Lifestyle & Risk

• What essential substances do animals require to survive?

  Oxygen and carbon dioxide
• How do small organisms meet their transport needs?

  Through diffusion due to large surface area
• What happens to the surface area to volume ratio as organism size increases?

  It decreases
• Why does diffusion become insufficient in larger organisms?

  Because diffusion distance increases
• What is a mass transport system in larger organisms composed of?

  A heart and circulation
• What are the features of a mass transport system?

  1. A network to move through (e.g., vessels)
  2. A medium for movement (e.g., blood)
  3. Controlled direction for substance movement
  4. Maintenance of speed through heart contraction
• What type of molecule is water?

  A polar molecule
• Why is water considered a polar solvent?

  It can dissolve many biological molecules
• What role does hydrogen bonding play in water transport?

  It creates cohesion and adhesion
• What is the significance of water's high heat specific capacity?

  It minimizes temperature fluctuations
• What are the main characteristics of arteries?

  • Carry oxygenated blood (except pulmonary artery)
  • Small lumen for high blood pressure
  • Thick smooth muscle layer
  • Elastic fibers for stretch and recoil
• What are the main characteristics of veins?

  • Carry deoxygenated blood (except pulmonary vein)
  • Large lumen to minimize resistance
  • Thinner muscle and elastic fiber layer
  • Valves to prevent backflow
• What are the main characteristics of capillaries?

  • Very small to fit between cells
  • Narrow lumen
  • Thin endothelium (one cell thick)
• What are the four chambers of the heart?

  1. Right atrium
  2. Left atrium
  3. Right ventricle
  4. Left ventricle
• What are the four main blood vessels associated with the heart?

  1. Pulmonary vein
  2. Aorta
  3. Vena cava
  4. Pulmonary artery
• What is the function of atrioventricular valves?

  They separate atria from ventricles
• What is the role of semilunar valves?

  They separate arteries from ventricles
• What do tendinous chords do in the heart?

  Prevent atrioventricular valves turning inside out
• What is the function of the septum in the heart?

  Prevents oxygenated and deoxygenated blood mixing
• What is the purpose of coronary arteries?

  Supply blood to cardiac muscle
• Why is cardiac muscle thicker on the left side of the heart?

  Higher pressure is needed to pump blood
• What are the three stages of the cardiac cycle?

  1. Atrial systole
  2. Ventricular systole
  3. Cardiac diastole
• What occurs during atrial systole?

  Atria contract, forcing blood into ventricles
• What happens during ventricular systole?

  Ventricles contract, blood leaves heart
• What occurs during cardiac diastole?

  Atria and ventricles relax, pressure decreases
• What is atherosclerosis?

  Hardening of arteries due to plaque buildup

  
• What causes atheroma formation?

  Damage to the endothelium lining arteries
• What is the role of white blood cells in atherosclerosis?

  They move into the artery during inflammation
• What is the consequence of plaque buildup in arteries?

  Narrowing of the artery and restricted blood flow

  
• What are the risk factors for atherosclerosis?

  • Genetics
  • Age
  • Diet
  • Gender
  • High blood pressure
  • High cholesterol levels
  • Smoking
  • Physical inactivity
  • Obesity
• How can the risk of cardiovascular disease be reduced?

  By stopping smoking and exercising regularly
• What diseases can atherosclerosis lead to?

  Angina, stroke, myocardial infarction, aneurisms
• What is thrombosis?

  Blood clotting to prevent blood loss
• What triggers the conversion of prothrombin to thrombin?

  Thromboplastin released from platelets
• What does thrombin do in the clotting process?

  Converts fibrinogen into insoluble fibrin
• What forms the framework of a blood clot?

  A network of fibrin trapping platelets
• What is energy balance?

  Balance of calories consumed and burned
• What happens if more calories are burned than consumed?

  It leads to weight loss
• How is BMI calculated?

  Body mass in kg divided by height in m²
• What does a BMI value below 18 indicate?

  The individual is underweight