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 and metabolic rate rises
• What is a mass transport system in larger organisms composed of?

  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 for transport
• What is the significance of water's high heat specific capacity?

  It minimizes temperature fluctuations in living things
• What do arteries carry?

  Oxygenated blood to body tissues
• Why do arteries have a small lumen?

  To maintain high blood pressure
• What is the function of smooth muscle in arteries?

  To control the diameter of blood vessels
• What do veins carry?

  Deoxygenated blood to the lungs
• Why do veins have a large lumen?

  To minimize resistance to flow
• What is the structure of capillaries?

  Very small with a narrow lumen
• What is the purpose of the atrioventricular valves?

  To separate atria from ventricles
• What are the main components of the heart?

  1. Four chambers: right/left atria, right/left ventricles
  2. Four main blood vessels: pulmonary vein, aorta, vena cava, pulmonary artery
  3. Valves: atrioventricular and semilunar
  4. Septum: prevents blood mixing
• What occurs during atrial systole?

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

  Ventricles contract, blood leaves the 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 endothelium from various factors
• What is the result of plaque buildup in arteries?

  Narrowing of arteries 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 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 is energy balance?

  • Balance of calories consumed vs. burned
  • Greater calories burned leads to weight loss
  • Fewer calories burned leads to weight gain
• How is BMI calculated?

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

  Individual is underweight
• What does a waist-to-hip ratio above 1 suggest?

  Increased risk of heart disease
• What are carbohydrates made of?

  Carbon, hydrogen, and oxygen
• What are the types of saccharides?

  1. Monosaccharides: simple sugar monomer
  2. Disaccharides: two monosaccharides
  3. Polysaccharides: many monosaccharides
• What does a value below 18 indicate in BMI?

  Individual is underweight
• What does a value above 30 indicate in BMI?

  Individual is obese
• How does waist-to-hip ratio relate to heart disease risk?

  A value above 1 suggests a health risk
• What are the three types of saccharides?

  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• What is a monosaccharide?

  Simple sugar monomer