Human Circulatory System

• Red blood cells carry oxygen around the body. Contain haemoglobin rich in iron when turns to oxyhaemoglobin when combined with oxygen
• Red bloods cells adapted by:

  1. biconcave shape for max diffusion of oxygen and larger surface area
  2. No nucleus so more space for haemoglobin
• White blood cells prevent disease by destroying microorganisms
• two types of white blood cell

  1. lymphocytes
  2. phagocytes
• Platelets are involved in the blood clotting process
• Blood clotting process

  1. cell fragments trigger conservation of fibrinogen to fibrin
  2. forms a meshwork snd red blood cells get caught causing the blood to clot
  3. clotting reduces blood loss and prevents entry of micro organisms
• Plasma is a transport medium
• Plasma transports

  1. food molecules
  2. CO2
  3. Hormones
  4. Urea
• Artery

  1. Thick walls with present muscle and elastic fibres
  2. High blood pressure
  3. no valves
  4. transports blood away from heart
  5. High 02 level Low CO2 level
• Vein

  1. Thin walls with present muscle and elastic fibres
  2. Low blood pressure
  3. Present valves
  4. transports blood back to heart
  5. Low O2 level High CO2 level
• Capillary

  1. Walls one cell thick with absent muscle and elastic fibres
  2. Low blood pressure
  3. no valves
  4. Links arteries and veins
  5. mixed 02 levels and mixed CO2 levels
• Arteries

  Oxygenated blood to body organs

  EXCEPT

  pulmonary artery: deoxygenated blood to lungs
• Veins

  Deoxygenated blood to heart

  EXCEPT

  Pulmonary vein: oxygenated blood to heart
• Aorta

  oxygenated blood from heart to body
• Vena cava

  deoxygenates blood from body to heart
• Hepatic artery

  carries blood containing oxygen and glucose to liver
• Hepatic portal vein

  carries blood containing digested food from small intestine to liver
• Hepatic vein

  carries blood containing glucose and amino acids from liver around body

  and C02 back to lungs
• Renal artery

  Carries blood rich in urea to kidneys for excretion
• renal vein

  carries purified blood from kidney to vena cava

  also co2 back to heart and lungs
• right atrium

  recieves blood from body
• left atrium

  recieves blood from lungs
• valves

  prevent back flow
• right ventricle

  pumps blood to lungs
• left ventricle

  pumps blood around body
• Heart contracts 70 times per minute which is made possible by the special cardiac muscle in its walls that never get tired
• Humans have a double circulatory system which means blood travels through the heart twice on one circulation of the body
• Exercise strengthens the heart

  stronger heart=increased cardiac output
• recovery rate

  time it takes for the pulse to return to normal after excercise
• Effect exercise has on the heart

  • causes heart rate to rise
  • heart pumps more blood to muscles
  • muscles get more oxygen and glucose for respiration
  • extra glucose and oxygen supplied through increased cardiac output