SKELETAL SYSTEM
Functions of the Skeletal System
A. Bones are made of OSSEOUS TISSUE
FUNCTIONS:
1.Support
2. Protection
3.Body movement
4. Blood cell formation (bone marrow) - hematopoiesis
5. Storage of inorganic materials
(salt, calcium, potassium….)
B. ORGANIZATION
1. About 206
bones
2. 2 Main
Divisions –
Axial &
Appendicular
Classification of Bones:
BASED ON SHAPE
1.There is 2 basic types of osseus, or
bone, tissue:
a. COMPACT BONE – dense, looks smooth,
homogeneous
b. SPONGY BONE – composed of small
needlelike pieces of bone and open space
2. Long bones – longer than they are wide, have
shaft with heads at both ends; have mostly compact
bone
a. all limbs - ex, humerus and femur
3. Short bones – cube-shaped and contain
mostly spongy bone.
a. Wrist and ankle
4. Flat bones – thin, flattened, usually curved.
a. Skull, ribs, sternum are flat
5. Irregular bones– do not fit into another
category
a. Vertebrae
Types of Bone Tissue
1. Compact (wall of the diaphysis)
2. Spongy (cancellous, epiphysis) - red marrow
Inside the Long Bone
1. Medullary Cavity
– hollow chamber filled with bone
marrow
2. Red Marrow - (red
blood cell formation)
3. Yellow Marrow (fat replaces much of the red marrow
in diaphysis throughout childhood )
4. Endosteum– lining of
the medullary
BONE STRUCTURE – 5 PARTS of a Long Bone
1. Epiphysis – on each end
2. Diaphysis – main body/shaft
of bone
3. Articular Cartilage –
on ends for joint movement
4. Periosteum – outer covering
5. Medullary cavity – hollow
chamber within diaphysis that
connect to spaces in spongy
bone. Filled with bone
marrow.
* Assignment
– Coloring of a Long
Bone
Structure of a Long Bone
Figure 6.3a-c
Review the Structure of a
Long Bone
Matching quiz at
http://www.mhhe.com/biosci/a
p/holehaap/student/olc2/chap
07matching01.html
Axial Skeleton
1. Head, neck, trunk
a. Skull
b. Hyoid Bone
c. Vertebral Column
d. Thoracic Cage
(ribs, 12 pairs including true
and false and floating ribs)
e. Sternum
Hyoid Bone – closely related to mandible and temporal bone
1. Unique that it is the only
bone of the body that
does not articulate
directly with any other
bone.
2. Serves as a movable
base for the tongue and
attachment point for neck
muscles that raise and
lower the larynx when we
speak and swallow.
3. Is more prominent in
males than females.
Appendicular Skeleton
•Limbs & Bones that connect to the
o Pectoral Girdle (shoulders)
o Pelvic Girdle (hips)
Microscopic Structure – of Bone Growth and Development
1. MATRIX - where the bone cells live
2. OSTEOCYTES - mature bone cells, enclosed in
tiny chambers called LACUNAE
3. OSTEOCYTES form rings (LAMELLAE) around
a HAVERSIAN CANAL which houses blood vessels
4. Osteocytes are linked by CANALICULI
5. Haversian Canals are linked by VOLKMAN's
CANALS
Compact Bone
BONE
COLORING!
Test Yourself
Find the...
Haversian Canal
Volkman's Canal
Lamellae
Spongy Bone
Compact Bone
BONE DEVELOPMENT & GROWTH
1.Intramembranous bones –
are flat, ex. Skull
2. Endochondral bones –
all other bones
3. ALL BONES start as
hyaline cartilage, areas
gradually turn to bone (through the
process of OSSIFICATION)
4. PRIMARY ossification center
(shaft)
5. SECONDARY ossification
center(ends)
Bone Development & Growth
6. EPIPHYSEAL
DISK (growth plate) is a
band of cartilage
between the epiphysis
and diaphysis
7. These areas increase
bone length as the cells
ossify
8. Cartilage becomes
OSTEOBLASTS become
OSTEOCYTES
RESORPTION
a. Bone tissue is constantly being replaced as special
cells called OSTEOCLASTS dissolve bone tissue from
within the medullary cavity and releases minerals- a
process called RESORPTION.
b. At the same time new bone tissue is being added to the
outside of the bone.
