12.5 Non-specific Animal Defences

Question 1

are non specific or specific responses quicker

Answer 1

non specific; they’re always present and respond rapidly to pathogens or injuries

Question 2

What are examples of how our body generically protects us from pathogens

Answer 2

1. skin is a barrier to outside world
2. many body tracts are lined with mucous membranes to trap bacteria and pathogens
3. lysozymes in tears and urine

Question 3

What are expulsive mechanisms

Answer 3

when our body tries to force a pathogen out by coughing, sneezing, vomiting etc.

Question 4

What happens when we cut ourselves

Answer 4

Our blood works to seal the wound before pathogens can enter the body through the blood clotting cascade

Question 5

What’s the process of the blood clotting cascade

Answer 5

1. platelets in the blood surround the site and stick to the wound because of the reaction to the oxygen in the air
2. platelets begin secreting and EMZYME, called THROMBOPLASTIN; which triggers serotonin to release (neurotransmitter)
3. serotonin makes muscles around the wound contract to reduce blood supply
4. THROMBOPLASTIN converts a protein in the blood called PROTHROMBIN into THROMBIN (an enzyme)
5. CALCIUM IS NEEDED FOR THIS TO WORK - makes platelets stickier to start closing up wound
6. THROMBIN transforms FIBRINOGEN (protein in plasms) into FIBRIN (with platelets, forms the clot)

Question 6

What’s the inflammatory response

Answer 6

inflammation is a mix of heat, redness and swelling; MAST CELLS are activated in damaged tissues and release HISTAMINES & CYTOKINES.

Question 7

what’s a mast cell

Answer 7

a migrant cell of connective tissue that contain many granules of histamine and heparin

Question 8

What do histamines do

Answer 8

make blood vessels dilate,
cause heat and redness,
heat causes temperatures to increase degrees above 37 degrees reducing pathogen reproduction,
make blood vessels ‘more leaky’ to force plasma out into tissue fluid causing swelling,

Question 9

what do opsonins do

Answer 9

bind to pathogens to make them more recognisable to WBCs

Question 10

what do cytokines do

Answer 10

attract WBCs to the site,
they’re for phagocytosis,
increase body temperature

Question 11

What’s the second line of defence in animals

Answer 11

neutrophils and macrophages

Question 12

What are neutrophils and macrophages

Answer 12

neutrophils take 10 minutes to engulf and destroy a pathogen
macrophages take longer but the macrophage combines antigens from the pathogen with glycoproteins called MHC (major histocompatibility complex) becoming an APC (antigen presenting cell)

Question 13

What’s the process of phagocytosis using neutrophils and macrophages

Answer 13

1. pathogen in the body releases toxins that attracts a phagocyte
2. the phagocyte recognises it as non-self and binds to it
3. phagocyte engulfs pathogen to from phagosome; lysosomes move towards the phagosome and combines with it to form phagolysosome.
4. in phagolysosomes, enzymes break down pathogens
5. digested pathogen absorbed by phagocyte - antigens combine with MHC in the cytoplasm
6. MHC/antigen complex is displayed on phagocyte membrane, making an antigen presenting cell.