b6.3.8 blood and body defence mechanisms

Question 1

why do scabs form

Answer 1

to prevent micro-organisms entering your blood and stopping you from losing too much blood.

Question 2

how does a scab form

Answer 2

platelets in the blood change the blood protein fibrinogen into fibrin. then, the red blood cells are trapped in the layer of fibrin and this makes the blood clot. That clot hardens, forming a scab

Question 3

what other ways of defence mechanisms are there

Answer 3

skin, acid in stomach, cilia , nasal hairs and tears

Question 4

skin - defence mechanism

Answer 4

physical barrier

Question 5

Acid in stomach- defence mechanism

Answer 5

It kills pathogens in contaminated food

Question 6

Cilia and mucus- defence mechanism

Answer 6

sticky mucus traps pathogens and then the cilia moved it up to the throat, where it is swallowed

Question 7

nasal hairs -defence mechanism

Answer 7

keeps out dust

Question 8

tears-defence mechanism

Answer 8

contains lysozymes that destroy bacteria

Question 9

what are the 2 types of white blood cells

Answer 9

phagocytes and lymphocytes

Question 10

explain phagocytes

Answer 10

they engulf the microorganism

Question 11

explain lymphocytes

Answer 11

they make the antitoxins or antibodies

Question 12

explain antibodies

Answer 12

they bind to the antigens (proteins on the surface), hen it is ingested by the phagocytes.