Cells, Tissues & Organs

Activities to try

1. 1

   Zoom along one example: body to cell and back

   Why it works: The four levels (cell → tissue → organ → organ system) form a nested hierarchy of increasing scale; a familiar organ like the heart is ultimately built from billions of tiny cells.

   1. Start by looking at the whole body, then move into the circulatory system, then to the heart, then into muscle tissue, then into a single muscle cell shown as if under a microscope.
   2. At each level, name the level and say how it relates to the level above and below it (e.g. 'muscle tissue is made of many muscle cells and forms part of the heart').
   3. Reverse the journey, zooming OUT from a single muscle cell up to the whole circulatory system, so the levels are seen to nest and combine both ways.
   4. Use a 'how many cells in your body?' reveal to land the idea that the body has trillions of cells, each too small to see without a microscope.
   5. State in your own words that the heart is not made of 'special heart stuff' but is built from tissue, which is built from billions of tiny cells.
2. 2

   Build it up: assemble the levels and place new examples

   Why it works: Each level is built by combining many of the level below, an organ system is several organs working together, and any body part — not just blood — can be placed on the ladder and traced back to cells.

   1. Combine many similar cells to form a tissue, several tissues to build an organ, and several organs into an organ system, so the COMBINE direction is seen explicitly, and note that an organ system is several organs working together, not a single organ.
   2. Take a new example (a nerve cell, the stomach, blood, skin) and place it at the correct level on the ladder.
   3. For a chosen organ, build the chain yourself: e.g. for the stomach or lungs, say which cells form which tissue, which tissue forms the organ, and which system the organ belongs to.
   4. Decide whether a part of the body (such as skin or bone) is made of cells, and justify your answer.
3. 3

   Consolidation and diagnostic check

   Why it works: A full understanding both orders the levels correctly AND explains how each level is built from the one below, transferable to a new organ.

   1. Order the four levels from smallest to biggest: cell → tissue → organ → organ system.
   2. Categorise a set of examples (nerve cell, stomach, blood, circulatory system) by their level.
   3. Answer the diagnostic: 'Your heart is an organ. If you looked at it closer and closer with a stronger and stronger microscope, what is it actually made of? Put organ, cell, tissue, organ system in order from smallest to biggest, and explain how each one is built from the one before it.'
   4. Extend to a probe: make the same build-up chain for the stomach or the lungs; explain why you can't see a single cell just by looking closely; say whether skin is made of cells too.