Blood and the Heart

• • the heart is made from cardiac tissue/muscle
  • pumps blood around body
  • heart rate (pulse) is measured in bpm- beats per/min
  • We have 2 circulatory systems, heart~lungs and heart~body
• HEART SEQUENCE

  1. deoxygenated blood
  2. vena cava
  3. right atrium
  4. right ventricle
  5. pulmonary artery to lungs
  6. lungs
  7. pulmonary vein back to heart
  8. left atrium
  9. left ventricle
  10. aorta, oxygenated blood to body
• ARTERIES

  • carry oxygenated blood form heart to organs in coronary arteries
  • small lumen in middle, increase pressure, blood flows through
  • thick layer of muscle to squeeze blood through in contraction
  • elastic, stretchy
• VEINS

  • carry blood from organs to heart
  • large lumen in middle, bigger than artery
  • thin layer of muscle, contract but not as effectively as arteries
  • contains valves to stop backflow of blood
• CAPILLARIES

  • very narrow
  • one cell thick, short diffusion pathway
• PACEMAKER CELLS

  • generate electrical impulses across heart
  • causes heart muscle to contract in specific order and pump blood out and away form heart
• COMPONENTS OF BLOOD: PLASMA

  • main component of blood - 55%
  • transports:
  • CO2 from organs to lungs
  • soluble products of digestion (eg, amino acids) from the small intestine to other organs
  • urea from liver to kidneys
• COMPONENTS OF BLOOD: RBCS

  • packed with red pigment called haemoglobin
  • biconcave for maximum SA for oxygen absorption
  • no nucleus - more oxygen can bind to haemoglobin (a protein)
  • OXYGEN + HAEMOGLOBIN ~ OXYHAEMOGLOBIN
  • bind in lungs, reach cells it releases oxygen so that they can respire
• COMPONENTS OF BLOOD: WBCS

  • produce antibodies that attach to pathogens
  • phagocytosis - engulf + digest pathogens
  • antitoxins
• COMPONENTS OF BLOOD: PLATELETS

  • cuts happen, they activate and help form a clot to reduce blood loss
  • have protein to stretch over wound (scab)
• CHOLESTEROL

  • lipid found in cell membrane
  • Too much cholesterol in the blood can cause health conditions like cardiovascular disease
  • increased levels usually because of diet with high fat
• CHOLESTEROL

  • decreased by..
  • A diet low in saturated fats
  • regular physical activity
  • statins