Content

• What are the primary functions of erythrocytes?


  To transport oxygen from the lungs to tissues and carbon dioxide from tissues to lungs
• What percentage of carbon dioxide waste do erythrocytes transport back to the lungs?


  About 24 percent
• What is the common name for an erythrocyte?


  Red blood cell (RBC)
• What are the primary functions of erythrocytes?


  To pick up oxygen from the lungs and transport it to the body's tissues, and to pick up carbon dioxide waste at the tissues and transport it to the lungs for exhalation
• Where do erythrocytes typically remain?


  Within the vascular network
• How does the shape of erythrocytes optimize gas exchange?


  The biconcave shape provides a greater surface area across which gas exchange can occur, relative to its volume
• What structural proteins do erythrocytes contain that help maintain their shape and enable them to change shape?


  Spectrin, a cytoskeletal protein element
• Why do erythrocytes lack mitochondria?


  Because they rely on anaerobic respiration and do not utilize the oxygen they are transporting
• What other organelles do erythrocytes lack as they mature?


  Nucleus and most other organelles
• How does the biconcave shape of erythrocytes enable them to move through narrow blood vessels?


  The biconcave shape enables erythrocytes to change their shape to squeeze through capillaries
• How does the oxygen carried by erythrocytes reach the cells in the capillaries?


  The oxygen can diffuse from the erythrocytes into the plasma and then through the capillary walls to reach the cells
• How does the carbon dioxide produced by cells get picked up by erythrocytes?


  Some of the carbon dioxide produced by the cells diffuses into the capillaries to be picked up by the erythrocytes
• What are the key structural features of erythrocytes and how do they relate to their functions?


  • Biconcave disc shape: Provides greater surface area for gas exchange relative to volume
  • Lack of nucleus and organelles: Allows more space for hemoglobin, enabling efficient oxygen/CO2 transport
  • Cytoskeletal proteins (e.g. spectrin): Maintain shape and enable deformation to squeeze through capillaries
  • Lack of mitochondria: Rely on anaerobic respiration, conserving oxygen for delivery to tissues
• What is the normal heart rate for a healthy adult?

  60 to 100 beats per minute
• What occurs during the cardiac cycle?


  The heart contracts (systole) and then relaxes (diastole)
• How many times is the cardiac cycle repeated on average per minute?


  70 times a minute
• What are the stages of the cardiac cycle?

  • Atrial systole: contraction of the right and left atria
  • Ventricular systole: contraction of ventricles
  • Complete cardiac diastole: relaxation of the atria and ventricles
• Where is the SA node located?


  In the right atrium of the heart
• What is the function of the SA node?


  It acts as the pacemaker for setting the rhythm of the heart
• What is the role of the AV node?


  It receives impulses from the SA node and passes them on to the ventricles
• What are Purkinje fibres?


  Specialised fibres that rapidly transmit impulses from the atrioventricular node
• What does the ECG represent?


  • The waves represent the electrical activity of the heart
  • Different sections represent different activities within the heart
• What does the P wave indicate on an ECG?


  The atrial contraction
• What does the QRS complex show on an ECG?


  The ventricular contraction (systole)
• What does the T wave indicate on an ECG?


  The ventricles relaxing (diastole)
• What does a disordered ECG indicate?


  Which part of the heartbeat is problematic
• What is the scale for the ECG trace?


  10 mm = 1 mV
• What is the duration of the PR interval on an ECG?


  0.20 sec
• What are the functions of the main parts of the heart?

  • Aorta: Main artery, carries oxygenated blood from the left ventricle to body cells
  • Pulmonary artery: Carries deoxygenated blood from heart to lungs
  • Pulmonary vein: Collects oxygen-rich blood from lungs to heart
  • Left atrium: Receives blood full of oxygen from lungs
  • Mitral valve: Regulates blood flow from left atrium to left ventricle
  • Left ventricle: Pumps oxygenated blood to the body
  • Right ventricle: Pumps deoxygenated blood to the lungs
  • Tricuspid valve: Controls blood flow from right atrium to right ventricle
  • Pulmonary valve: Prevents backflow of blood from pulmonary artery
  • Right atrium: Receives deoxygenated blood from the body
  • Superior vena cava: Returns blood from the body to the right atrium
• What is the function of the aorta?


  It carries oxygenated blood from the left ventricle to body cells
• What does the pulmonary artery do?


  It carries deoxygenated blood from the heart to the lungs
• What is the role of the pulmonary vein?


  It collects oxygen-rich blood from the lungs to the heart
• What does the left atrium do?


  It receives blood full of oxygen from the lungs
• What is the role of the right ventricle?


  It pumps deoxygenated blood to the lungs
• What does the tricuspid valve do?


  It controls blood flow from the right atrium to the right ventricle
• What is the function of the pulmonary valve?


  It prevents backflow of blood from the pulmonary artery
• What does the right atrium do?


  It receives deoxygenated blood from the body
• What is the role of the superior vena cava?


  It returns blood from the body to the right atrium
• What does the right atrium do?


  Receives deoxygenated blood
• What is the function of the pulmonary artery?


  It takes deoxygenated blood to the lungs