Primary Heart Dissection Lesson

Primary Heart Dissection Lesson

Welcome to our Heart Dissection Lesson aimed at Primary School students.

We have a heart dissection video demonstrating the methodology of the classroom dissection of a pig’s heart.  We have included a lesson plan and risk assessments that can be downloaded or simply reviewed here.

We hope to guide pupils through discovering as much as they can from the heart!

Aim: To explain how the structure of the heart is related to its function.
Year 6 Science Programmes of study statutory requirements:

Pupils should be taught to Identify and name the main parts of the human circulatory system, and describe the functions of the heart, blood vessels and blood


  • Place heart in dissection tray. The left side of the heart, with the thicker wall, should be to the right as you look at it.
  • The coronary arteries run across the front surface of the heart.
  • The interventricular sulcus is the main groove running down the surface of the heart that will identify the separation between the two ventricles.
  • Trace the sulcus up to the top of the heart and try to find where it comes from the aorta. You may need to carefully trim some fat away.
  • The aorta will be the thickest walled vessel since it pumps blood under pressure out of the heart to the rest of the body.
  • Gently press and squeeze the two sides of the heart and identify the two atria compartments at the top and the two ventricles at the bottom, and feel the differences in the wall thicknesses.
  • Use your scalpel to pierce the left atrium wall and use the scissors to cut down the heart from the left atrium to the left ventricle in a straight line using the interventricular sulcus as a guide.
  • Open up the left atrium and the left ventricle to the apex of the heart.
  • Trace where the aorta leaves the left ventricle and spot the valve in the aorta.
  • Cut open the right side of the heart in the same way as the left.

Teaching Notes:

  • The heart is an organ that pumps blood around the body in a double circulatory system.
  • The right ventricle pumps blood to the lungs where it collects oxygen. The right ventricle doesn’t need a thick muscle wall.
  • The left ventricle pumps blood around the rest of the body. The left ventricle has a very thick muscle wall.
  • Blood flows into the pulmonary vein, to the left atrium, left ventricle, then leaves the heart through the aorta to the body tissues.
  • From the tissues, blood travels to the vena cava, to the right atrium and right ventricle and then out of the heart via the pulmonary artery and back to the lungs to collect oxygen.
  • The function of the coronary arteries are to supply the heart muscle itself with oxygen and nutrient-carrying blood.

Observations to point out:

  • The two atria will have collapsed onto the top of the heart since they are no longer filled with blood.
  • The atria chambers can be easily stretched to show their thinness.
  • All four chambers will have the same capacity.
  • The heart strings attach valves to the ventricle walls and prevent the valves inverting. This helps to prevent any back flow of blood and maintain the blood flow in one direction only.
  • Samples for Schools Heart
  • Dissection tray
  • Scalpel
  • Scissors
  • Mounting needle
  • Paper towel