circulatory system

• What is haemoglobin's primary function?

  To transport oxygen in red blood cells
• What is the structure of haemoglobin?

  It has a quaternary structure with four polypeptide chains
• What does the term 'affinity' refer to in haemoglobin?

  How 'sticky' haemoglobin is for oxygen
• Where does haemoglobin bind to oxygen with high affinity?

  In the lungs with high partial pressure
• What is the Bohr Effect?

  Lower affinity for oxygen at high carbon dioxide levels
• How do dissociation curves differ among organisms?

  They adapt to different oxygen concentrations
• What do mass transport systems do in multicellular organisms?

  Deliver oxygen and glucose to cells
• Why do mammals need mass transport systems?

  To overcome slow diffusion in large bodies
• What do arteries do?

  Carry blood away from the heart
• Why do arteries have thick muscular walls?

  To cope with high pressure from the heart
• What prevents blood from flowing backwards in veins?

  Valves
• What is the function of capillaries?

  Connect arteries and veins for substance exchange
• What is tissue fluid made of?

  Water, oxygen, glucose, and mineral ions
• How is tissue fluid formed?


  • at areteriole capillary end, hydrostatic pressure excees tissue fluid
  • forcing fluid and dissolved substances out capillary
• What happens at the venule end of the capillary?

  • At venule end, there is less water meaning Ψ lower inside capilarry than tissue fluid
  • Water moves back into the capillary by osmosis down Ψ gradient
• What drains excess tissue fluid?

  The lymphatic system
• How many chambers does the heart have?

  Four chambers
• What divides the heart into two sides?

  The four chambers
• What substances are too big to be forced out of the capillary?

  Red blood cells and large proteins
• What causes the formation of tissue fluid?

  Smaller substances are pushed out of capillaries
• What happens at the arteriole end of the capillary?

  Hydrostatic pressure exceeds tissue fluid pressure
• How does fluid move from the capillary into surrounding spaces?

  It moves down a pressure gradient
• What occurs at the venule end of the capillary?

  Water potential is lower inside the capillary
• How does water return to the capillary?

  By osmosis down a water potential gradient
• Where does excess tissue fluid drain into?

  The lymphatic system
• Why does the left side of the heart have a thicker wall?

  It pumps blood all around the body
• What type of blood does the left side of the heart carry?

  Oxygenated blood
• What type of blood does the right side of the heart carry?

  Deoxygenated blood
• What are the chambers at the top of the heart called?

  Atria- receive blood from veins
• What is the function of the atrioventricular valves?

  Between atria and ventricles - Prevent blood flowing in the opposite direction
• What are the valves between the ventricles and arteries called?

  Semi-lunar valves
• What is the main artery that carries oxygenated blood from the heart?

  Aorta
• What artery delivers deoxygenated blood to the lungs?

  Pulmonary artery
• What is the major vein returning blood from the body to the heart?

  Vena cava
• What vein carries blood from the lungs to the heart?

  Pulmonary vein
• Why do coronary arteries supply blood to the heart muscle?

  To provide oxygen and glucose for respiration
• What leads to a heart attack?

  Blockage in the coronary arteries
• What are the stages of the cardiac cycle?

  1. Atrial systole: Atria contract, ventricles relax
  2. Ventricular systole: Ventricles contract, atria relax
  3. Diastole: Both atria and ventricles relax
• What is systole?

  Muscle contractions of the heart
• What is diastole?

  Relaxation of the heart muscle