further reading heart

• What is the cardiac cycle?

  One complete cycle of heart events
• What does the sinoatrial node do?

  Generates electrical impulses for heart contraction
• What type of muscle is cardiac muscle?

  Myogenic
• What is the function of the atrioventricular node?

  Relays electrical impulses to the ventricles
• What does ECG stand for?

  Electrocardiogram
• What is the role of Purkyne tissue?

  Transmits impulses across the ventricles
• What is cardiac output?

  Volume of blood pumped per minute
• How is cardiac output calculated?

  Cardiac output = stroke volume × heart rate
• What happens to cardiac output during strenuous exercise?

  It increases due to higher oxygen demand
• What is pulse rate?

  Expansion and recoil of artery walls
• Why is the heart described as a double pump?

  It pumps blood to both lungs and body
• Describe the flow of blood through the heart.

  Right atrium → right ventricle → lungs → left atrium → left ventricle → body
• What prevents backflow of blood in the heart?

  Closure of the heart valves
• What sound does the closure of AV valves produce?

  First heart sound (lub)
• What sound does the closure of semilunar valves produce?

  Second heart sound (dub)
• What is diastole?

  Period when the heart muscle relaxes
• What is systole?

  Period when the heart muscle contracts
• How many times does the cardiac cycle repeat per minute?

  About 72 times
• What does an ECG monitor?

  The electrical impulses of the heart
• What can differences in an ECG trace indicate?

  Possible heart problems
• What is blood pressure?

  Pressure exerted by circulating blood
• How is blood pressure measured?

  Using a sphygmomanometer
• What units are used for blood pressure?

  Millimetres of mercury (mmHg)
• What does a sphygmomanometer measure?

  Blood pressure in arteries
• What is hypertension?

  High blood pressure
• What blood pressure values indicate hypertension?

  More than 140/90 mmHg
• What are the main components of the circulatory system?

  • Heart
  • Blood vessels (arteries, veins, capillaries)
  • Blood
• What are the differences between arteries, veins, and capillaries?

  Arteries:

  • Thick walls
  • High pressure
  • No valves

  
  

  Veins:

  • Thin walls
  • Low pressure
  • Valves present

  
  

  Capillaries:

  • One cell thick walls
  • Site of exchange
  • Connect arterioles and venules
• What is the function of arterioles and venules?

  Arterioles:

  • Regulate blood flow to tissues
  • Connect arteries to capillaries

  
  

  Venules:

  • Carry blood from capillaries to veins
• What is the significance of elastic recoil in arteries?

  • Maintains blood pressure
  • Smooths out blood flow
• What are the advantages of a double circulatory system?

  • Increases efficiency of oxygen delivery
  • Maintains higher systemic blood pressure
• How does the structure of capillaries facilitate gas exchange?

  • One cell thick walls
  • Large surface area
  • Short diffusion distance
• What is the role of a defibrillator in cardiac emergencies?

  • Sends voltage to restore heart rhythm
  • Stops uncoordinated heart contractions
• What lifestyle changes can help prevent coronary heart disease?

  • Regular blood pressure checks
  • Avoid smoking
  • Limit alcohol and salt intake
  • Eat a balanced diet
• What is the role of aspirin in treating heart conditions?

  • Anti-inflammatory
  • Inhibits blood clot formation
• What is the function of the lungs in the circulatory system?

  • Oxygenate blood
  • Remove carbon dioxide
• What is the significance of the alveoli in the lungs?

  • Increase surface area for gas exchange
  • Maintain steep concentration gradient
• What is the purpose of a peak flow meter?

  • Measures rate of air breathed out
  • Assesses lung function during asthma attacks
• What is the relationship between surface area and volume in larger organisms?

  • Larger organisms have a smaller surface area to volume ratio
  • Diffusion alone is insufficient for gas exchange
• What is the role of squamous cells in the lungs?

  • Form a thin layer for efficient diffusion
  • Reduce diffusion distance for gases