circulatory

• What do different organisms have regarding haemoglobin?

  Different types of haemoglobin
• How does haemoglobin with low affinity for oxygen behave?

  It binds less easily but releases easily
• What is the behavior of haemoglobin with high affinity for oxygen?

  It binds easily but releases less easily
• What happens to oxygen affinity during a shift to the right?

  Decreased affinity for oxygen
• Why do organisms with high metabolic rates need to release oxygen easily?

  To supply oxygen to respiring tissues
• What occurs during a shift to the left regarding oxygen affinity?

  Increased affinity for oxygen
• Why do organisms in low oxygen environments need increased affinity for oxygen?

  To pick up available oxygen efficiently
• What is the structure of the circulatory system described?

  • Closed double system
  • Blood travels through the heart twice per circuit
  • Blood contained within vessels
  • Blood serves as a transport medium
• What is the advantage of lower blood pressure in pulmonary circulation?

  It avoids damaging alveoli in lungs
• How does the heart affect blood pressure in systemic circulation?

  It increases blood pressure for faster flow
• What do atrioventricular valves prevent?

  Backflow of blood into the atria
• What do semilunar valves prevent?

  Backflow from arteries into ventricles
• What is the structure of haemoglobin?

  • Group of proteins with quaternary structure
  • Consists of 4 polypeptide chains (2 alpha, 2 beta)
  • Each chain associated with a haem group
  • Haem group contains iron (Fe)
• How many oxygen molecules can each haemoglobin associate with?

  Four oxygen molecules
• What is the definition of affinity for oxygen?

  Tendency of a molecule to bind with oxygen
• How does partial pressure of oxygen (PO2) affect haemoglobin affinity?

  Higher PO2 increases haemoglobin affinity
• What happens to oxygen at high PO2?

  Oxygen loads onto haemoglobin
• What occurs at lower PO2 regarding oxygen?

  Oxyhaemoglobin unloads its oxygen
• What is the cooperative binding of oxygen in haemoglobin?

  • Binding of one oxygen molecule changes structure
  • Exposes other binding sites
  • This phenomenon is called positive cooperativity
• How does carbon dioxide affect haemoglobin's affinity for oxygen?

  It reduces haemoglobin's affinity for oxygen
• What is the Bohr effect?

  Increased CO2 raises oxygen unloading rate
• What happens to blood pressure during systole?

  Blood pressure increases
• What happens to blood pressure during diastole?

  Blood pressure decreases
• What is the process of blood circulation through the heart?

  1. Blood enters left and right atria
  2. Atria contract, pushing blood into ventricles
  3. Ventricles contract, circulating blood to the body
  4. Heart relaxes to fill with blood again
• What is the role of the muscle layer in arteries compared to veins?

  Thinner in arteries than in veins
• What is tissue fluid?

  Fluid that surrounds cells in tissues
• How does hydrostatic pressure affect tissue fluid formation?

  It drives water out of blood vessels
• What happens to fluid as it returns to the blood via osmosis?

  Fluid returns due to lower hydrostatic pressure
• What is the composition of plasma?

  • Water
  • Nutrients (glucose, amino acids)
  • Waste products (urea, carbon dioxide)
  • Proteins (albumin, globulins)
• What is lymph?

  Fluid that drains into lymphatic vessels
• How does lymph differ from blood plasma?

  Less oxygen and more fats
• What are the risk factors for coronary heart disease?

  Atherosclerosis, smoking, high cholesterol
• What symptoms are associated with coronary heart disease?

  Chest pain, shortness of breath
• What causes blockage in coronary heart disease?

  Build-up of fatty substances in vessels
• What are the effects of lifestyle on coronary heart disease?

  • Smoking increases risk
  • High cholesterol contributes to blockage
  • Regular exercise can reduce risk