Chp4

• Red blood cells


  • Carries oxygen around the body
  • 45% of blood
• White blood cells


  • Fights diseases such as bacteria and virus
  • 1% of blood
• Platelets


  • Helps blood clot when we cut ourselves
  • 4% of blood
• Plasma


  • Carries dissolved nutrients around the body for cells to use
  • Carries dissolved waste around the body so we can get rid of them
  • 50% of blood
• Adaption of red blood cells


  • No nucleus - can contain more haemoglobin
  • Large surface area
  • Contain haemoglobin - binds to oxygen
  • Biconcave disk shape
  • Thin cell membrane - flexible
• White blood cells can change shape so they can squeeze out blood vessels to get to the infection
• Platelets are able to change shape
• Plasma is watery which means things can dissolve in it easier
• Blood Vessels


  • Arteries
  • Veins
  • Capillaries
• Arteries


  • Thick muscular walls
  • Lots of elastic tissue in the walls
  • Relatively small lumen
  • Carry blood under high pressure
  • No valves
• When the heart pumps


  The blood flows in pulses through the arteries which widens the lumen. This is your pulse.
• Blood Circulation System


  1. Pulmonary artery

  2. Lungs

  3. Pulmonary vein

  4. Heart

  5. Aorta

  6. Rest of body
• Blood Circulation System


  • Contains a pump to sustain high pressure
  • Contains valves to control the flow
  • Contains vessels to distribute blood
• Arteries 


  Carries blood AWAY from heart
• Veins


  Carry blood TOWARDS the heart
• Veins


  • Thin muscular walls
  • Little of elastic tissue in the walls
  • Relatively large lumen
  • Valves to prevent backflow
• Tunica Adventitia

  The outermost layer of a blood vessel
• Veins:

  Blood flow under low pressure.

  Blood flows slowly.

  No pulses
• Tunica intima


  • Innermost layer of a blood vessel
• Capillaries


  • Single layer of endothelial cells
  • No muscle
  • No elastic tissue in walls
  • No valves
  • Thin, permeable walls 1 cell thick
• Capillaries


  • Allow rapid diffusion of materials through a tissue
  • Link up arteries and veins
• Capillaries form a branching network
• Body cells are never far away from a capillary
• Blood flow is slowing down as it passes along the capillaries
• Blood pressure falls as it passes along the capillaries
• Capillaries have a large surface area because there are so many of them
• Atrioventricular valve


  Found both sides of the heart between atria and ventricles. Right side called the tricuspid valve. Left side called the bicuspid valve. Prevent backflow into ventricles.
• Semilunar valve


  Found at the base of the pulmonary artery and the aorta. Prevent backflow into the ventricles.
• Heart parts


  • Superior vena cava
  • Pulmonary artery
  • Right atrium
  • Right ventricle
  • Aorta
  • Pulmonary vein
  • Semilunar valve
  • Left atrium
  • Atrioventricular valve
  • Left ventricle
  • Inferior vena cava
  • Septum
• The left side of the heart is thicker than the right because when it contracts, the left has to get blood to the brain and further away than the right (has to go to lungs).
• Stent insertion


  1. Artery is getting blocked, person in pain or has heart attack

  2. Stent inserted in place

  3. Balloon carrying stent in the damaged artery inflated so stent expands

  4. Balloon is then removed to leave stent in place

  5. Stent becomes part of the artery wall
• Statins


  Medicines that can help lower the level of low density lipoprotein (LDL) cholesterol in the blood. Taken as tablets once a day for life. Can interact with other medicines. Many people experience no/few side effects, but rarely kidney failure or other potentially dangerous side effects. The risks balance the beneficial side effects - 1/50 people who take statins for 5 years will avoid a serious event (heart attack/stroke).
• Arrhythmia


  An abnormal heart rhythm (heart beating too fast/slow or with an abnormal rhythm). Caused by a problem with the heart's electrical system.
• Heart's electrical system


  1. The heart's natural pacemaker in the right atrium generates an electrical current that causes the atrium to contract

  2. The electric current goes down to the bottom of the ventricles, which then contract from the bottom up
• Artificial pacemaker


  A small box that lies just below the collarbone, which detects changes in the electrical activity of the heart and sends electric impulses to cause the heart to beat when it is not functioning properly. Can be recharged by computer.
• Heart transplant


  Required in cases of heart failure. Advantages are that artificial hearts aren't rejected by the body and can keep the patient alive while waiting. Disadvantages are the risks of surgery like bleeding and infection, and the need to take immunosuppressant drugs and blood thinners after the transplant. Parts of the transplanted heart can also wear out over time.
• Nose


  Mucus/hour which catches bacteria/dirt
• Epiglottis


  Controls if food or air goes down
• Trachea


  • Relatively flexible and is kept open by rings of cartilage
• Bronchi


  • Connect trachea to lungs - splits air 2 ways (contains cartings)