Section 5 - Blood and Organs

Question 1

blood’s four main components

Answer 1

plasma
placelets
red blood cells
white blood cells

Question 2

what is plasma

Answer 2

plasma is a pale yellow liquid that carries just about everything that needs transporting around the body

Question 3

what does plasma transport

Answer 3

1) red and white blood cells and platelets
2) digested food products (like glucose and amino acids) from gut to all body cells
3) carbon dioxide from body cells to lugs
4) urea from liver to kidneys (where its removed as urine)
5) hormones which act as chemical messegers
6) heat energy

Question 4

what do red blood cells do

Answer 4

transport oxygen from lungs to all body cells

Question 5

how is red blood cell adapted

Answer 5

1) small and biconcave shape to give a large surface area for absorbing and releasing oxygen
2) they contain haemoglobin (gives blood its colour) containing lots of iron. i the lugs it reacts with oxygen to become oxyhaemogloin. in body tissues the reverse reaction occurs to release oxygen in the cells
3) red blood cells dont have a nucleous - leaving space for more haemoglobin to carry more oxygen

Question 6

what are pathogens

Answer 6

organisms that cause disease

Question 7

two types of pathogens

Answer 7

phagocytes and lymphocytes

Question 8

inmune system job

Answer 8

destroy pathogens that have entered body and prevent them from reproducing rapidly

Question 9

phagocytes

Answer 9

INGEST pathogens

1) detect things foreign to body and engulf and digest them
2) they are non-specific so they attack anything that is not meant to be there

Question 10

lymphocytes

Answer 10

produce antibodies

1) every pathogen has unique molecules (antigens) on its surface
2) when certain white blood cells (lymphocytes) come across a foreign antigen they start producing proteins called antibodies.
- these lock on the pathogens and mark them out for destruction by other white blood cells.
- these antibodies are specfic to that type of antigen and wont lock on any others
3) antibodies are produced rapidly and flow around body to mark all similar pathogens
4) memory cells are also produced

Question 11

what are memory cells

Answer 11

• they are produced as a response to a foreign antigen
• and remain in the body remembering the specific antigen
• they can reproduce fast if the same antigen enters body again

Question 12

three types of blood vessel and their function

Answer 12

arteries - carry blood away from heart
capillaries - involved in exchange of materials at tissues
vein - carry blood to heart

Question 13

arteries

Answer 13

1) heart pumps blood at high pressure so the walls are strong and elastic
2) the elastic fibres allow arteries to expand
3) the walls are thick compared to the lumen (hole in middle). thy contain thick muscle layers to make them strong
4) largest artery in body is the aorta

Question 14

capillaries

Answer 14

1) arteries branch into capillaries
2) capillaries are really tiny
3) carry blood really close to every cell in body to exchange substances with them
4) they have permeable walls so substances can diffuse in and out
5) supply food and oxygen and take away waste such as CO2
6) the walls are usually one cell thick (increased rate of diffusion by decreasing the distance over which it happens)

Question 15

veins

Answer 15

1) capillaries eventually join up to form veins
2) the blood is at a lower pressure so the walls don’t have to be as thick as artery walls
3) they have a bigger lumen to help blood flow despite lower pressure
4) they have valves to keep blood flow in right direction
5) largest vein in body is the vena cava

Question 16

kidney roles

Answer 16

excretion organ part of urinary system

1) removal of urea from blood (urea is produced in liver from excess amino acids)
2) adjustment of (ion) salt levels in blood
3) adjustment of water content in blood

They do this by filtering stuff out of blood in high blood pressure and reabsorbing the useful things - the end product being urine

Question 17

blood around heart journey

Answer 17

1) right atrium of heart receives deoxygenated blood from body through vena cava
2) The deoxygenated blood moves through to the right ventricle which pumps it to the lungs via the pulmonary artery
3) left atrium received oxygenated blood from the lungs through pulmonary vein
4) the oxygenated blood then moves through to the left ventricle which pumps it around the whole body via the aorta

Question 18

heart adaptations

Answer 18

• The left ventricle has a much thicker wall than the right ventricle. it needs more muscle because it has to pump blood around the whole body
• whereas the right ventricle only has to pump it to the lungs
• this also means the blood left in the left ventricle is under higher pressure than the blood on the right
• valves prevent the back-flow of blood

Question 19

how does heart rate increase with exercise

Answer 19

1) exercise increases amound of co2 in blood
2) high levels of blood co2 are detected by receptors in aorta and carotid artery (an artery i neck)
3) these receptors send signals to brain
4) brain sends signals to heart causing it to contract more often and with more force

Question 20

why does heart rate increase with exercise

Answer 20

when you exercise your muscles need more energy so you respire more because you need more oxygen into cells and remove CO2 quicker so your heart rate increases

Question 21

hormonal system and heart rate

Answer 21

1) when an organism is threatened the adrenal glands release adrenaline
2) adrenaline binds to specific receptors in heart causing the cardiac muscle to contract more frequently and with more force, so heart rate increases and heart pumps more blood
3) this increases oxygen supply in tissues getting body ready for action

Question 22

what is coronary heart disease

Answer 22

• it is when the coronary arteries that supply blood to muscle of heart get blocked by layers of fatty material building up
• this causes arteries to become narrow so blood flow is restricted and there is a lack of oxygen to the heart muscle - which can lead to a heart attack

Question 23

risk factors of coronary heart disease

Answer 23

1) diet high in saturated fats which can lead to fatty deposits forming inside arteries which can lead to coronary heart disease
2) smoking. it increases blood pressure which can cause damage to the inside of coronary arteries. chemicals in cigarette smoke can also cause damage. this damage makes it more likely that fatty deposits will form, narrowing the coronary arteries
3) being inactive. it can lead to high blood pressure which ca damage the lining of the arteries making the formation of fatty deposits more likely.

Question 24

oxygenated and deoxygenated and arteries and veins

Answer 24

normally arteries carry oxygenated blood and veins carry deoxygenated blood however the pulmonary artery and pulmonary vein are exceptions

Question 25

pulmonary meaning

Answer 25

to do with the lungs

Question 26

hepatic meaning

Answer 26

to do with the liver

Question 27

renal meaning

Answer 27

to do with the kidneys