12.5 Non-specific Animal Defences Against Pathogens

Question 1

Mucous membrane

Answer 1

Membrane lining many body tracts eg. airways of the gas exchange system that secretes sticky mucus

Question 2

Thromboplastin

Answer 2

Enzyme triggering a cascade of reactions resulting in blood clotting

Question 3

Serotonin

Answer 3

Makes smooth muscle in blood vessel walls contract, so they narrow and reduce supply of blood to the area

Question 4

Mast cell

Answer 4

Type of white blood cell that is found in connective tissue around the body. Involved in the first stages of interaction with a pathogen

Question 5

Histamine

Answer 5

Causes blood vessels to dilate, raised temperatures prevent pathogens reproducing

Question 6

Cytokines

Answer 6

Attract phagocytes to the site, dispose of pathogens by phagocytosis

Question 7

Phagosome

Answer 7

A vacuole that is created when a phagocyte engulfs the pathogen.

Question 8

Phagolysosome

Answer 8

Occurs when a phagosome combines with a lysosome

Question 9

Lysosome

Answer 9

Sac-like compartment in a cell that produces enzymes in order to break down pathogens

Question 10

Major histocompatibility complex (MHC)

Answer 10

Binds peptide fragments derived from pathogens and displays on a the cell surface for recognition by appropriate T cells

Question 11

Antigen-presenting cell

Answer 11

Occurs when the MHC moves antigens onto the macrophage’s surface membrane

Question 12

Macrophage

Answer 12

Specialised cells that are able to present antigens to T cells and initiate inflammation by releasing cytokines

Question 13

Cytokine

Answer 13

Cell-signalling molecule, informing other phagocytosis of the pathogen presence. Produced whrn phagocytes engulf a pathogen

Question 14

Opsonins

Answer 14

Chemicals that bind to pathogens to ‘tag’ them in order for them to be recognised as non-self by phagocytes