Name __________________________________
Looking Inside Bone – 75 Informal Points (& 2 Formal for Bone Dissection)
Introduction
Bones are a remarkable example of engineering, combining lightness, flexibility and incredible strength. Bone provides a tough,
flexible frame for the human machine. Pound for pound, bone is actually stronger than concrete. But remember, bone is living
tissue. Cells and protein fibers are wrapped inside layers of hard mineral salts. These cells are hard at work, constantly remodeling
and replacing old or damaged bone. Blood vessels and nerves bring needed nutrients and signals to the cells in this hard matrix.
All of these structural components allow bone to withstand tremendous amounts of stress and protects the internal organs from
damage and injury.
To understand how bone is able to protect our body, we must look at the anatomy of this calcified tissue. How does the structure of
bone relate to its ability to withstand stress? In this activity, you will dissect a long bone and observe the key structures that
contribute to bone’s unique architecture. You will then look deeper into the chemical structure of this tissue as you view prepared
slides of both compact and spongy bone.
Procedure
1. Research the four main types of bone – long, short, flat and irregular. Fill in the table below with your
findings.
Bone Type
Long
Short
Irregular
Description
Example(s)
Hard, dense (compact) bones that provide strength, structure, and
mobility.
Femur
Bones that are as wide as they are long. They provide support and
stability with little to no movement.
Patella, Tarsus
Serve various purposes in the body, such as protection of nervous tissue
(such as the vertebrae protect the spinal cord), affording multiple anchor
points for skeletal muscle attachment (as with the sacrum), and maintain
pharynx and trachea support, and tongue attachment (such as the hyoid
bone)
Examples given in blue
2. Use the internet to help you research and then identify the external features of long bone listed below.
Fill in the table with your findings.
External
Bone
Feature
Description
Spongy cancellous bone covered by a thin layer of compact bone.
Epiphysis
Diaphysis
The main part, or shaft, of a long bone. It usually contains the one marrow and adipose tissue
(fat.)
Firm, yet soft and flexible connective tissue found between bones or between bones and joints.
Cartilage
Dense, fibrous, membrane covering the surface of a bone.
Periosteum
Compact
(Cortical)
Bone
Spongy
(Cancellous)
Bone
Medullary
Cavity
Solid bone with only tiny spaces.
A network of irregularly shaped sheets of bone (trabeculae). The trabeculae are only a few cell
layers thick. The spaces between the trabeculae contain the bone marrow.
The central cavity of a bone shaft where the red bone marrow and yellow bone marrow (adipose
tissue (fat)) is stored; also known as the marrow cavity.
Bone marrow where red blood cells, platelets and most of the white blood cells are made.
Red Bone
Marrow
Some white blood cells are made here, but the yellow bone marrow is mostly fat (adipose tissue)
Yellow Bone
Marrow
3. In the space below draw a cross section of a bone. Include and label all parts listed in the table in #3.
4. Long Bone Dissection: In groups of three obtain a section of cow long bone and a set of dissecting tools
from your teacher. Place the bone in a dissecting tray or on a covered lab bench. Cow and human long
bones have a similar general structure.
5. Use the forceps to remove a piece of the periosteum from the outer surface of the bone. You may find
fragments of tendon, ligament or muscle adhering to the periosteum. In the space below, describe the
composition of this membrane as well as its function.
6. Use the dissecting probe to compare the texture of compact and spongy bone. Poke into each tissue and
feel the composition of each type of bone. Describe the difference in the space below.
7. Note the location of spongy and compact bone in the epiphysis and the diaphysis.
8. Examine the epiphysis and find the articular cartilage; this tissue is slippery.
9. Carefully scoop out the fat from the medullary cavity. In the space below describe the composition of this
marrow as you remove it from the bone. Make sure to note the presence of any blood vessels or nerves.
10. Identify where red bone marrow would be located in your cow bone in the space below.
11. Get a closer look at compact and spongy bone structures by viewing each type of tissue under the
microscope. (Note: you may also use the internet to look up images for each.) Compact bone may
appear rock solid, but it actually contains many holes for cells, nerves and blood vessels. Draw each in
the table below:
Compact Bone
Magnification: ______________
Spongy Bone
Magnification: ______________
12. Observe a cross-section of calcified compact bone. Use colored pencils to draw and label the following
structures as they appear using the 40X objective, or by looking at an image from the internet. Label the
Haversian canal, osteocyte (mature bone cell) in lacuna, and canaliculi. Then, fill in the table below to
describe each.
Calcified Compact Bone
Magnification: ______________
Calcified
Bone
Feature
Description
Part of the bone that contains the blood vessels
Haversian
Canal
Scientific term for a bone cell
Osteocyte
Small channels or ducts found in bone
Canaliculi
13. Observe a cross-section of spongy bone. Draw and label the following structures as they appear using
the 10X objective, or by viewing an image from the internet. Label the bone marrow and the bony
trabeculae.
Spongy Bone
Magnification: ______________
Spongy
Bone
Feature
Bone
Marrow
Bony
Trabeculae
Description
Red bone marrow makes red blood cells, platelets, and most white blood cells; white bone marrow
makes some white blood cells but is mostly fat
A network of irregularly shaped sheets of bone (trabeculae). The trabeculae are only a few cell
layers thick. The spaces between the trabeculae contain the bone marrow.
Conclusion Questions
1. Matt was playing football when he was tacked, knocked to the ground, and piled upon, knocking him
unconscious. What properties of bone prevented Matt from breaks and damage to internal organs?
Bones are hard so that they form a sturdy protection around internal organs. When the body is hit or under
pressure the bones absorb the shock or break instead of the internal organs that would be more severely
damaged.
2. What role did Matt being knocked unconscious play in his body’s ability to resist damage? (Ie, why might
being knocked unconscious be beneficial in this case?)
When unconscious the muscles relax and are not tense. If Matt was unconscious before falling his relaxed
muscles would allow him to fall more gently and not hit the ground so hard. Also, being unconscious
reduces the panic and anxiety that go along with getting injured, calming the body systems and allowing
them to rest and heal.
3. What type of fibers or minerals do you find in the extracellular matrix of bone? How does this composition
relate to the properties of bone?
Calcium makes them strong.
4. What aspects of bone’s structure make it stronger than concrete? Think about the engineering design of
bone. Use the terms tensile strength and compressional strength in your answer.
Similar in that steel rebar allows concrete to resist stretching forces, while the cement resists
compression
Bone structure is somewhat similar to reinforced concrete that contains structural metal
reinforcement rods or bars. These metal reinforcements are commonly called rebar. Protein
strands make up the rebar of bone. Calcium and phosphorus mineral crystals deposited around
the protein strands are somewhat like the concrete poured around the rebar in reinforced
concrete. The protein strands provide the tensile strength that holds everything together and the
minerals provide the solid structure. If bones were made only of protein, they would be too
flexible. If bones were made solely from minerals, the skeleton would be too brittle.
5. How do red bone marrow and yellow bone marrow differ in function?
Red bone marrow makes red blood cells, platelets and most white blood cells. Yellow bone marrow makes
some white blood cells but is mostly adipose tissue (fat.)
6. Explain how the structure of spongy bone helps reduce the overall weight of bone.
It is less dense so it less compact, making it lighter.
7. Describe at least two ways bone functions in protection of the human body.
Ribs protect lungs and heart. Skull protects brain.