Cardiovascular

• What are the main components of blood?

  Erythrocytes, leucocytes, platelets, and plasma
• Why are erythrocytes red?


  Because they contain haemoglobin
• Where are erythrocytes produced?


  In the bone marrow
• What is the primary function of leucocytes?


  To defend the body against infections
• What are the two types of lymphocytes?

  • B-cells
  • T-cells
• What do B-cells do?


  They produce antibodies to destroy antigens
• What is the role of T-cells?


  To destroy the body's own cells that have been infected or become cancerous
• What are neutrophils known for?


  Being small and fast, and one of the first to respond to infection
• What is the function of monocytes?


  To protect the body against bacterial infection
• What are platelets and their function?


  Fragments of larger cells that help form blood clots
• What is plasma and its role in blood?


  It is the liquid component that carries blood cells and proteins
• What percentage of blood volume does plasma make up?


  About 55 percent
• What is haemoglobin's primary function?


  To transport oxygen in the blood
• What does the immune system do?


  It helps defend against infections
• What does 'cardiovascular' refer to?


  It refers to the heart and blood vessels
• What is the function of the heart?


  To pump blood around the body
• How many chambers does the heart have?


  Four chambers
• What are the names of the upper chambers of the heart?

  The right atrium and left atrium
• What is the thickest muscular wall of the heart?


  The left ventricle
• What is the main artery of the body?

  The aorta
• What does the pulmonary artery do?


  It carries deoxygenated blood from the heart to the lungs
• What is the function of the vena cava?


  To return deoxygenated blood to the heart
• What is the role of the pulmonary vein?


  To carry oxygenated blood from the lungs to the left atrium
• What do the heart valves do?


  They permit blood to flow in one direction only
• What is the first valve blood encounters as it enters the heart?

  The tricuspid valve
• What does the bicuspid valve do?


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


  To stop blood from going back into the heart from the pulmonary artery
• What does the aortic valve do?


  It is found at the exit of the left ventricle where the aorta begins
• What are the two circulatory systems the heart pumps blood through?

  • Pulmonary circulation
  • Systemic circulation
• What happens in pulmonary circulation?


  The right side of the heart pumps deoxygenated blood to the lungs
• What occurs in systemic circulation?


  The left side of the heart pumps oxygenated blood to the rest of the body
• What is the average heart rate of a healthy adult at rest?

  60 to 80 beats per minute
• What are the stages of the cardiac cycle?

  Atrial systole, ventricular systole, and complete cardiac diastole
• What controls the cardiac cycle?


  The electrical activity in the heart
• What is the role of the sinoatrial (SA) node?


  It initiates the heartbeat
• What does the atrioventricular (AV) node do?


  It sends a signal to the ventricles after a short delay
• What are Purkinje fibres responsible for?


  Conducting impulses up the ventricle walls, causing contraction
• What does a normal ECG trace show?


  The electrical activity of the heart
• What does the P wave in an ECG trace represent?


  Atrial contraction
• What does the QRS complex in an ECG trace indicate?


  Ventricular contraction (systole)