circulatory system 9

• Human blood is red and always red although the shade of red can vary based on how much oxygen is in the blood
• Veins and arteries are often drawn in diagrams as blue or red to show whether they have lower or higher concentrations of oxygen, but that's just how it is used in most diagrams. It doesn't mean the blood, or the veins, or arteries are actually that color
• Human blood


  • Maintains a certain pH, temperature, osmotic pressure
  • Transports hormones, nutrients, gases
• Components of blood

  • Plasma (liquid portion)
  • Red blood cells
  • White blood cells
  • Platelets
• Hemoglobin


  Iron-containing protein in red blood cells that gives blood its red coloring
• Arteries


  Generally carry blood "away" from the heart
• Veins


  Generally carry blood "to" the heart
• Capillaries


  Small blood vessels where oxygen is delivered to organs and tissues and carbon dioxide is picked up
• Blood flow through the heart

  1. Deoxygenated blood enters right atrium

  2. Flows through tricuspid valve to right ventricle

  3. Pumped through pulmonary valve to pulmonary artery

  4. Oxygenated blood returns through pulmonary vein to left atrium

  5. Flows through mitral valve to left ventricle

  6. Pumped through aortic valve to aorta
• The heart needs its own blood supply through coronary arteries to deliver oxygen and glucose
• Atrial septal defect


  Oxygen-rich blood could mix with oxygen-poor blood, causing problems like abnormal heartbeat, stroke, or heart failure
• There continues to be more advancements for treating cardiovascular conditions