Includes all the bones of the body
 Also includes the joints the bones attach
to
 Without a skeleton, even a simple bump
on the head could injure vital organs
 The bones of the skeletal system are
stronger than steel


The entire skeletal system of an adult
weighs……
› Less than 10 kilograms

If you attempted to replace the human
skeleton with a steel skeleton that was
just as strong, it would weigh……
› About 400 kilograms!
› Still not as resilient as bone
Harder than reinforced concrete
 Lighter than stainless steel
 _________ is the near-perfect framework
for the human body
 The answer?

› BONE

This system has bones that come in 4
basic shapes:
› Long bones (femur)
› Short bones (wrist, ankle)
› Flat bones (skull, scapula)
› Irregular bones (vertebrae)
There are 5 ways the skeletal system
helps us
 These are:

› Support
› Protection
› Movement
› Storage
› Homeostasis
Primary job of the skeleton
 Without bones, we would collapse
 Skeletons are strong, but must also be
lightweight

Skeleton protects all internal organs and
fragile tissues (brain, eyes, heart, lungs,
spinal cord)
 Cranium protects the brain and eyes
 Ribs protect heart and lungs
 Vertebrae protects spinal cord

http://hes.ucfsd.org/gclaypo/skelweb/skel01.html
Bones provide structure for muscles to
attach (allowing movement)
 Tendons are tough inelastic bands that
attach muscle to bone

Bones have osteocytes
 These are cells that are able to store:

› Calcium
› Phosphorous
› Fatty acids

Bones regulate the amount of blood
calcium in our bodies
www.docstoc.com

This system has 2 distinctive parts
› Axial skeleton
› Appendicular skeleton

Let’s see what they’re all about!
Total of 80 bones
 Consists of the vertebral column, the rib
cage and the skull
 Transmits the weight from the head, the
trunk and the upper extremities down to
the lower extremities at the hip joints
 Helps in maintaining upright posture

http://www.clker.com/cliparts/6/8/8/2/1264138881213265971Axial_skeleton_diagram.svg.hi.png
Total of 126 bones
 Formed by the pectoral girdles, the
upper limbs, the pelvic girdle and the
lower limbs
 Has two primary functions

To make walking, running, and other
movement possible
 To protect major organs

› Responsible for digestion, excretion, and
reproduction
http://www.teachpe.com/anatomy/skeleton_appendicular180.jpg
Actually, BABIES have more bones
 At birth, you have about 300 bones
 As you get older, small bones join with
larger bones
 Adults end up having approx. 206 bones

YES
 Old bones are dry, dead, and brittle
 In the human body, however, bones are
very much alive
 Bones are a mixture of

› Strength
› Living cells (aiding in growth and self-repair)

Outer layer of hard or compact bone
› Called Pereosteum (contains blood vessels)
Inside is spongy bone (similar to
honeycomb, flexible)
 Some bones have bone marrow in the
middle (jelly-like) –location of new cells
being produced for the blood
 Bone cells can stay strong with the help
of the vital mineral Calcium

There are 2 types of bone marrow:
 Your body can actually convert yellow
bone marrow into red bone marrow if
there is an increased demand for red
blood cell production

› Red- building blocks of blood; where red
blood cells are produced
› Yellow- mostly consists of fat; place to store
fatty acids
http://hes.ucfsd.org/gclaypo/skelweb/skel01.html

There are 2 types of bone tissue:
› Compact bone- dense, smooth, and very
strong
› Cancellous bone- spongy and lightweight

Both tissues contain living cells
› Aids in repair if a bone is injured or broken
A broken bone is referred to as a fracture
 When a bone is broken, the bone
produces new cells to rebuild the bone
 Cells cover both ends of the broken
section of the bone to close up the
break


There are 7 main types of fractures of the
bone:
› Simple-bone doesn’t break skin
› Compound- broken ends do break skin
› Complete- 2 parts of bone
› Partial- broken bone, but not specifically 2 parts
› Impacted-broken ends are wedged together
› Comminuted-breaks into fragments
› Spiral- result of twisting bone; has rough edges
Need regular exercise to remain strong
 Drinking milk and eating other dairy
products, which contain calcium, help
bones harden

Every bone in the body forms a joint with
at least one other bone (only one
exception)
 With fewer joints, we would move like
robots
 There are 2 functions of joints:

› To hold bones together securely
› Give rigid skeleton mobility

Joints are classified in 2 ways:
› Functionally- focused on the amount of
movement allowed by the joint
› Structurally- fibrous, cartilaginous, and
synovial joints are based on what separates
the bony regions at the joints
Bones connected by fibrous tissue
 An example of this is the sutures of the
skull, where irregular edges of the bones
interlock and are bound tightly together
by connective tissue fibers
 This essentially allows no movement
 Syndesmoses- connecting fibers longer
than those of sutures ( joints have more
“give”)

The bone ends are connected by
cartilage
 Examples of this are:

