the blood ༊*·˚

Question 1

what are the components of the blood?

Answer 1

platelets, red blood cells, white blood cells

Question 2

is the blood a unique tissue?

Answer 2

yes

Question 3

what liquid is the blood based on?

Answer 3

plasma

Question 4

what is the purpose of plasma?

Answer 4

plasma carries platelets, red and white blood cells and many dissolved substances around your body

Question 5

how many litres of blood does the average person have?

Answer 5

4.7-5 litres of blood

Question 6

what colour is plasma?

Answer 6

a yellow liquid

Question 7

what does urea do and where does it originate?

Answer 7

urea is formed in the liver from the breakdown of excess proteins and is carried to your kidneys where it is removed from your blood to form urine

Question 8

what do red blood cells do?

Answer 8

these cells pick up oxygen from the air in your lungs and carry it to where it is needed

Question 9

are there more white or red blood cells in the body?

Answer 9

there are more red blood cells then any other cells in the body- about 5 million in each cubic millimetre of the blood. there is fewer white blood cells in the body in comparison to red blood cells.

Question 10

describe how red blood cells are efficiently adapted and specialised for their role in the body.

Answer 10

• they have a biconcave disc like shape and being concave on both sides gives them an increased surface area to volume ratio for diffusion
• they contain a red pigment called haemoglobin that binds to oxygen
• they have no nucleus, therefore containing more haemoglobin

Question 11

what is the purpose of white blood cells?

Answer 11

they form part of the body’s natural defence system against harmful microorganisms. bonus info: some white blood cells (lymphocytes) form antibodies against microorganisms. some form antitoxins against poisons made by microorganisms. yet others, (phagocytes) engulf and digest invading bacteria and viruses

Question 12

are red or white blood cells bigger in size?

Answer 12

red blood cells are bigger in size

Question 13

what are platelets?

Answer 13

small fragments of cells. they have no nucleus. they are very important in helping blood to clot at the site of a wound. blood clotting is a series of enzyme-controlled reactions that result in converting fibrinogen into fibrin. this produces a network of protein fibres that capture lots of red blood cells and more platelets to form a jelly-like clot that stops you from bleeding to death. the clot dries and hardens to form a scab. this protects the new skin as it grows and stops bacteria from entering through the wound.