Dissection of a long bone In this activity you will identify the structures of a long bone and answer the questions that follow. Materials Collect the following materials: a long limb bone cut longitudinally (from a butcher) a hand lens large piece of blank paper (butcher’s paper, A3 or any large sheet) digital camera marker pen reference/textbook pins, paper clips, blue tack, string or cotton anything that you can use or construct to link labels to structures. Instructions 1. Lay the paper on a flat surface and use your marker to divide the paper into two horizontal halves. 2. Lay the bone, cut surface downwards, in the centre of the top half of the piece of paper. 3. (a) Feel the outer surface (press it with your fingernail). Describe how it feels. (b) What is this fibrous outermost layer called? Using the marker pen, write the name of this layer on the paper and link it to the structure. © WestOne Services 2010 SCIENCE1437 1 (c) List the functions of this layer. 4. Look at both ends of the bone. In the space below describe what the surface feels like to touch. Then name and label the type of tissue that is covering this section. 5. While the bone is still in this position label the structures listed below: diaphysis epiphysis. 6. Take a photo of your labelled bone. 8. Move the bone to the lower half of the paper with the cut surface showing. 9. Locate the following structures and label them on the paper: medullary canal or cavity yellow marrow compact bone cancellous (spongy) bone. 10. Describe what the yellow marrow feels like to touch. What does this suggest about its composition? © WestOne Services 2010 SCIENCE1437 2 11. Use a hand lens to examine the bone in the shaft and compare it to the bone in the two ends. Describe the appearance of each one. You may wish to photograph the two sections if you have a zoom function on your camera that can show the differences clearly. 12. Where is compact bone the thickest? Suggest a reason why this is so. 13. Cancellous bone is also called ‘spongy’ bone. Is it soft like a sponge? Suggest a reason for this name. 14. Cancellous bone contains red bone marrow – how does this differ from the yellow marrow located in medullary canal. © WestOne Services 2010 SCIENCE1437 3 15. There is a chance that your bone may contain an epiphyseal cartilage. Find out where this is usually located and, if it is present, label it on your bone. If it isn’t present in your bone, draw a diagram in the blank box below to show the usual location of it. 16. Take a photo of your labelled bone. 17. It is important to safely dispose of the bone once you have finished your observations. Without refrigeration, harmful bacteria could grow on the bone tissue. Wrap it securely in newspaper and place it in a bin that will be emptied within 24 hours. If you are unsure when the next rubbish removal will occur, place the wrapped bone in a refrigerator until such time as you can dispose of it safely. Depending on where you are living, you could bury the bone in your yard – but if you have a dog this may not be wise! © WestOne Services 2010 SCIENCE1437 4