Download Lab 04 - Skeletal Tissues and Bone Markings

Week 04 Lab
Skeletal Tissue and Bone Structure
LEARNING OUTCOMES:
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Identify the three types of cartilage tissue under the microscope, and relate their microscopic structure to
their respective functions.
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Become familiar with the basic shapes and markings of the bones of the skeleton.
Identify the major gross anatomical features of a long bone.
Identify bone tissue under the microscope and on anatomical models and describe its structure.
Contrast the roles of the organic and inorganic components of bone matrix.
ACTIVITY 1: Cartilage
In this activity, you will observe prepared microscope slides of hyaline cartilage, elastic cartilage, and
fibrocartilage.
Locations
Functions
hyaline cartilage
Forms most of the developing fetal skeleton;
found on the ends of long bones (articular
cartilages), between the ribs and sternum (costal
cartilages), and making up several respiratory
structures (nose and parts of larynx and trachea).
Support and reinforcement;
cushions and can resist stress.
In fetuses, it forms the framework
for what will become the bony
skeleton.
elastic cartilage
Found in external ear and epiglottis.
Maintains the shape of a structure
while providing more flexible
than hyaline cartilage; tolerates
bending better
fibrocartilage
Found in intervertebral discs, in the knee joint
(meniscus), in the joint where the two pelvic
joints meet (pubic symphysis).
Provides great tensile strength;
can withstand heavy
compression.
In Lab:
1. Obtain prepared slides of the three types of cartilage and find the following:
Hyaline cartilage
You should be able to find:
❍ chondrocytes living within lacunae
❍ matrix
❍ perichondrium – fibrous layer that surrounds the entire tissue
Elastic cartilage
You should be able to find:
❍ chondrocytes living within lacunae
❍ matrix
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dark-staining elastic fibers within the matrix
Fibrocartilage
You should be able to find:
❍ chondrocytes living within lacunae; usually stacked in rows
❍ matrix
❍ thick collagen fibers within the matrix
hyaline cartilage
elastic cartilage
fibrocartilage
ACTIVITY 2: General Bone Identification and Classification
In this activity, you will perform some basic bone identification and group bones based on their shapes.
In Lab:
1. Obtain a box of bones and a skull. Go through your box of bones and do the following:
❍ Use the figure on the following page to identify each of the bones in your box. All of the bones
should have a letter on them that corresponds to the letter on the box. If you find a bone that doesn’t
belong in your box, please tell the instructor.
❍ Using Fig. 6-1 (p. 171) in your textbook, sort the bones into piles based on their shapes: long, short,
flat, irregular, miscellaneous. Use the miscellaneous pile for groups of bones that come attached to
each other (the skull, for example) and therefore cannot be easily sorted.
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ACTIVITY 3: Bone Markings
In this activity, you will begin the process of becoming familiar with the different kinds of markings found
on bones.
Most bone markings fall into two basic categories: bumps, knobs, and projections that serve as attachment
sites for tendons and ligaments or form joints; or depressions, cavities, holes, and channels that are
passageways for blood vessels and nerves.
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In Lab:
1. Find the following examples of bone markings on the lab bones. Figure numbers refer to the textbook.
Underlined terms are general bone anatomical terms; they (and many others) can be found in Table 6-1
(p. 172) in the textbook.
a.
Sites of tendon and ligament attachment:
❍ ischial tuberosity (Fig. 8-8, p. 242)
❍ greater trochanter (Fig. 8-11, p. 244)
❍ spinous process (Fig. 7-18, p. 219)
b. Structures that form joints:
❍ head of humerus (Fig. 8-4, p. 237)
❍ acetabulum (Fig. 8-8, p. 242)
❍ facet on rib (Fig. 7-24, p. 227)
c.
Openings or channels
❍ foramen magnum (Fig. 7-5, p. 204)
❍ external acoustic meatus (Fig. 7-7, p. 206)
❍ obturator foramen (Fig. 8-8, p. 242)
ACTIVITY 4: Gross Anatomy of Long Bones
Most of the bones that we think of when we picture bones are long bones. In this activity, you will review
the basic features of a long bone’s gross anatomy.
In Lab:
1. Obtain a generously-sized long bone from your lab bones (a femur, tibia, or humerus will work fine).
2. Use Fig. 6-2 (p. 173) in the textbook to identify the following structures:
❍ diaphysis
❍ metaphysis
❍ two epiphyses (the distal and proximal epiphyses)
3. Obtain a preserved sawed bone. These bones are found in plastic bags. I recommend that you leave
them in their bags for this activity and that you wash your hands after handling them.
4. On these bones, you should be able to identify the following:
❍ the epiphysis
❍ the diaphysis
❍ the periosteum, which covers all of the bone’s external surfaces;
❍ the smooth articular cartilage on the ends of the bones
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(this will not be very obvious through the bag, but do your best)
❍ the medullary cavity within the diaphysis
❍ the yellow marrow inside the medullary cavity
❍ the spongy bone, with its trabeculae and marrow spaces, inside the epiphysis
ACTIVITY 5: Microscopic Anatomy of Compact Bone
In this activity, you will observe compact bone microscopically. You will also observe both baked and acidsoaked bones in order to appreciate the contributions of both the organic and inorganic components of
bone matrix.
In Lab:
1. Obtain a prepared slide of compact bone. This slide was prepared by simply grinding a chip off of a
larger bone and mounting it on the slide. That means that there are no other tissues present, nor are any
of the cells preserved.
2. On this slide, you should be able to identify the following:
❍ an osteon
❍ a central canal
❍ lamellae
❍ lacunae (which would have previously contained osteocytes)
❍ canaliculi
3. We also have an anatomical model of an osteon. See if you can find these structures on the model as
well.
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4. Obtain examples of both baked and acid-soaked bones. Both are unpreserved bones that come from
supermarket rotisserie chickens. Even though there’s no preservative here, it is recommended to leave
the acid-soaked bones in their bag (in case there’s any residual acid).
❍ Bones that are baked become dehydrated and essentially lose the organic component of their
matrix. What remains is the hard, brittle inorganic component (hydroxyapatite crystals).
❍ Soaking bones in acid dissolves the hydroxyapatites, leaving only the collagen fibers of the organic
component behind. Notice the flexibility that the collagen fibers provide the bone.
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