the toes and soles

malaria

A disease caused by mosquitoes implanting parasites in the blood.

transmission

Transfer, such as of a disease, from one person to another

direct transmission

Transmission of blood or body fluids through touching (including shaking hands), kissing, coughing, sneezing, and talking.

direct contact

Touching or contact with a patient's blood or saliva

inoculation

transmission of disease through a break in the skin, e,g during sex, an animal bite, a puncture wound or sharing needles

ingestion

the transmission of disease by taking in contaminated food or drink or touching your mouth

indirect transmission

Transmission of blood or body fluids through contact with an intermediate contaminated object such as a razor, extractor, nipper, or an environmental surface.

fomites

objects contaminated with infectious material that contains the pathogens

droplet infection

A disease that results from contamination with water-based microorganisms

vectors

An organism that transmits disease by conveying pathogens from one host to another

soil contamination

soil that has been in contact with a pathogen and can still pass it on

passive defense

defenses against pathogends which are present before infection

phytoalexins

an antibiotic, produced by plants, that destroys microorganisms or inhibits their growth

PR proteins

pathogenesis-related proteins; protein involved in plant responses to pathogens

systemic acquired resistance

A defensive response in infected plants that helps protect healthy tissue from pathogenic invasion.

salicylic acid

A plant hormone that may be partially responsible for activating systemic acquired resistance to pathogens.

tylose formation

a balloon like swelling or projection that fills the xylem vessel. When it is fully formed, it plugs the vessel and water can no longer be transported.

waxy cuticle

forms a waterproof layer to prevent water collecting on cell surfaces - pathogens need water to survive

stomatal closures

can prevent entry when a pathogen is detected in the air

bark

a hard outer covering of a tree which contains chemicals that work against pathogens

lignin

complex polymer that hardens cell walls of some vascular tissues in plants

callose

A large polysaccharide deposit that blocks old phloem sieve tubes

terpenoids

Range of essential oils that have antibacterial and antifungal properties

defensive proteins (defensins)

proteins which have anti-microbial activity, they disrupt molecules in the plasma membrane of pathogens, possible inhibiting the action of ion transport channels

alkaloids

nitrogen-containing compounds, they have a bitter taste, which inhibits herbivory, they interrupt metabolic reactions by inhibiting or activating enzyme action

hydrolytic enzymes

found in the spaces between cells, include chitinases, glucanases and lysozymes

phenols

have antibiotic and antifungal properties, tanins bind to salivary proteins and digestive enzymes, deactivating the enzymes

tanins

astringent, repels herbivores

necrosis

deliberate cell suicide in order to prevent a pthogen from spreading through the plant

canker

a sunken necrotic lesion in the woody tissue, causes death of the cambium tissue in the bark

mucous membrane

Membrane that secretes mucus that lubricates the surface of organs and keeps them moist.

lysozymes

An enzyme, present in mucus, tears, and saliva, that destroys bacteria by dissolving their cell walls.

expulsive reflexes

Coughing and sneezing, vomitting and diarrhoea as an attempt to expel foreign objects.
Occur automatically

blood clots

form around injury site to prevent any microbes or their toxins from spreading

clotting factors

proteins in the plasma that serve to activate various parts of the blood clotting process by being transformed from inactive to active forms. Also known as coagulation factors.

platelets

part of the formed elements of the blood; play a vital role in blood clotting

cell signalling

Processes that lead to communication and coordination between cells. Hormones binding to their receptors on the cell surface membrane are an example.

prothrombin

a protein present in blood plasma that is converted into active thrombin during coagulation.

thromboplastin

substance present in tissues, platelets, and leukocytes that is necessary for coagulation

thrombin

an enzyme in blood plasma that causes the clotting of blood by converting fibrinogen to fibrin.

fibrinogen

plasma protein that is converted to fibrin in the clotting process

fibrin

an insoluble protein formed from fibrinogen during the clotting of blood. It forms a fibrous mesh that impedes the flow of blood.

inflammation

a localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection.

histamines

Chemical substances released by the immune system when damage occurs, they cause vasodilation, make blood vessels more permeable and raise the body's temp in the damaged area

cytokines

Chemicals released by the immune system communicate with the brain, they attract phagocytes

vasodilation

widening of blood vessels

secondary defenses

protective processes which fight pathogens that have entered the organism

non-specific immune response

Any type of pathogen or foreign cell destroyed. Immediate response. Involves wbc called phagocytes.

phagocytes

a type of cell within the body capable of engulfing and absorbing bacteria and other small cells and particles.

neutrophils

A type of white blood cell that engulfs invading microbes and contributes to the nonspecific defenses of the body against disease.

macrophages

Found within the lymph nodes, they are phagocytes that destroy bacteria, cancer cells, and other foreign matter in the lymphatic stream.

chemotaxis

Cell movement that occurs in response to chemical stimulus

lysosomes

cell organelle filled with enzymes needed to break down certain materials in the cell including engulfed pathogens in phagocytes

phagosome

Intracellular vesicle containing material taken up by phagocytosis.

lysins

Enzymes used by phagocytes to digest engulfed bacteria

antigen presenting cells

Cells that display foreign antigens on their surface after engulfing them to initiate an immune response in the body

dendritic cells

specialized white blood cells that patrol the body searching for antigens that produce infections

opsonins

chemicals that bind to pathogens and tag them so they are recognised more easily by phagocytes, e.g. antibodies.

antibodies

Proteins that attach to antigens, keeping them from harming the body/joins them together to make phagocytosis easier

agglutinins

antibodies which join antigens/pathogens together to make phafocytosis easier

immunoglobulins

(antibodies) bind with specific antigens in the antigen-antibody response

specific immune response

Collection of several immunological events in which lymphocytes recognize the presence of a particular antigen and act to eliminate it.

active/acquired immunity

a form of immunity where the body makes antibodies against a particular disease

humoral response

The branch of acquired immunity that involves the activation of B cells and that leads to the production of antibodies, which defend against bacteria and viruses in body fluids.

B lymphocytes

form in the bone marrow and release antibodies that fight bacterial infections

plasma cells

Cells that develop from B cells and produce antibodies.

B memory cells

B lymphocytes that live a long time and provide immunological memory of the antibody needed against a specific antigen.

antigens

a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.

clonal selection

The process by which an antigen selectively binds to and activates only those lymphocytes bearing receptors specific for the antigen. The selected lymphocytes proliferate and differentiate into a clone of effector cells and a clone of memory cells specific for the stimulating antigen.

B effector cells

B lymphocytes that divide to form plasma cell clones

interleukins

play multiple roles in the immune system, including directing B and T cells to divide and proliferate

clonal expansion

the rapid multiplication of B or T cell clones after activation by an antigen

cell-mediated response

The branch of acquired immunity that involves the activation of cytotoxic T cells, which defend against infected cells.

T helper cells

T cells that are stimulated by antigen to provide signals that promote immune responses

T memory cells

T lymphocytes that live a long time and are part of the immunological memory.

T killer cells

T lymphocytes that destroy pathogens carrying a specific antigen with perforin.

T regulator cells

T lymphocytes that suppress and control the immune system, stopping the response once a pathogen has been destroyed and preventing an autoimmune response.

perforins

proteins that poke holes in pathogens and allow toxins to enter

autoimmune disease

a condition in which the immune system mistakenly attacks itself, targeting the cells, tissues, and organs of a person's own body