Assignment: Coloring of an Aging Hand
Bone Growth
Bone Growth
Function of Joints
1. Hold bones together securely
2. Give the rigid skeleton mobility.
Types of Joints (Also called Articulations!)
1.Synarthrotic (not
moveable, ex. sutures
of the skull)
2.Amphiarthrotic
(slightly moveable,
ex. vertebrae)
3. Diarthrotic (moveable
joint, ex. synovial joints
like knee or hips)
Synovial fluid - fluid within
the joints that helps to
lubricate
Types of Joints:
1. Ball and Socket
(example – shoulder/hip)
2. Hinge
(example – knee)
3. Pivot
(example – elbow)
4. Saddle
(example – fingers)
BONES OF THE SKULL (Lab Test)
1. Frontal 2. Parietal 3. Occipital 4. Temporal 5. Sphenoid 6. Maxilla 7. Mandible 8. Zygomatic -
More Bones of the Skull to know!
9. Lacrimal
10. Ethmoid
11. Nasal
12. External
Auditory meatus
13. Mastoid process
14. Styloid Process
15. Temporo-mandibular joint
16. Sagittal suture
17. Lambdoid suture
18. Squamous suture
19. Coronal suture
20. Foramen magnum
21. Mental foramen
TOPOGRAPHY OF THE SKULL
Foramen - refers to any tiny opening, nerves
and blood vessels leave this opening to
supply the face
Mental Foramen
Suture - refers to any connection between large
bones (in fetal skulls, these are called fontanels)
Fissure - any wide gap between bones
Sutures
1. Coronal - between frontal and parietal
bones
2. Lambdoid - between occipital and parietal
bones
3. Squamous - between temporal and
parietal bones
4. Sagittal - between parietal bones
Bones of the Skull & Sutures
Foramen Magnum
* Assignment: Skull Labeling
Figure 6.10
Figure 6.10
Fetal Skull
1. The adult skull
represents only 1/8 of
the total body length.
2. The newborn infant
skull is only 1/4 as long
as its entire body.
3. Areas of newborn’s
skulls are still hyaline
cartilage, called
fontanels. (until age 2)
4. The rhythm of the
baby’s pulse can be felt in
these “soft spots”
5. The largest fontanels are the
anterior fontanel and posterior
fontanel; which allows the skull
to be compressed slightly
during birth.
6. Allows the brain to grow and
develop in the womb and
infancy.
The Rest of the Bones
Vertebrae
Neck = cervical (C1 – C7)
Middle Back = thoracic
(T1 – T12)
Lower Back = lumbar (L1 –
L5)
Sacrum = 5 fused vertebrae
Coccyx = tailbone
Thoracic Cage
Pectoral Girdle
Bones of the Arm
a. Humerus – upper
arm
b. Ulna goes to
pinky (P-U or “UP”)
c. Radius goes to
thumb (RT)
Wrist Bones
For test:
a. Carpals
b. Metacarpals
c. Phalanges
Name the carpals for extra credit
on test.
Pelvic Girdle – Wider in females than males
Sacrum – 5 fused vertebrae
Bones of the Leg
Bones of the Ankle
For Test:
Calcaneous
Tarsals
Metatarsals
Phalanges
Assignment –
Skeleton Labeling
What you should have
on your “Mr. Bones”
labeling sheet!
https://youtube.googleapis.com/v/btMq9BYziIQ
Broken Bones – heal faster than ligaments or tendons because
they have a greater or richer blood supply
*A compound fracture is most dangerous.
1. Because it’s an open fracture that may result in a severe
bone infection (osteomyelitis), requiring massive doses of
antibiotics.
