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 system do larger organisms have for transport?

  A mass transport system
• 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 do hydrogen bonds between water molecules create?

  Cohesion and adhesion
• 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 diameter through contraction and relaxation
• What do veins carry?

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

  To minimize resistance to flow
• What are the characteristics of capillaries?

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

  1. Four chambers: right atrium, left atrium, right ventricle, left ventricle
  2. Four main blood vessels: pulmonary vein, aorta, vena cava, pulmonary artery
  3. Atrioventricular and semilunar valves
  4. Tendinous chords and septum
  5. Coronary arteries
• 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?

  The hardening of arteries due to plaque

  
• What causes atheroma formation?

  Damage to the endothelium of arteries
• What is the result of plaque build-up 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 triggers the conversion of prothrombin to thrombin?

  Thromboplastin released from platelets
• What does thrombin catalyze?

  The conversion of fibrinogen into fibrin
• What is thrombosis?

  Blood clotting to prevent blood loss
• What forms the framework for a blood clot?

  A network of fibrin fibers
• What is energy balance?

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

  It leads to weight loss
• How is BMI calculated?

  • Divide body mass in kilograms by height in meters squared
  • Compare the value to a chart for classification

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

  1. Monosaccharides: simple sugar monomers
  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