paper 1 unit 2

Question 1

• humans have a ……. circulatory system

Answer 1

double

Question 2

• ………. blood is taken to the lungs and …….. blood returns to the heart

Answer 2

deoxiginated oxyginated

Question 3

• red blood cells transport …….
• they contain ……… and arein the shape of a ……..

Answer 3

oxygen, haemoglobin and biconcave disk

Question 4

• white blood cells defend against pathogens by ………. this procces produces antitoxins
• their flexible shape to allow them to ……. pathogens, this means the enzymes can ……. the pathogens

Answer 4

phagocytosis and antibodies

engulf and digest

Question 5

• platelets help blood ….. at wounds
• small fragments of ….. that clump together.

Answer 5

clot

cells

Question 6

• plasma carries all substances in the blood , have a liquid component that allows small molecules like glucose to ……….

Answer 6

dissolve

Question 7

• arteries carry blood …… from the heart at a ……. pressure
• walls are ….. and the lumen is ……..

Answer 7

away, high

thick, narrow

Question 8

veins carry blood ……… the heart at ……. pressure

walls are ….. and the lumen is ……

veins have …. to prevent the back flow of blood

Answer 8

towards
low

thin
thick

valves