› pubic symphysis of the pelvis
› invertebral joints of the spinal column (which
are connected by pads of fibrocartilage)
The articulating bone ends are
separated by a joint cavity that contains
synovial fluid
 Synovial joints have the most freedom
out of the other two types of joints

Skeleton has over 200 joints (when bones
come together)
 Ligaments are strong inelastic bands of
connective tissue that help hold bones
together at joints
 Where the bones come together at joints
there is a cushion of cartilage that helps
protect the bones
 Cartilage helps to prevent the bones from
rubbing against each other and wearing
down the bone


What does our Skeleton do for our
bodies?
› Support
› Protection
› Movement
› All of the above
(All of the above is CORRECT)

What holds bones together?
› Tendons
› Ligaments
› Cartilage
› Marrow
(Ligaments is CORRECT)

What attaches your muscles to bones?
› Ligaments
› Cartilage
› Tendons
› Cranium
(Tendons is CORRECT)

Why is bone marrow important?
› Marrow is very hard
› Marrow makes oxygen
› Marrow makes blood cells
› Marrow cleans your blood
(Marrow makes blood cells is CORRECT)
Image produced when a small amount
of radiation passes through the body
and strikes a sheet of sensitive film
placed on the opposite side of the body
 Bones contain calcium, therefore not
allowing much radiation through (which
causes bones to show up as white
images on X-ray film)
 Radiologists specialize in reading and
making sense of X-rays






Orthopedics is the medical specialty
responsible for treating entire skeletal system
In the US, orthopedic surgeons have typically
completed 4 years of undergraduate
education and 4 years of medical school
Then undergo residency training in orthopedic
surgery
The American Board of Orthopaedic Surgery
oversees the certification process for this
specialty
Many go on to further specialize in specific
areas, such as the spine, hand or sports injuries

Can you guess what it is?
Osteoporosis
Osteoporosis is the disease in which the
bones become weak and are more
likely to break
 People with osteoporosis most often
break bones in the hip, spine, and wrist

foreveryoungwithdeedeebuck.com
In the United States, more than 40 million
people either already have osteoporosis
or are at high risk due to low bone mass
 Osteoporosis can occur in both men and
women and at any age, but it is most
common in older women






Gender- women get osteoporosis more often
than men
Age- the older you are, the greater your risk of
osteoporosis
Body size- small, thin women are at greater risk
Ethnicity- white and Asian women are at
highest risk; Black and Hispanic women have a
lower risk
Family history- osteoporosis tends to run in
families; If a family member has osteoporosis or
breaks a bone, there is a greater chance that
you will too






Anorexia nervosa- this eating disorder can lead to
osteoporosis
Calcium and vitamin D intake- a diet low in calcium
and vitamin D makes you more prone to bone loss
Medication use- certain medicines increase the risk of
osteoporosis
Activity level- lack of exercise or long-term bed rest
can cause weak bones
Smoking- cigarettes have proven to be bad for
bones (and the heart, and lungs, too)
Drinking alcohol- too much alcohol can cause bone
loss and broken bones

There are several ways to avoid
osteoporosis:
› Eat a diet rich in calcium and vitamin D
› Exercise
› Don’t drink or smoke in excess
You might be wondering:
 “How does the skeletal system relate to
all of the other vital systems of the
human body?”
 To answer your question, it’s relationship
with each system is unique and
important to keep the body healthy

Indirect relationship with the “skin”
 Vital because the calcium keeps bones
hard and strong
 In the presence of sunlight, a vitamin D
precursor is produced in the dermal
capillary blood

Hormones acting individually and in
concert direct skeletal growth during
youth, and enhance (or impair) skeletal
strength in adults
 Growth hormone is essential for normal
skeletal growth and maintenance
throughout life

If we participate in weight-bearing exercise
regularly, our muscles become more
efficient and exert more force on our bones
 As a result, our bones stay healthy and
strong and increase their mass to assume
the added stress
 Regular exercise also stretches the
connective tissues binding bones to
muscles and to other bones, and
reinforcing joints

 The
hyoid bone (which is in
your throat) is the only
bone in the body not
attached to another bone
http://blog.corewalking.com/wp-content/uploads/2012/03/hyoid.gif
 The
smallest bones in the
body are the three bones
in the ear (anvil, stirrup,
and hammer)
http://ehealthmd.com/yms_images/middle_ear_bones_400.jpg
The
collarbone (scientific
name: clavicle) is the most
commonly broken bone in
the body
http://www.thedisabledlist.com/wp/wp-content/uploads/2011/02/broken-collarbone.jpg.gif
After
death, cartilage rots
faster than bone
This is why skulls have no
ears or nose






Essentials of Human Anatomy and Physiology by Elaine
N. Marieb
hes.ucfsd.org/gclaypo/skelweb/skel01.html
http://www.livescience.com/22537-skeletal-system.html
www.bodyworlds.com/Downloads/did_you_know.pdf
http://www.neok12.com/php/watch.php?v=zX66566f03
5b0b507b7a5245&t=Skeletal-System
http://www.youtube.com/watch?v=AMqMrDLBYro