Skeletal System
7 October 2013
What do our bones reveal about us?
 Our health, past and current
 Trauma, past and current
 Age
 Gender
 Race
Significant concept:
Our bones are dynamic –
constantly changing
What do our bones reveal about us?
 Our health, past and current
 Trauma, past and current
 Age
 Gender
 Race
By the end of the mini unit,
you will know how our bones
change due to sex hormones,
age, and disease.
What are the functions of the bones?
1. Support - support and anchor the body and
organs
2. Protection – protect organs
Examples:
What are the functions of the bones?
1. Support - support and anchor the body and
organs
2. Protection – protect organs
Examples:
 Skull protects brain.
Ribs protect heart and lungs.
Vertebrae protect spinal cord.
3. Movement – bones serve as an attachment site
for muscles; muscles use bones like levers for
movement
What are the functions of the bones?
4. Storage – fat, calcium, and phosphorus storage
5. Blood cell formation – Red and white blood cells
develop within the red marrow of long bones and
flat bones
Classifying Bones by Shape
Sesamoid bones
are bones
embedded within
tendons. The
patella is the
largest example.
Sesamoid bones
are a type of short
bone.
Fun fact: The
number and size of
sesamoid bones
vary in different
people.
Classifying Bones by Shape
4 corners
Determine which
type of bone you
have & move to
the appropriate
corner of the
room.
Classifying Bones by Shape
4 corners
Examine all the
bones in your
group.
1. Do you all
agree about
the type?
2. Can you guess
which bones
any of them
are?
Structure of a Long Bone

The diaphysis is the shaft.

The epiphyses are the ends

Epiphyseal plates are plates
of hyaline cartilage found
near the ends of growing
bones. In adults, this
cartilage is completely
replaced by bone, forming
the epiphyseal line.
 The epiphyses are covered
with articular cartilage –
provides a smooth, surface
for joints.
Structure of a Long Bone

The diaphysis is covered with the
periosteum, a fibrous connective
tissue
 Inside the diaphysis is the
medullary cavity.
 In adults, the medullary cavity
is filled with yellow marrow
(function: to store fats)
 In infants, the medullary
cavity is filled with red marrow
(function: to produce blood)
 Fun fact: In adults, the yellow
marrow of the medullary
cavity can convert to red
marrow in cases of severe
anemia.
Structure of a Long Bone
Think, Pair, Share:
Name two ways the structure of
the long bone varies by age.
1) Infants have red marrow in
medullary cavity – converts
to yellow in adults
2) Growing individuals have
epiphyseal plates (cartilage);
adults have epiphyseal lines
Classifying Bones by Tissue Type
There are two types of bone tissue: spongy bone and
compact bone.
Classifying Bones by Tissue Type
There are two types of bone tissue: spongy bone and
compact bone.
Most bones contain both tissues types, in different
locations.
In irregular, flat, and
short bones, the
compact bone is
exterior and the
spongy bone is
interior.
Classifying Bones by Tissue Type
There are two types of bone tissue: spongy bone and
compact bone.
Most bones contain both tissues types, in different
locations.
Long bones are
mostly compact; in
long bones the
spongy tissue is
found only in the
ephiphyses (ends) of
the bones.
Microscopic Structure: Compact Bone
 Even compact
bone is not
solid! It has
many, many
channels for
blood vessels,
nerves,
nutrients and
wastes.
Microscopic Structure: Compact Bone
Basic unit of
structure: Osteon
 Consists of a
central
(Haversian)
canal and
lamellae (rings
of calcium salts)
 Between
lamellae are
cavities called
lacunae. The
osteocytes
(mature bone
cells) are found
in the lacunae.
Microscopic Structure: Compact Bone
Transport system:
 Blood vessels
and nerves grow
through central
canals (long
axis) and
perforating
canals (short
axis)
 Canaliculi (tiny
channels)
branch from
central canals to
all lacunae
Microscopic Structure: Compact Bone
Think, Pair,
Share:
Explain why an
excellent
transport system
is vital to the
functioning of
bone.
Microscopic Structure: Compact Bone
Microscopic Structure: Compact Bone
Microscopic Structure: Compact Bone
Osteon
lamellae
Microscopic Structure: Spongy Bone
All you need to
know is that
1) Spongy bone is
much less dense
2) Spongy bone
contains red
marrow, which
functions to
produce blood.
You Do:
Make a concept map, showing connections between
the following terms:
Group A Terms
• Lamellae
• Lacunae
• Osteocyte
• Central canal
• Perforating canal
• Canaliculi
Group B Terms
• Yellow marrow
• Red marrow
• Hematopoiesis
• Medullary cavity
• Spongy bone
• Compact bone
• Diaphysis
• epiphysis
Be prepared to share with the class!
You Do:
Make a concept map, showing connections between
the following terms:
Group A Terms
• Lamellae
• Lacunae
• Osteocyte
• Central canal
• Perforating canal
• Canaliculi
Group B Terms
• Yellow marrow
• Red marrow
• Hematopoiesis
• Medullary cavity
• Spongy bone
• Compact bone
• Diaphysis
• epiphysis
Be prepared to share with the class!
Closure
1. What were our objectives today and how well did
we meet them?
2. What learner profile trait did we focus on and how
did we use it?
3. How does what we learned today address our unit
question?
Exit Ticket
1. Identify 3 functions of bones.
2. Name two bones and describe their shape.
3. Draw and label picture of either the gross anatomy
(overall shape) of a long bone
OR
the microscopic structure of compact bone.