B2 - Organisation

Question 1

Four chambers of the heart

Answer 1

Right atrium, right ventricle, left atrium, left ventricle
• valves to make sure it flows in the right direction

Question 2

What does the right ventricle do?

Answer 2

Pumps deoxygenated blood to the lungs to take in oxygen. Blood then returns to the heart

Question 3

Left ventricle

Answer 3

Pumps oxygenated blood around all other organs of the body. Blood gives up its oxygen at the body cells and the deoxygenated blood returns to the heart to be pumped out to the lungs again

Question 4

Journey of blood in/from the heart

Answer 4

• blood flows into the two atria from the vena cava and the pulmonary vein
• the atria contract, pushing the blood into the ventricles
• ventricles contract, forcing blood into the pulmonary artery and the aorta, and out of the heart.
• the blood then flows to the organs through the arteries, and returns through the veins
• atria fill again and whole cycle starts over

Question 5

What are coronary arteries for?

Answer 5

• branch off aorta
• surround the heart to supply with oxygenated blood

Question 6

Why is the heart described as an organ?

Answer 6

Because it is made up of different tissues performing specific functions

Question 7

Effect of a leak in a valve

Answer 7

• some blood would flow back into the ventricle/heart, so less oxygenated blood pumped to the body
• cells require oxygen for respiration
• less energy transferred
• more tired

Question 8

Describe the advantages/disadvantages of a person having a biological heart valve instead of a mechanical heart valve

Answer 8

Advantages
• reduced risk of blood clots which would cause stroke/heart attack
• reduced risk of blood clot during pregnancy/birth
• reduced risk of serious bleeds if an accident happens
• do not need to carry drugs when travelling, and no risk to foetus from drugs
• lower risk of rejection/immune reaction

Disadvantage
• May be rejected
• may have to go through surgery more than once
• may have to take immunosuppressant drugs
• have to wait for suitable doctor

Question 9

Correct order of blood flowing through the heart

Answer 9

• right atrium
• right ventricle
• pulmonary artery

Question 10

Evaluate use of statins

Answer 10

Advantages :
• easier to take
• no invasive procedure
• decrease blood cholesterol
• slow down build up of fatty materials in the arteries
• maintain blood flow to heart muscle cells
• low cost compared to a stent operation

Disadvantages:
• might be side effects of drug, e.g. muscle pain
• effect will take time to happen
• drug will need to be taken long term
• might forget to take drug

Question 11

Evaluate use of stents

Answer 11

Advantages:
• blocked artery is held open
• blood flow to heart muscle cells increases
• stent will remain in place for a long time
• effect of stent is immediate
• rapid recovery from the operation

Disadvantage:
• risk of infection from operation
• risk of surgery, e.g. heart attack or bleeding
• risk of thrombosis or blood clot

Question 12

Explain why heart attack survivors get out of breath so easily

Answer 12

• heart cannot contract as powerfully
• less blood is pumped out of heart to body on each contraction
• less oxygen reaches cells for aerobic respiration
• breathing rate increases to supply more oxygen, or -
• breathing rate increases to repay oxygen debt

Question 13

What are valves for?

Answer 13

Make sure blood flows in the right direction

Question 14

What side is the vena cava on?

Answer 14

Right

Question 15

What side is the pulmonary artery on?

Answer 15

Left

Question 16

What side is the aorta on?

Answer 16

Left

Question 17

What side is the pulmonary vein on?

Answer 17

Left

Question 18

What is a pacemaker?

Answer 18

• resting heart rate is controlled by a group of cells in the right atrium wall that act as a pacemaker
• cells produce a small electric impulse - spreads to surrounding muscle cells - causes them to contract

Question 19

What is an artificial pacemaker?

Answer 19

• used to control heartbeat if natural pacemaker cells don’t work properly
• (if patient has an irregular heartbeat)
• device implanted under the skin and has a wire going to the heart
• produces electric current to jeep heart beating regularly

Question 20

Three different types of blood vessel

Answer 20

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

Question 21

Arteries

Answer 21

• pumps blood out at high pressure so artery walls are strong and elastic
• walls are thick compared to the size of the linen (hole down the middle)
• contain thick layers of muscle to make them strong, and elastic fibres to allow them to stretch and spring back

Question 22

Capillaries

Answer 22

• arteries branch into capillaries
• really tiny
• carry the blood close to every cell in the body to exchange substances with them
• permeable walls - substances can diffuse in and out
• supply food and oxygen - take away waste like CO2
• walls are usually only one cell thick
• increases rate of diffusion by decreasing the distance over which it occurs

Question 23

Veins

Answer 23

• capillaries join up and form veins
• blood is at a lower pressure in veins so walls don’t need to be as think as in arteries
• bigger lumen than arteries to help the blood flow despite the lower pressure
• valves to help keep blood flowing in the right direction

Question 24

Calculating the rate of blood flow

Answer 24

Rate of blood flow = volume of blood / number of minutes

Question 25

What is the blood?

Answer 25

• a tissue
• acts as a huge transport system

Question 26

Four main things in the blood

Answer 26

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

Question 27

Job of red blood cells

Answer 27

• carry oxygen from lungs to all cells in the body
• shape is a biconcave disc - give large surface area for absorbing oxygen
• no nucleus - more room for oxygen
• contain red pigment - haemoglobin
• in lungs - haemoglobin binds to oxygen to become oxyhaemoglobin
• body tissue - reverse happens oxyhemoglobin splits up into haemoglobin and oxygen, to release oxygen to the cells

Question 28

White blood cells

Answer 28

• defend against infection
• some can change shape for phagocytosis
• others produce antibodies and antitoxins to fight microorganisms
• have a nucleus

Question 29

Platelets

Answer 29

• help blood clot at a wound to stop blood pouring out/ microorganisms coming in
• small fragments of cells
• no nucleus
• lack can cause excessive bleeding and bruising

Question 30

Plasma

Answer 30

• liquid which carries everything
• red and white blood cells and platelets
• nutrients like glucose and amino acids
• carbon dioxide from organs to the lungs
• urea from liver to kidneys
• hormones
• proteins
• antibodies and antitoxins

Question 31

What is an artificial heart?

Answer 31

• mechanical devices that pump blood for a person whose heart has failed (and can’t find a donor for transplant)
• temporary fix until a donor heart can be found/help a person recover by allowing heart to rest and heal
• some cases used as a permenant fix

Question 32

Main advantage of artificial hearts

Answer 32

• less likely to be rejected by immune system than a donor heart
• because made of plastic so not recognised as foreign (not attacked like living tissue)

Question 33

Disadvantages of artificial hearts

Answer 33

• surgery to fit can lead to bleeding/infection
• don’t work as well as healthy/natural ones
• parts of heart could wear out
• electrical motor could fail
• blood doesn’t flow smoothly - can cause blood clots and lead to strokes
• have to take drugs to thin their blood and make sure this doesn’t happen
• this can cause problems with bleeding if hurt in an accident

Question 34

Biological/mechanical valves

Answer 34

• can be taken from humans or other mammals (biological)
• or can be man-made (mechanical)
• less drastic procedure than whole heart transplants but still major surgery
• can still be problems with blood clots

Question 35

Fault heart valves

Answer 35

• valves can be damaged or weakened by heart attacks/infection/old age
• cause valve tissue to stiffen so it won’t open properly
• valve may become leaky - blood doesn’t circulate correctly