4.2.2.3 Blood

Question 1

What is blood?

Answer 1

blood is a tissue consisting of plasma, in which the red blood cells, white blood cells and platelets are suspended

Question 2

What are the functions of blood?

Answer 2

• transports O2 to the rest of the body so cells can do aerobic respiration and release energy
• transports CO2 from all cells back to the lungs
• transports nutrients from digestive system to all cells
• transports waste products from cells to the liver and kidney for treatment and disposal
• transports heat around the body
• transports water around the body
• transports salts around the body
• transports white blood cells to fight infections
• transports hormones around the body

Question 3

What 4 main components is blood made up of?

Answer 3

• red blood cells
• white blood cells
• platelets
• plasma

Question 4

Diagram of red blood cells:

Answer 4

Question 5

Function of red blood cells:

Answer 5

to carry oxygen in the blood from the lungs to the cells in the body’s tissues so that they can do aerobic respiration and release energy to be able to do their processes

Question 6

Adaptations of red blood cells:

Answer 6

• biconcave disk shape means that the cell has a large SA:V which helps it to absorb oxygen as it increases the efficiency of diffusion of oxygen into and out of the cell and reduces the diffusion distance to the centre of the cell
• doesn’t contain a nucleus - increases space for haemoglobin and creates room inside the cells allowing them to carry more oxygen
• red blood cells contain a substance called haemoglobin (a red chemical which contains iron) - helps red blood cells to absorb oxygen as it binds to oxygen which means it can transport it from the lungs to the body’s tissues
• in the lungs haemoglobin combines with oxygen to form oxyhemoglobin
  
  • in the body’s tissues, oxyhemoglobin breaks down to haemoglobin, releasing oxygen from the red blood cell - the released oxygen can be taken up by cells
• they are tiny and flexible so that they can fit through narrow capillaries

Question 7

How do red blood cells travel?

Answer 7

red blood cells travel suspended in the plasma

Question 8

What is the most common blood cell?

Answer 8

red blood cells

Question 9

Diagram of white blood cells:

Answer 9

Question 10

Function of white blood cells:

Answer 10

Are part of the immune system so their function is to defend the body against infections from microorganisms (pathogens) e.g. bacteria

Question 11

What are the two type of white blood cells?

Answer 11

• Phagocytes
• Lymphocytes

Question 12

How do white blood cells travel?

Answer 12

white blood cells travels suspended in plasma

Question 13

Function of phagocytes:

Answer 13

kill microorganisms like bacteria if they get into the blood

Question 14

Adaptations of phagocytes:

Answer 14

• are very flexible so they can kill microorganisms by surrounding and engulfing them
• once the microorganism is inside the phagocyte it is digested by powerful enzymes and killed
• phagocytes are attracted to bacteria because bacteria produce waste products (chemicals) called toxins (these are the chemicals that make us feel ill) - when a phagocyte moves towards a bacterium it surrounds it and engulfs it this is called phagocytosis

Question 15

Function of lymphocytes:

Answer 15

• to produce chemicals called antibodies
• antibodies stick onto foreign micro-organisms in the blood, this either kills the microorganisms or causes them to clump together making it easier for phagocytes to engulf and destroy them
• protect the body as they are able to neutralise the harmful poisons or ‘toxins’ produced by microorganisms

Question 16

Adaptations of lymphocytes:

Answer 16

protect the body as they are able to neutralise the harmful poisons or ‘toxins’ produced by microorganisms by producing antibodies

Question 17

Diagram of platelets:

Answer 17

Question 18

Function of platelets:

Answer 18

• a series of small fragments of cells that help blood to clot blood (at a wound)
• when a blood vessel is damaged platelets seal and clot the wound
• this prevents blood cells from being lost from the blood and also stops microorganisms entering the blood through the wound

Question 19

Adaptations of platelets:

Answer 19

• no nucleus
• fragments of cells
• able to change shape - often form astar shape with tentacles which help to plug any broken bloodvessels
• without them, cuts would result in excessive bleeding and bruising

Question 20

How do platelets travel?

Answer 20

platelets are suspended in plasma

Question 21

What is blood clotting and how does it work?

Answer 21

• blood clotting is a series of reactions resulting in the change of fibrinogen (a soluble blood protein) to fibrin (an insoluble blood protein), which forms network of fibres trapping blood cells and forming a clot
• the clot then hardens to form a scab which allows new skin to grown underneath while preventing any microorganisms from entering

Question 22

Diagram showing how platelets are involved in blood clotting:

Answer 22

Question 23

Diagram of plasma:

Answer 23

Question 24

What is plasma?

Answer 24

a straw coloured liquid that carries the components in blood: red blood cells, white blood cells, platelets, glucose, glycerol, amino acids, carbon dioxide, urea, lactic acids, hormones, proteins, antibodies, and antitoxins

Question 25

Function of plasma:

Answer 25

• to carry all of the different types of cells contained in the blood (e.g. red blood cells, white blood cells, platelets etc.)
• carbon dioxide is produced as a waste product by cells in the body tissues, this carbon dioxide is dissolved in the blood plasma so that it can be transported to the lungs and removed from the body
• the sugar glucose is also carried to the body tissues by being dissolved in the blood plasma

Question 26

Adaptations of plasma:

Answer 26

since blood plasma is a liquid it is able to carry some substances by them being dissolved directly into the blood plasma

Question 27

What is the composition of blood?

Answer 27

Question 28

Haemoglobin:

Answer 28

a red iron-containing protein that combines with oxygen found in red blood cells

Question 29

Oxyhaemoglobin:

Answer 29

oxygen combines with haemoglobin to form oxyhaemoglobin (oxygen binds reversibly to haemoglobin)

Question 30

Where is oxyhemoglobin most likely to be found?

Answer 30

oxyhaemoglobin is most likely to be found in red blood cells in the lungs

Question 31

What mineral is needed to make haemoglobin?

Answer 31

iron is the mineral needed to make haemoglobin

Question 32

Why are people who are deficient in iron anaemic?

Answer 32

people who are deficient in iron are anaemic as iron is the mineral needed to make haemoglobin so they can’t make as much haemoglobin so red blood cells can’t carries much oxygen to cells around the body meaning they can’t do as much aerobic respirations so can’t release as much energy so feel more tired especially when doing more exercise

Question 33

What are good dietary sources of iron?

Answer 33

red meats, liver, lentils, chickpeas are good sources of iron

Question 34

What is the function of haemoglobin?

Answer 34

• in the lungs, haemoglobin binds with oxygen
• it is now called oxyhemoglobin and is bright red
• oxygenated blood arrives at the heart
• the heart pumps oxygenated blood around the body
• reaches the tissues in the capillaries
• oxyhemoglobin releases oxygen into the tissues becoming deoxyhaemoglobin and dark red
• it then returns to the heart via the lungs

Question 35

Do white blood cells have a nucleus?

Answer 35

Yes