T1: 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 their large surface area to volume ratio
• What happens to the surface area to volume ratio as the size of an organism increases?

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

  Because diffusion distance increases and metabolic rate increases
• 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 (e.g., pressure gradient created by the heart)
  4. Maintenance of speed (e.g., contraction of the heart and elastic recoil of arteries)

  
• What type of molecule is water?

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

  Because it can dissolve many biological molecules that are also polar
• What role does hydrogen bonding play in water transport through xylem vessels?

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

  It minimizes temperature fluctuations in living organisms
• What are the main types of blood vessels and their functions?

  • Arteries: Carry oxygenated blood to body tissues
  • Veins: Carry deoxygenated blood to the lungs
  • Capillaries: Facilitate exchange of substances between blood and tissues

  
• What is the function of arteries in the circulatory system?

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

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

  To contract and relax, controlling the diameter of blood vessels
• 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 and a thin endothelium
• What are the components of the heart and their functions?

  1. Four chambers: right and left atria, right and left ventricles
  2. Four main blood vessels: pulmonary vein, aorta, vena cava, pulmonary artery
  3. Atrioventricular valves: separate atria from ventricles
  4. Semilunar valves: separate arteries from ventricles
  5. Tendinous chords: prevent atrioventricular valves from turning inside out
  6. Septum: prevents mixing of oxygenated and deoxygenated blood
  7. Coronary arteries: supply blood to cardiac muscle
  8. Cardiac muscle: thicker on the left side for higher pressure

  
• What are the stages of the cardiac cycle?

  1. Atrial systole: atria contract, forcing blood into ventricles
  2. Ventricular systole: ventricles contract, blood leaves through aorta and pulmonary artery
  3. Cardiac diastole: atria and ventricles relax, preventing backflow of blood

  
• What is atherosclerosis?

  The hardening of arteries caused by the build-up of fibrous plaque called an atheroma
• What causes the formation of an atheroma?

  Damage to the endothelium, leading to an inflammatory response and plaque build-up
• How does the build-up of fibrous plaque affect blood flow?

  It narrows the artery and restricts blood flow, increasing blood pressure
• 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 (CVD) be reduced?

  By stopping smoking, exercising regularly, reducing alcohol consumption, dietary changes, and maintaining a healthy weight
• What is thrombosis?

  Blood clotting that prevents blood loss when a blood vessel is damaged
• What triggers the conversion of prothrombin into thrombin during blood clotting?

  The release of thromboplastin from platelets
• What is the role of thrombin in blood clotting?

  It catalyzes the conversion of fibrinogen into insoluble fibrin
• What is the function of fibrin in blood clotting?

  To form a network of fibers that trap platelets and red blood cells
• What is energy balance?

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

  It leads to weight loss
• How is BMI calculated?

  By dividing body mass in kilograms by height in meters squared

  
• What does a BMI value below 18 indicate?

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

  It suggests a health risk for heart disease
• What are carbohydrates composed of?

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

  Monosaccharides, disaccharides, and 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 when comparing to a chart for body weight?

  The individual is underweight.
• What does a value above 30 indicate when comparing to a chart for body weight?

  The individual is obese.
• How can the waist-to-hip ratio be used in health assessments?

  It determines the likelihood of a person getting heart disease based on fat distribution.
• What waist-to-hip ratio value suggests a health risk?

  A value above 1 suggests a health risk.