Immune System

Question 1

Why do we have an immune system

Answer 1

Competition for survival
Protect against assimilation
Protect agains organ damage and air repair
Protect agains parasitism
Regulation of integrity

Question 2

Non specific immunity

Answer 2

Fast acting, same for every infection
Protect against threatening agents and conditions
Immune mechanism acts as a general defence

Question 3

Primary non specific

Answer 3

Protects against entry of pathogen

Question 4

Secondary specific

Answer 4

Protects against reproduction of pathogen

Question 5

Primary defences

Answer 5

1. Skin contains specialised keratinocytes which dry out cytoplasm to form keratin
2. Sebum is oil found on skin
3. Mucus membranes contain ciliated epithelium
4. Body fluids contain lysosomes which break down bacteria
5. Expulsive reflexes to expel pathogens

Question 6

Non specific cellular defences

Answer 6

Once a pathogen enters body past primary defences, non specific mechanisms will try to remove the pathogen
Include
Inflammatory response
Blood clotting cascade
Phagocytosis’

Question 7

Inflammatory response

Answer 7

1. Cells detect damage and release histamines, increase blood flow in that area
2. Histamines cause capillaries to go leaky, releasing phagocytes and blood clotting factors towards to wound
3. Phagocytes engulf bacteria,dead cells and cellular debris
4. Platelets move out of the capillary to seal wounded area

Question 8

Blood clotting

Answer 8

Requires Calcium ions and 12 clotting factors, made from damaged cells and platelets that start an enzyme cascade

Question 9

Phagocytes

Question 10

Phagocytes - neutrophils

Question 11

Phagocytes - macrophages

Question 12

Phagocytosis

Answer 12

1. Phagocytes recognise a forge in maker which is on the outer membrane of the pathogen called antigens
2. Small non specific protein molecules called opsonins attach to the antigens on outer membrane
3. Phagocytes then can bind to the attached opsonins on pathogen antigen,allows (phagocyte) them to get closer to the pathogen - complimentary shapes opsonin on pathogen binds to opsonin receptor on phagocyte
   4.pathogen is engulfed and enclosed in a large vacuole called phagosome
4. Pathogen fuses with lysozymes which are vesicles containing digestive enzyme lysosome
5. Fusion Causes lysosomes to be released and break down pathogen
6. Some special cells and macrophages don’t complete destroy pathogen save the pathogen antigen
7. Cells put pathogen antigen on special protein complex
8. Moves to cell surface membrane so other immune cells can recognise the pathogen antigen
9. Known as antigen presenting cells