Communicable diseases revision

Question 1

Blood clot

Answer 1

1) exposure (of blood / platelets) to
collagen in damaged, blood vessel /
tissue causes clotting response
2) many factors involved in clotting
process
3) soluble fibrinogen converted to
insoluble fibres
4) mesh of fibres traps cells and platelets
5) clot prevents bleeding
6) clot dries out to produce scab
7) scab protects against entry of
pathogens

Question 2

Swelling / redness

Answer 2

1) infection by pathogen
2) detection by mast cells
3) release of, histamine / cell signals,
cause response
4) arterioles dilate allowing more blood to
area causing redness
5) more tissue fluid forms causing
swelling (oedema)
6) phagocytes attracted to area
* phagocytosis of pathogens

Question 3

Discomfort in armpits

Answer 3

1) excess tissue fluid drained to lymph
vessels
2) pathogens in tissue fluid enter lymph
fluidz
3) transported along lymph system to
lymph nodes
4) activity of phagocytes (and
lymphocytes) causes, swelling of
lymph nodes / discomfort in armpit

Question 4

Vaccination

Answer 4

artificial introduction of antigenic material to stimulate an immune response

Question 5

Why is the primary immune response slow

Answer 5

The primary immune response takes time: pathogen must be recognised as foreign; engulfed by macrophages; antigens presented; selection of specific B cell; expansion of B cell clone; differentiation into plasma cells; protein synthesis

Question 6

Why is the variable region different on each antibody

Answer 6

Pathogens have specific antigens; each is a different shape; each immunoglobulin is specific to an antigen; has shape complementary to the specific antigen.