Physiology Lab
Name: _______________ Class: ______
Macroscopic and Microscopic Examination of Bone Tissue
Introduction: Bone is a connective tissue. Because of its composition and its microstructure, it
can withstand considerable stress without being compressed or shattered. Its ground
substance is packed with regular arrays of collagenous fibers and crystalline inorganic salts,
chiefly calcium phosphate. Bone calcium and phosphorous can be released to the body if
dietary intake does not meet the demand for these vital minerals.
The bones of the skeleton have several functions. Some bones contain red bone
marrow, the source of certain types of blood cells. Each bone has structural specializations
which provide sites for muscle attachment and surfaces for articulation with other bones and
which reduces mass without the loss of structural strength.
During this lab session you will examine the longitudinal and cross sections of a cow’s
long bone, probably the humerus or femur. These bones may feel greasy because the marrow
cavities are filled with fat, so wear gloves. We will also look at bone microscopically from
several different perspectives including, mature compact bone and mature spongy or cancellous
bone.
Part I: Gross Examination of Bones – Gloves required for this section.
1. Obtain samples of the bones from the side of the room. You are to write detailed
observations of what you see in these bones and answer the protocol questions. Follow
the specific directions below.
Longitudinal and Cross Sections:
2. Examine the epiphysis of the longitudinal section and find the articular cartilage. It will be
white and very smooth in a living animal and would also be lubricated with synovial fluid.
Find the epiphyseal cartilage. Note how it blends with cancellous bone which replaces it
during the growth process.
Elbow Joint:
3. The elbow illustrates the basic structure of a synovial joint and the limitations on
movement of a hinge joint.
4. It is best if you look at the cow elbow joint and then go and observe the elbow of the
human skeleton at the front of the room.
5. Compare your skeleton with the Figure at the end of the protocol. Be able to identify the
bones and prominent anatomical features. Orient your specimen so that it is in the
position it would be in, if the cow were standing. Do you have a right or a left elbow?
The best way to determine this is by observing that the shaft of the ulna runs along the
posterior-lateral border of the radius. So, is your ‘cow’ facing right or left?
6. Note that the humerus comes into contact with both the ulna and the radius, but that the
distal end of the ulna fuses with the radius. Compare this with the human skeleton at
the front of the room. Which arrangement is best for walking on four legs? Why?
Which is best for rotating the hand and carrying things?
7. Find the elbow joint. Now extend it. Note that it “locks” into the extended position; this
enables the cow to stand with minimal expenditure of energy. Notice that a part of the
ulna slips into the notch of the humerus when the joint is extended. This articulation
limits the degree to which the elbow joint can be extended. Now look for the ligaments
on either side of the humerus and observe how they attach to the ulna and radius. The
ligaments prevent the bones of the joint from being dislocated. If the ligaments are
damaged by stretching, the condition is called a sprain.
8. When you are done return these bones to the table at the side of the room. Wash the
dissecting trays and any tools with lots of soapy water. Dry all the equipment. Next we
will examine bones from a microscopic view.
Part II: Microscopic Analysis of Bone – Use the Real Anatomy software on your
computers to help you identify all the structures underlined for each slide. For each of the
types of bone views below, draw a detailed picture labeling all the underlined structures,
REMEMBER to also write down 2 bullet points of information from Real Anatomy for each
slide. For this lab, only 2 pictures per page.
1. Compact Ground Bone

Haversian systems are roughly cylindrical in structures that may branch. The
slide you are viewing is a ground section of mature human compact bone.
The center of each Haversian system contains a Haversian canal, which
travels through its long axis. This is surrounded by concentric layers of rings
of mineralized osteoid material, lamellae and a concentric arrangement of
lacunae, which house the bone cells, osteocytes. The lacunae appear as
dark oval structures. Though osteons vary in size, lacunae are smaller, more
numerous and are relatively uniform in size. Canaliculi radiate outwards from
the haversian canals to the lacunae, connecting osteocytes to osteocytes,
allowing materials to pass from cell to cell.
2. Cancellous (Spongy) Bone

Cancellous bone consists mostly of slender, trabeculae/spicules which
enclose irregular shaped and sized marrow cavities. At the edges, the
trabeculae merge with a very thin shell of compact bone. The trabeculae are
composed of parallel lamellae, scattered with osteocytes located in their
lacunae.
Assessment:
1. Introduction:

Research one bone disease, NOT OSTEOPOROSIS, and in 2 paragraphs
discuss causes of the disease, how it affects the overall functioning of the
skeleton and treatments of the disease.

You must include ONE CITATION (not your textbook) for this section!!!
Remember, full MLA format, not just the URL! Resource CANNOT be older
than 2005 and if no author or date of publication or website update date, then
you cannot use the reference!
2. Observations

Description of the longitudinal and cross sections of the cow bone and elbow
joint you observed – in detail. Remember – oh wow factor!!

Answer to questions found in protocol parts 5 and 6. Use full, descriptive
sentences.

For the two slides you observed today, discuss the how the microscopic
structural view relates to the macroscopic structure and overall function on
each specific bone type.
3. Labeled bone drawings.

There are to be 2 fully labeled drawings + 2 Real Anatomy bullet points per
drawing.
4. Analysis Question/Conclusion:

Elderly people often break bones under conditions that, for younger people
represent normal use. How do you explain for this observation?
Minimum of each of the following required: one paragraph long and one
citation required. Not your textbook!