The heart structure

• Vena cava


  Large vein that returns deoxygenated blood to the heart
• Cardiac output


  The volume of blood pumped through each ventricle per minute
• Calculation of cardiac output

  Cardiac output = Heart rate x Stroke volume
• Pathway of blood flow

  • Deoxygenated blood to pulmonary artery
  • Oxygenated blood from pulmonary vein to left atrium
  • Deoxygenated blood from right atrium
  • Oxygenated blood from left atrium to left ventricle
• The left and right ventricles pump the same volume of blood through the aorta and pulmonary artery
• Electrocardiogram


  Detects the heart's electrical activity
• Heart sounds


  • First heart sound created by closure of AV valves
  • Second heart sound created by closure of semilunar valves
• Blood pressure


  • Increases during ventricular systole
  • Decreases during diastole
  • Typical reading for young adult is 120/80 mmHg
• Measuring blood pressure


  1. Inflatable cuff stops blood flow

  2. Deflates gradually

  3. Systolic pressure when blood starts flowing

  4. Diastolic pressure when blood flows freely
• Hypertension is a major risk factor for many heart diseases
• Sino-atrial node (SAN)


  The pacemaker that sets the rate of heart contractions
• Atrioventricular node (AVN)


  Impulses from SAN travel here and then down to ventricles
• Autonomic nervous system


  • Sympathetic: releases noradrenaline, increases heart rate
  • Parasympathetic: releases acetylcholine, decreases heart rate
• The medulla regulates the rate of the SAN through the antagonistic action of the autonomic nervous system
• Vena cava


  Large vein that returns deoxygenated blood to the heart
• Cardiac output


  The volume of blood pumped through each ventricle per minute
• Calculation of cardiac output

  Cardiac output = Heart rate x Stroke volume
• Pathway of blood flow

  • Deoxygenated blood to pulmonary artery
  • Oxygenated blood from pulmonary vein to left atrium
  • Deoxygenated blood from right atrium to right ventricle
  • Oxygenated blood from left ventricle to aorta
• The left and right ventricles pump the same volume of blood
• Electrocardiogram


  Detects the heart's electrical activity
• Heart sounds


  • First heart sound created by closure of AV valves
  • Second heart sound created by closure of semilunar valves
• Blood pressure


  • Increases during ventricular systole
  • Decreases during diastole
  • Typical reading for young adult is 120/80 mmHg
• Measuring blood pressure


  1. Inflatable cuff stops blood flow

  2. Deflates gradually

  3. Systolic pressure when blood starts flowing

  4. Diastolic pressure when blood flows freely
• Hypertension is a major risk factor for many heart diseases
• Sino-atrial node (SAN)


  The pacemaker that sets the rate of heart contraction
• Atrioventricular node (AVN)


  Impulses from SAN travel here and then down to ventricles
• Sympathetic nervous system


  Releases noradrenaline, increases heart rate
• Parasympathetic nervous system


  Releases acetylcholine, decreases heart rate
• Vena cava


  A large vein that returns deoxygenated blood to the heart
• Large vein


  Refers to the size of the vena cava, making it one of the largest veins in the body