blood

Question 1

what is blood?

Answer 1

a complex tissue consisting of plasma, platelets & 2 types of cells

Question 2

what is the liquid component called?

Answer 2

plasma

Question 3

what are the cell fragments called?

Answer 3

platelets

Question 4

what are the 2 types of blood cells found in the blood?

Answer 4

red blood cells & white blood cells

Question 5

what is plasma?

Answer 5

• straw coloured liquid
• transports blood cells & other substances: glucose & amino acids, urea & CO2, proteins & heat energy

Question 6

what are red blood cells?

Answer 6

• biconcave discs
• no nucleus but lots of haemoglobin
• transport oxygen

Question 7

what are phagocytes (white blood cells)?

Answer 7

• larger cells with a multi-lobed nucleus
• engulf and digest pathogens

Question 7

what are platelets?

Answer 7

• cell fragments
• release chemicals when the blood is exposed to air- causes soluble fibrinogen to be converted to insoluble fibrinogen
• fibrin forms a mesh which traps platelets & red blood cells- this is a clot (scab)

Question 8

what are lymphocytes? (white blood cells)

Answer 8

• cells with a very large nucleus
• make & release antibodies which bind to & destroy pathogens

Question 9

how are red blood cells specialised for their jobs? (oxygen)

Answer 9

• contain haemoglobin- protein that combines with oxygen to form oxyhaemoglobin- transports oxygen to respiring cells

Question 10

how are red blood cells specialised for their job (nucleus)?

Answer 10

• no nucleus- more haemoglobin can be packed into each cell and more oxygen can be transported

Question 11

how are red blood cells specialised for their job? (shape)

Answer 11

• biconcave (discs with a dip in the middle)
• increases their SA:V ratio & decreases the distance to the centre of the cell- increases rate of diffusion

Question 12

what is it called when phagocytes engulf & digest pathogens?

Answer 12

phagocytosis

Question 13

how do phagocytes engulf & digest pathogens?

Answer 13

• they have a sensitive cell surface membrane that can detect chemicals made by pathogenic cells
• once they enter the pathogenic cell, they will engulf it & release digestive enzymes to digest it
• its a non-specific immune response

Question 14

how can phagocytes be easily recognised?

Answer 14

by their multi-lobed nucleus & their granular cytoplasm

Question 15

how can lymphocytes be easily recognised?

Answer 15

• large, round nucleus which takes up most of the cell
• clear, non-granular cytoplasm

Question 16

what are antibodies?

Answer 16

Y- shaped proteins with a shape that is complementary to the antigens on the surface of the pathogen

Question 17

what do lymphocytes produce?

Answer 17

antitoxins to neutralise toxins released by pathogens

Question 18

how are antibodies destroyed?

Answer 18

• antibodies attach to the antigens and cause agglutination (clumping together)
• the pathogenic cells cannot move easily
• chemicals are released to signal to phagocytes that there are cells present that need to be destroyed

Question 19

what is the immune systems main component?

Answer 19

white blood cells

Question 20

what are platelets involved in?

Answer 20

blood clotting and forming scabs where the skin has been cut or punctured

Question 21

what happens when you have a wound?

Answer 21

platelets arrive to stop the bleeding

Question 22

the chemicals that platelets release do what?

Answer 22

• cause soluble plasma protein fibrinogen to be
  changed into the insoluble fibrous protein fibrin
• the fibrin forms a network of fibres across the cut which trap platelets and red blood cells
• this forms a clot or scab which prevents further blood loss
• also acts as a barrier to prevent the entry of pathogens

Question 23

the importance of blood clotting?

Answer 23

• prevents significant blood loss from wounds
• scab formation seals the wound with an insoluble patch that prevents entry of microorganisms that could cause infection
• it remains in place again, until new skin has grown underneath it, sealing the skin again