Heart

Understanding the Heart

  • The heart is a muscular organ that pumps blood through the blood vessels of the circulatory system.
  • It is located in the chest, slightly left of centre.
  • The average human heart beats about 70 times per minute, circulating the blood through the body to supply oxygen and nutrients and remove waste products.

Structure of the Heart

  • The human heart has four chambers: the right atrium, right ventricle, left atrium, and left ventricle.
  • Blood returns to the heart through two large veins, the Superior vena cava (returns blood from the body regions above the diaphragm) and the Inferior vena cava (returns blood from the body regions below the diaphragm), into the right atrium.
  • Blood flows from the right atrium into the right ventricle, and then it is pumped to the lungs through the pulmonary artery.
  • Oxygenated blood returns to the heart from the lungs via the pulmonary veins into the left atrium.
  • From the left atrium, the blood flows into the left ventricle, and it is then pumped to all other parts of the body through the aorta.

Blood Flow through the Heart

  • Deoxygenated blood enters the right atrium from the superior and inferior vena cava.
  • From the right atrium, blood moves into the right ventricle which pumps the blood to the lungs through the pulmonary artery.
  • In the lungs, the blood picks up oxygen (oxygenated blood) and flows back to the heart through the pulmonary veins into the left atrium.
  • The left atrium contracts and pushes the blood into the left ventricle.
  • The left ventricle contracts and pumps the oxygenated blood out through the aorta to all parts of the body.

Heartbeat and Pulse

  • The heartbeat is the rhythmic contraction and relaxation of the heart muscles.
  • The rate and rhythm of the heartbeat are controlled by a group of cells in the right atrium known as the sinoatrial node or pacemaker.
  • The pulse is the rhythmic expansion and recoiling of the artery wall with each beat of the heart, and it can be felt in any place that allows an artery to be compressed against a bone.

Heart Disease

  • Heart disease refers to a range of conditions affecting the heart, including diseases of the blood vessels (coronary artery disease), heart rhythm problems (arrhythmias), heart infections, and heart defects present at birth (congenital heart defects).
  • Lifestyle factors such as unhealthy diet, lack of exercise, smoking, and excessive alcohol can increase the risk of developing heart disease.
  • Symptoms of heart disease can include fatigue, shortness of breath, irregular heartbeat, swollen feet or ankles, and chest pain.