blood vessels

• Arteries:

  • Arteries take blood away from the heart
  • Blood in arteries is high pressure and contains lots of oxygen in the hemoglobin
  • Except for the artery that goes to the lungs
• Veins:

  • Veins take blood to the heart
  • Carry blood from the body to the heart
  • Blood in veins contains less oxygen, so it's not bright red
  • Veins have lower pressure compared to arteries
• Capillaries:

  • Capillaries are tiny blood vessels that take blood to and from cells, like muscles
• Structure of Arteries and Veins:

  • Both have an outer layer of connective and elastic tissue
  • Veins have a thicker outer layer because they are more likely to collapse due to lower blood pressure
  • Both have a layer of smooth muscle tissue
  • Arteries have a thicker layer of muscle tissue to help pump blood
  • Both have an endothelial layer on the inside
• Atherosclerosis:

  • Fatty deposits called atheroma can block an artery
  • A blocked artery can lead to a blood clot (thrombosis)
  • Can cause coronary disease (heart attack) and strokes
• Development of Atherosclerosis:

  • Endothelial tissue on the inside of arteries and veins gets damaged
  • LDL cholesterol accumulates in the wall, causing inflammation
  • White blood cells move in to fix the problem, leading to a build-up of plaque
  • Plaque formation narrows the artery, restricts blood flow, and increases the risk of blood clotting
  • Blood pressure rises, causing more damage to the endothelial tissue
• Major Diseases Caused by Atherosclerosis:

  • Coronary disease (heart attack)
  • Strokes (if the blockage is in the blood going to the brain)
• Smoking and Atherosclerosis:

  • Smoking damages the endothelial tissue
  • Chemicals in cigarette smoke make blood thicker, leading to fatty deposits
  • Smoking raises blood pressure and heart rate, contributing to atherosclerosis