cardiovascular system and disease

• Where are the lungs found?

  inside the thorax
• Explain the structure of the thorax?

  1. its the top part of the body
  2. its separated from the bottom half of the body by the diaphragm
  3. the lungs are protected by the rib cages that are surrounded by plural membranes
• Explain the structure of the lungs?

  • air breathed in through the trachea splits into two bronchi
  • the bronchi split into bronchioles
  • the bronchioles split into alveoi (where gas exchange takes place)
• How does the gas exchange work?

  1. oxygen diffuses from the alveoli into the capillaries as there is a higher concentration compared to in the lungs. carbon dioxide diffuses from the capillaries into the lungs (to be breathed out) as there is a higher concentration compared to the lungs
  2. when blood reaches body cells blood is released from rbc to them
  3. at the same time carbon dioxide diffuses out of body cells into blood
• how to calculate the breathing rate?

  breaths per minute= number of breaths/number of minutes
• what is a double circulatory system?

  two circuits joined together
• what does each circuit in the system do?

  the right ventricle pumps deoxygenated blood to lungs which returns to the heart oxygenated

  left ventricle pumps oxygenated blood to body cells where it becomes deoxygenated and returns to heart
• Describe the pathway of blood through the heart?

  1. deoxygenated blood flows into the atria from the vena cava
  2. oxygenated blood flows into the atria from the pulmonary vein
  3. the atria contact pushing blood into the ventricles
  4. when the right ventricle contracts it forces blood out the pulmonary artery to organs
  5. when the left ventricle contracts it forces blood out of the aorta to organs+
  6. the atria fill again and the process starts again
• How is our rating heart rate controlled?

  by pacemaker cells
• How do pacemaker cells work?

  they produce small electrical impulses which spread to surrounding muscles so they contract
• If natural pacemaker cells do not work and the patient has an irregular heart beat we can use .....?


  artificial ones planted under the skin and wire that goes to heart
• what do arteries do and how?

  carry blood away from the heart

  • strong elastic walls to deal with the high pressure
  • thick walls and small lumen
  • thick layers of muscle to make them strong
  • elastic fibres so they can stretch
• What do capillaries do and how?


  involved in exchange materials at the tissue

  • thin wall (one cell thick) increases the rate of diffusion by decreasing distance
  • permeable walls do substances that can diffuse
  • supply food
  • arteries branch into capillaries
• what do veins do and how?

  carry blood back to the heart

  • capillaries branch into veins
  • blood is at lower pressure
  • thin walls (non-elastic) and large lumen+
  • they have valves to prevent back flow
• How do you calculate the rate of blood flow?

  rate of blood flow= volume of blood/number of minutes
• what do red blood cells do?

  carry oxygen from the lungs where it binds to the haemoglobin to the body cells
• Describe the structure of red blood cells?

  • Biconcave disc which gives a large surface area to absorb oxygen
  • no nucleus for more room to carry O2
• what do white blood cells do?


  fight against infection by:

  • engulf and destroying pathogens
  • producing antibodies and antitoxins
  • they have a nucleus
• what do platelets (no nucleus) do?

  help to clot at a wound to stop blood pouring out and microorganisms getting in

  • they are made from cell fragments
• what happened when you don't have many platelets?

  bruising and excessive bleeding
• what does plasma carry?


  everything in blood like:

  • red and white blood cells
  • platelets
  • glucose and amino acids
  • co2
  • hormones
  • proteins
  • urea (from liver to kidneys)
  • antibodies/antitoxins
• Explain coronary heart disease?

  • when the coronary arteries that supply blood to the heart muscle are blocked due to layers of fatty materials
  • this causes them to become narrow which restricts blood flow
  • less oxygen gets to the heart muscle causing a heart attack
• How do stents help lower the risk of a heart attack when having coronary heart disease?


  they open up the arteries so blood can pass through to keep their heart beating
• what are the positives of stents?

  • they are effective for a long time
  • the recovery time from surgery is relatively quick
• what are the negatives of stents?

  • a risk of complications during surgery
  • risk of infection from surgery
  • risk of developing a blood clot (thrombosis)
• what do stations do?

  reduce cholesterol in body
• why is some cholesterol bad?

  LDL causes health problems and cause coronary heart disease

  whereas healthy is an essential lipid needed for our body to function
• how do statins help high cholesterol in the bloodstream?


  they remove the amount of LDL present which slows down the rate of fatty deposits forming
• what are the advantages of stations?

  • reduce the risks of strokes, contrary heart disease and heart attacks
  • they also increase the amount of HDL (good cholesterol)
  • some studies suggest that they may also help other diseases
• what are the disadvantages of statins?

  • they are long-term and have to be taken regularly (easy to forget)
  • can cause side effects like: headaches, kidney failure, liver damage and memory loss
  • the effect of statins is not instant
• ways to treat heart failure?

  1. heart or heart and lungs transplants (these use donor organs)
  2. artificial hearts that are mechanical devices (temporary fix)
• what are the positives of artificial hearts?

  • they are less likely to be rejected by the body as they are made from metals/plastics
• What are the negatives of an artificial heart?

  • the surgery to fit them in can lead to bleeding and infection
  • they don't work as well as healthy natural ones as parts of the heart could wear or the electric motor could fail
  • can cause blood clots that lead to strokes
  • patients have to take drugs to thin their blood (cause issues with bleeding)
• what causes faulty heart valves?

  • old age
  • infection
  • heart attacks
• what can happen to faulty valves?

  • tissue can stiffen so it wont open properly
  • they can become leaky so blood will flow both ways and wont circulate effectively
• mechanical valves and biological

  • its a less drastic procedure than a whole heart transplant
• how and why is artificial blood used?

  its used when a patient has lost lots of blood to keep the volume of blood up +

  • It's a salt (saline solution) which can keep patient alive even if they lose 2/3 of their rbc+
  • can give patients new rbc over time
• Define double circulatory system?

  • blood is pumped to the lungs by the right side of the heart
  • blood is pumped to the body by the left side of the heart
• why is having one ventricle less efficient?


  oxygenated and deoxygenated blood mixes so less oxygen reaches the body