B4

Question 1

plasma

Answer 1

•Transports blood cells and other materials

•approximately50%of blood

Question 2

Red blood cells (RBC)

Answer 2

Transport oxygen from lungs to all body cells(Approximately 40-45% blood)

Question 3

White blood cells (WBC)

Answer 3

Defends the body against harmful microorganisms(approximately 1-3% of blood)

Question 4

Platelet

Answer 4

Helps blood to clot to stop bleeding(approximately 4-9% of blood)

Question 5

How does blood clotting work?

Answer 5

A network of proteins traps platelets and RBCs. Dries to form a scab

Question 6

Characteristics of arteries

Answer 6

•carry blood away from your heart and towards organs

•thick walls containing muscle and elastic fibres

•they stretch as blood if forced through a pulse

Question 7

Characteristics of veins

Answer 7

•carry blood from the organs towards your heart

•have thinner walls to prevent backflow

•veins have no pulse

•skeletal muscles help squeeze blood back to the heart

Question 8

Characteristics if capillaries

Answer 8

•form a huge network that links arteries and veins

•are narrow and have very thin walls

•allows fast diffusion of glucose and oxygen

•CO2 and waste products diffuse from cells into the capillaries