1
Q
What is plasma?
A
- a pale yellow liquid
- the liquid part of blood
- carries almost everything that needs transporting around your body
2
Q
What does plasma carry?
A
- red blood cells, white blood cells and platelets (used in blood clotting)
- water
- digested food products like glucose and amino acids from the gut to body cells
- carbon dioxide from body cells to lungs
- urea from the liver to the kidneys (where it’s removed in the urine)
- hormones:chemical messengers
- antibodies:proteins in a immune response
3
Q
How are red blood cells adapted to their function?
A
- small and bioconcave shape to give large surface are to volume ration for absorbing and releasing oxygen
- contains haemoglobin, which gives blood its colour–it contains iron
- no nucleus to have more space for haemoglobin, so they can carry more oxygen
- very flexible to pass easily through the tiny capillaries
4
Q
What are the three blood vessels?
A
- arteries to carry blood away from the heart
- capillaries are involved in the exchange of materials at the tissues
- veins carry blood to the heart
5
Q
What is the structure of arteries?
A
- carry blood under high pressure so the walls are strong and elastic
- walls are thick compared to the size of the lumen
- the walls contain thick layers of muscle to make them strong
6
Q
What is the structure of veins?
A
- capillaries eventually join up to form veins
- the blood pressure is lower in the veins so the walls are not as thick as artery walls
- bigger lumen than arteries to help blood flow despite the low pressure
- valves to keep blood flowing in the right direction
7
Q
What is the structure of capillaries?
A
- arteries branch into capillaries
- too small to see
- carry blood really close to every cell in the body to exchange substances with them
- permeable walls, so substances diffuse in and out
- supply food and oxygen, take away wastes like CO2
- walls usually one cell thick, this increases the rate of diffusion by decreasing the distance over which it occurs
8
Q
What is a double circulatory system?
A
- mammals have this
- the first system, heart pumps deoxygenated blood to the lungs to take in oxygen
- the blood returns to the heart
- the second system, heart pumps oxygenated blood to the rest of the body
9
Q
What are the advantages of a double circulatory system?
A
- blood returning to the heart after picking up oxygen means it can be pumped around the body at much higher pressure
- this increases rate of blood flow to the tissues (blood can be pumped around the body much faster), so more oxygen can be delivered to cells
- this is important because mammals use up a lot of oxygen maintaining their body temperature
10
Q
How does blood travel through the heart?
A
- vena cava
- right atrium
- right ventricle
- plumonary artery
- lungs
- pulomonary vein
- left atrium
- left ventricle
- aorta
- whole body
11
Q
What does haemoglobin do?
A
- combine with oxygen in the lungs to become oxyhaemoglobin
- in body tissues they do the reverse to release oxygen into the cells
12
Q
Why does the left ventricle have a thicker wall than the right ventricle?
A
-because it has to pump blood to the whole body, whereas the right ventricle only has to pump blood to the lungs
13
Q
What are the valves in the heart and what do they do?
A
- semilunar, tricuspid, bicuspid
- prevent backflow of blood
