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• Cardiovascular system is made up of the heart, blood vessels, and blood

  
• Heart

  • Muscular organ w/ 4 chambers and 2 connecting pumps
• Blood flow through cardiovascular system

  1. Left atrium

  2. Left ventricle

  3. Aorta

  4. Arteries

  5. Arterioles

  6. Capillaries

  7. Venules

  8. Veins

  9. IVC and SVC

  10. Right atrium

  11. Right ventricle

  12. Pulmonary arteries

  13. Lungs

  14. Pulmonary veins

  15. Left atrium

  
• Right side of heart

  Pumps deoxygenated blood from body to lungs for oxygenation

  
• Left side of heart

  Pumps oxygenated blood from lungs to body
• Atria

  • Receive blood
• Ventricles

  • Pump blood out
• Blood flows through the cardiovascular system in a continuous loop
• The heart is a muscular organ weighing 7-15 oz
• Heart walls

  • Made of cardiac muscle
  • Left side more muscular than right
  • Left ventricle has thickest wall (about 12 in. thick)
• Heart valves

  • Atrioventricular valves

  1. Tricuspid valve (right)
  2. Bicuspid valve (left)

  • Semilunar valves

  1. Pulmonary
  2. Aortic
• Heart valves

  Ensure one-way blood flow and prevent backflow
• Heartbeat phases

  1. Systole

  2. Diastole
• Systole

  Ventricles contract, AV valves close, blood pumped out of ventricles
• Diastole

  Heart relaxes, semilunar valves close, atria fill the ventricles with blood
• Cardiac output

  Total blood volume pumped by the ventricle in a minute (ml/min)
• Cardiac output is influenced by size, age, cardiovascular, and systemic health
• Electrical conduction system

  Heart has myogenic activity, meaning it can beat without nervous system input
• Electrical impulse pathway

  1. Sinoatrial node

  2. Atrioventricular node

  3. Bundle of His

  4. Purkinje fibers
• Blood vessels

  • 3 main types: arteries, veins, and capillaries

  
• Arteries

  • Thick, strong vessels that carry blood away from heart
  • Most carry oxygenated blood (except pulmonary and umbilical)
  • Thick walls with lots of smooth muscle
• Veins

  • Thinner and less elastic
  • Carry blood back to heart
  • Can stretch to hold large volumes of blood
• Capillaries

  • Smallest blood vessels
  • Single layer of cells
  • Thin walls for easy exchange of nutrients, gases, and waste products

  
• Red blood cells pass through capillaries all the time
• Damage to capillaries can cause blood to leak into surrounding area
• Blood composition

  • Plasma (55%)
  • Cells (45%)

  
• Plasma


  • Liquid containing nutrients, salts, gases, hormones, proteins
• Blood cells

  • Red blood cells
  • White blood cells
  • Platelets

  
• Red blood cells (erythrocytes)

  Transport oxygen throughout body
• Each red blood cell contains 250 million hemoglobin molecules, each capable of binding 4 oxygen molecules
• Red blood cells lack nuclei and mitochondria, allowing them to carry more hemoglobin and avoid using oxygen they carry
• Red blood cells live about 120 days before being broken down in the spleen and liver
• White blood cells (leukocytes)

  Smaller portion of blood, but play a crucial role in the immune system
• Types of white blood cells

  • Granulocytes
  • Agranulocytes
• Granulocytes

  • Visible granules
  • Involved in fighting infections and inflammation
• Agranulocytes

  • Lymphocytes
  • Monocytes
• Lymphocytes

  Essential for immune response, B cells produce antibodies, T cells attack infected cells
• Monocytes

  Become macrophages when they enter tissues, helping digest foreign substances
• Platelets

  Tiny fragments from large cells in marrow called megakaryocytes, crucial for blood clotting
• Nutrients are absorbed in the small intestine to enter the bloodstream through capillaries