C3.2 Defence against disease | Quizlet

skin

forms a dry barrier that prevents the entry of most pathogens

pathogen

an organism or virus that causes a transmissible disease

mucous membrane (mucosa)

a moist surface layer that prevents entry of pathogens to the body

blood clotting

a mechanism to prevent entry of pathogens to the bloodstream after damage to a blood vessel

Fibrinogen

the soluble blood protein that is converted to fibrin to form a blood clot

platelets

cell fragments involved in blood clotting process

thrombin

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

phagocytes

type of blood cell that engulfs foreign particles and cells (viruses and bacteria)

B lymphocytes (B cells)

type of white blood cell that makes a specific antibody to fight infections by a specific pathogen

immunity

the presence in the blood of B and helper T memory cells to a specific pathogen which was established through natural exposure to the pathogen or vaccination

natural passive immunity

the immunity given to an infant mammal by the mother through the placenta and the colostrum.

antibody

A protein that binds to a specific antigen; produced by specific lymphocytes in response to exposure to that antigen

artificial passive immunity

immunity which results from the injection of antibodies to a specific pathogen that were made in another animal.

antigen

substance that triggers an immune response; the production of antibodies

antibiotic

A chemical that kills bacteria or slows their growth by inhibiting a specific prokaryotic metabolic pathway.

virus

a particle made of an outer protein coat containing DNA or RNA that can infect living cells and replicate inside them

bacterium

a microscopic prokaryote. Some are pathogens

fungus

(usually) microscopic eukaryote with cell walls; some are pathogens

protist

A eukaryotic organism that cannot be classified as an animal, plant, or fungus; some single celled species are pathogenic

HIV

A virus that invades human helper T lymphocytes and causes a reduced ability to produce antibodies to other infections

prothrombin

plasma protein; converted to thrombin in the clotting process

clotting factors

plasma proteins that activate various parts of the blood clotting process by being transformed from inactive to active forms.

Lysozyme

enzyme found in saliva, sweat and tears that destroys the cell walls of certain bacteria

Helper T lymphocyte

type of white blood cell that activates B cells which then secrete antibodies

Macrophages

Amoeboid cells that roam through tissues and engulf foreign particles / cells; then present antigens on their surface.

phagosome

vesicle formed as a result of phagocytosis

lysosome

An organelle containing digestive enzymes

Zoonosis

An infectious disease that is transmissible from (vertebrate) animals to humans.

Herd immunity

The resistance of a group to the spread of a transmissible disease because a large proportion of the members of the group are immune; either through natural infection or vaccination

Pandemic

an epidemic that is geographically widespread (many countries / continents)

epidemic

a widespread occurrence of an infectious disease in a community at a particular time.

innate immune response

rapid but relatively nonspecific immune response that is the similar for every pathogen

adaptive immune response

The response of antigen-specific B and T lymphocytes to antigen, including the development of memory cells

memory cells

a long-lived lymphocyte (B or T cell) capable of responding to a particular antigen on its reintroduction, long after the exposure that prompted its production.

antibiotic resistant bacteria

result of natural selection due to the (excessive) use of antibiotics, making treatment and prevention of bacterial infections less effective