2. While a simple fracture is incomplete, not breaking the skin.
A simple fracture is sometimes called a “closed fracture”.
Fractures are treated by reduction.
Closed Reduction:
The bone ends are coaxed
back into their normal
position by the physician’s
hands.
Open Reduction:
Surgery is performed and
the bone ends are secured
together with pins or wires,
then immobilized by a cast
or traction for healing.
Abnormal Bone Conditions
1. BONE SPURS: abnormal growth. Can occur on any bone
(e.g. heel).
2. OSTEOPOROSIS: Increased activity of osteoclasts cause
a break down bone, and the subsequent fewer minerals in the
extracellular matrix make it fragile. The spongy bone
especially becomes more porous.
3. Men get it as well as women. What’s the best way to
prevent osteoporosis? Exercise! What does exercise do?
Makes bones bigger.
4. The most common bone used for a bone graft is the iliac
bone of the hip.
Osteoporosis
Figure 6.15
Arthritis
Rheumatoid arthritis is an autoimmune disease
which causes joint stiffness and bone deformity
Source: http://www.thetimes.co.uk/tto/public/article3233439.ece
ABNORMALITIES OF THE SPINE
1. SCOLIOSIS is a lateral curve in the spine
2. KYPHOSIS is a hunchback curve
3. LORDOSIS is a swayback in the lower region.
4. ANKYLOSIS is severe arthritis in the spine and
the vertebrae fuse.
SCOLIOSIS
LORDOSIS
ANKYLOSIS
Rickets – disease of children which bones
fail to calcify resulting in bone softening and
bowing of the weight-bearing bones of legs.
Is due to a lack of Vitamin D and calcium in
the blood.
Bursitis
Inflammation of the Bursa (fluid filled sac
surrounding the joint).
A bursa can become inflamed from injury,
infection (rare in the shoulder), or due to an
underlying rheumatic condition.
Bursitis is typically identified by localized pain or
swelling, tenderness, and pain with motion of the
tissues in the affected area.
Tendonitis
Sometimes the tendons become inflamed for a
variety of reasons, and the action of pulling the
muscle becomes irritating.
If the normal smooth gliding motion of your
tendon is impaired, the tendon will become
inflamed and movement will become painful.
This is called tendonitis, and literally means
inflammation of the tendon.
The most common cause of tendonitis is
overuse.
Carpal Tunnel Syndrome
Any condition that causes swelling or a change in position of
the tissue within the carpal tunnel can squeeze and irritate
the median nerve. Irritation of the median nerve in this
manner causes tingling and numbness of the thumb, index,
and the middle fingers, a condition known as "carpal tunnel
syndrome."
Gout
Gout is a disease that results from an overload of
uric acid in the body. This overload of uric acid
leads to the formation of tiny crystals of urate
that deposit in tissues of the body, especially the
joints.
When crystals form in the joints it causes
recurring attacks of joint inflammation (arthritis).
Chronic gout can also lead to deposits of hard
lumps of uric acid in and around the joints and
may cause joint destruction, decreased kidney
function, and kidney stones.
GOUT
Leukemia
Leukemia is cancer of the blood cells. It starts in the
bone marrow, the soft tissue inside most bones. Bone
marrow is where blood cells are made.
When you are healthy, your bone marrow makes:
･White blood cells, which help your body fight infection.
･Red blood cells, which carry oxygen to all parts of your
body.･Platelets, which help your blood clot.
When you have leukemia, the bone marrow starts to
make a lot of abnormal white blood cells, called leukemia
cells. They don't do the work of normal white blood cells,
they grow faster than normal cells, and they don't stop
growing when they should.
Bone Marrow Biopsy
FUN FACTS ABOUT BONES
Bone is made of the same type of minerals as
limestone.
Babies are born with 300 bones, but by adulthood
we have only 206 in our bodies.
The giraffe has the same number of bones in its
neck as a human: seven in total.
The long horned ram can take a head butt at 25
mph. The human skull will fracture at 5mph.
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