CB8

• Exchange surfaces


  -Thinner walls- quicker diffusion

  -Large surface area- more space for diffusion

  -Good blood supply- maintain steep concentration gradient
• Blood made up of- Plasma


  A transport medium

  -Transports dissolved substances e.g. waste carbon dioxide produced by cells
• Blood made up of- Erythrocytes


  Red blood cells

  -Collect oxygen within the lungs and transport it to cells that need it

  -Bio-concave disk structure for bigger surface area for diffusion

  Lots of haemoglobin which binds oxygen plus no nucleus for more space
• Blood made up of- Platelets


  Small fragments of cells

  -Clots blood at site of wound
• Blood made up of- Lymphocytes


  White blood cells

  -Part of bodies defence system

  -produce anti-bodies
• Phagocytes


  Engulf and digest invaders

  -Neutralise toxins and produce anti-bodies
• Arteries


  Carry blood away from your heart towards the organs

  -Thick walls containing muscle fibres, so they stretch as blood is forced through them.

  ~No valves
• Capillaries


  Form a huge network that link arteries and veins

  -Narrow, thin walls for faster diffusion of glucose and oxygen

  ~No valves
• Veins


  Carry blood away from organs to the heart

  -Thinner walls

  -Valves to prevent backflow

  -No pulse but skeletal muscles to help squeeze blood back to the heart
• Heart has four chambers


  Right atrium, left atrium

  Right ventricle, left ventricle
• Why is the muscle on the left side of the heart thicker?


  It has to push blood around the whole body
• Why coronary heart disease can cause other issues with organs?


  -Not enough glucose/oxygen so no respiration

  -Heart would contract less so less blood to organs
• Heart-rate


  Number of times the heart beats in a min
• Cycle of blood around the heart

  1. Vena cava
  2. Right atrium
  3. Right ventricle
  4. Pulmonary artery
  5. Lungs
  6. Pulmonary vein
  7. Left atrium
  8. Left ventricle
  9. Aorta
  10. Body

  
• Circulatory system


  Made up of the heart and blood vessels.

  Transports substances around the body in the blood
• Cardiac output


  Stroke volume x heart rate = cardiac output

  (litres/min) (litres/beats)
• Osmosis- hypertonic


  The solution is concentrated
• Osmosis- hypotonic


  Solution is dilute
• Osmosis- isotonic


  No difference in concentration and the movement of water remains constant
• Aerobic respiration


  Glucose + oxygen ---> carbon dioxide + water

  ~exothermic reaction
• Anaerobic respiration


  'Without oxygen'

  -Realises less energy than aerobic

  Glucose ----> Lactic acid
• Why don't we use anaerobic respiration more often?


  -Produces less energy

  -Produces lactic acid- when built in muscle tissues can cramp

  -Leaves oxygen debt
• Controlled variable


  You do not change
• Independent variable


  They change
• Dependent variable


  Changes itself
• Control variable


  Keep the same during the experiment
• How is oxygen and carbon dioxide exchanged in the alveoli?


  -Carbon dioxide diffuses from the blood into the alveoli