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 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 organisms
• What are the main types of blood vessels and their functions?

  • Arteries: Carry oxygenated blood to tissues
  • Veins: Carry deoxygenated blood to lungs
  • Capillaries: Facilitate exchange between blood and cells
• What is the function of arteries in the circulatory system?

  To carry oxygenated blood to body tissues
• Why do arteries have a small lumen?

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

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

  Deoxygenated blood
• What is the purpose of valves in veins?

  To prevent backflow of blood
• What is the structure of capillaries?

  Very small with a narrow lumen
• Why is the endothelium of capillaries one cell thick?

  To maintain a short diffusion distance
• What are the components of the heart and their functions?

  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 valves
  4. Septum: prevents mixing of blood types
• What is the function of the coronary arteries?

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

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

  1. Atrial systole: atria contract, valves open
  2. Ventricular systole: ventricles contract, valves close
  3. Cardiac diastole: heart relaxes, pressure decreases
• What is atherosclerosis?

  Hardening of arteries due to plaque buildup

  
• What causes the formation of an atheroma?

  Damage to the endothelium and plaque buildup
• What are the risk factors for atherosclerosis?

  Genetics, age, diet, gender, blood pressure
• How can the risk of cardiovascular disease be reduced?

  • Stop smoking
  • Regular exercise
  • Reduce alcohol consumption
  • Dietary changes
  • Maintain healthy body weight
• What is thrombosis?

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

  Thromboplastin released from platelets
• What is the role of fibrin in blood clotting?

  Forms a network to trap blood cells
• 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?

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

  A health risk for heart disease
• What are carbohydrates made of?

  • Carbon
  • Hydrogen
  • Oxygen
• What are the three types of saccharides?

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

  A simple sugar monomer
• What is a disaccharide?

  Two monosaccharides
• What is a polysaccharide?

  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 is waist-to-hip ratio used in health assessment?

  Determines risk of heart disease