SKELETAL SYSTEM
Casey Ferrara. Alicja Reczynska.
Rebecca Chang.
Composition and Function
 Composed of a network of hard and soft tissues
including bone, cartilage, ligaments, and
tendons.
 These tissues form the framework that provides
structural support to the body and gives it its
characteristic shape.
 Protects internal organs
 Facilitates movement by providing attachment
sites for muscles.
 Storage facility for minerals such as calcium
 Forming blood cells
 Maintaining an energy reserve of lipids
Axial Skeleton
Bones surrounding the midline (axis
of the body) forming the head and
trunk
Skull
Auditory Ossicles (ear bones)
Hyoid Bone
Vertebral Column
Sternum
Ribs
Skull – anatomically subdivided into 8
cranial bones and 14 facial bones
Auditory Ossicles - In the middle ear:
the maleus, incus, and stapes
These tiny bones transmit
vibrations from the eardrum to the
inner ear.
Hyoid bone- located in the higher part
of the neck and attaches the muscles
of the tongue.
 Sternum
(aka the
breastbone) consists of three
parts.
 Top: Manubrium Middle: Body or
Gladiolus
 Bottom: Xiphoid
Process
 Ribs – 12 pairs
First
7 pairs are attached to the
sternum by cartilage (considered
“true ribs”)
Next 3 pairs are indirectly attached
to the sternum by the cartilage of
the seventh pair ( called “false ribs”)
2 pairs do not connect to the
sternum at all ( known as the
floating ribs)
 Vertebral Column –Protect the spinal cord.
Provide site attachments for ribs and muscles
1st vertebra : atlas- moves head forward and
back
2nd vertebra : axis- moves head side to side
7 Cervical vertebrae (including the first 2
specific ones) – head movement
Below the neck are 12 thoracic vertebrae surfaces that join with the ribs
Below are 5 lumbar vertebrae - support a
tremendous amount of the body's weight
In adults, the five sacral vertebrae are fused
together to form the sacrum
The sacrum joins with the pelvic girdle to
form the pelvis
The remaining bones make up the coccyx
(aka tailbone)
Provides some movement
Part of the pelvic
Connected to several muscles and
ligaments
Connects hips
Appendicular Skeleton


Two pectoral girdles (shoulders)
Two pelvic girdles (hips)

Bones of the
upper and lower
extremities.
 Arms
 Legs
 Hands
 Feet
Long Bones




General Structure
 Long shaft called
diaphysis
 2 ends called
epiphysis
Examples : femur,
humerus
Function as a support
for movement
Contains yellow and red
bone marrow which
produce red blood cells
Joint Articulation




Where two bones come together
Three types
Immovable – Synarthrosis
 thin layer of fibrous connective
tissue. E.g. Skull
Amphiarthroses – Slightly movable
 hyaline cartilage or fibro cartilage
E.g. Intervertebral disks, ribs

Diarthroses - Freely movable
joints
 The ends of the opposing
bones are covered with
hyaline cartilage
 Joint cavity
 Dense fibrous joint
capsule.
 Ligaments that hold the
bones together
 The inner layer is the
synovial membrane that
secretes synovial fluid
into the joint cavity for
lubrication.
Osteoporosis
Osteoporosis

What is it?
 Osteoporosis is having a bone density
over 25% less than that of other
individuals of the same sex, age, and
race
 It is a decrease in bone strength and
bone mass
Osteoporosis
The etiology of osteoporosis is usually
associated with:
 a lack of certain sex hormones in
menopause/andropause
 Lack of calcium and vitamin D
 Inactivity or lack of exercise

Causes
 Some
see osteoporosis as
the result of “chronic
metabolic acidosis”, or an
excess acid load
Most at Risk
 Women
over fifty, or postmenopausal women are the
most at risk for contracting
osteoporosis
 Asian and Caucasian women are
at the most risk
Diagnosis





Osteoporosis can be easily diagnosed with a
routine x-ray
The American Medical Association, along with
The National Osteoporosis Foundation now
recommend a dual energy x-ray absorptiometry
scan to detect osteoporosis.
measures bone density in the hip and the spine.
5 to 15 minutes to perform
very precise
Symptoms
Surprisingly, bone loss is often without
noticeable symptoms.
 People may be unaware that they have
fallen victim to osteoporosis until they
suffer a break or fracture from a mild
slip or fall

Symptoms

As the disease progresses, the symptoms may include
 Loss of height (up to six inches)
 Tenderness of bones
 Neck pain
 Back pain
 Abdominal pain
 Rib pain
 toothaches
 Fatigue
 Spinal deformities
http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/17
156.jpg
http://www.bosco-system.com/images/osteoporosis.jpg
Treatment
CALCIUM CALCIUM CALCIUM!!!
 Vitamin D supplements are also
advisable
 Regular exercise is necessary to keep
the bones strong and avoid fractures

Treatments
However, recent studies show that
hormonal estrogen supplements
increase substantially a woman’s risk
for breast cancer, heart disease, and
stroke
 The risks now outweigh the benefits

Treatments


Evista- does not increase risk of cancer.
However, it does increase blood clots and hot
flashes
Actonel- inhibits cells that break down bone.
Intake must be carefully monitored because it
can lead to ulcers in the esophagus
The System
Connections
Skeletal System
Connections
 The skeletal system provides the
foundation for our body 
 It gives us structure and is our basic
framework 
 It also supports other systems, since all
of our body systems are interrelated and
interdependent 
Skeletal System
Connections
 Our skeleton supports our other systems
 It protects our vital organs
 It provides the attachments for our
muscles (muscular system)
Skeletal System
Connections
 The calcium released is an
essential component of the
nervous system
 Sensory receptors between the
joints provide the brain with the
necessary positioning
information
http://www.amersol.edu.pe/class09/_09tgupta/7t
h/science/Human/Images/humanskel.jpg
Ossification
What is it?
the synthesis of bone from cartilage
What
are the types of ossification?
Intramembranous ossification
Endochondral ossification
Intramembranous Ossification
Transformation of embryo cells into
bone
Mesenchyme: cells from an embryo…
are turned into connective tissue
Such as the skull
Endochondral Ossification
Gradual
change of cartilage into
bone during development
Regions of bone growth are called
ossification centers within the
cartilage from osteoblasts, actively
dividing bone forming cells.
Significance??
Ossification
allows the
development of bone within the
embryo
One such development is the skull
through intramembranous
ossification
development of bones, with the
use of proteins (collagen fibers),
calcium carbonate
Paget’s Disease
What
is Paget’s disease and who
does it affect?
Disorder relating to the breakdown
and formation of bones
causes bones to expand and weaken.
New bones grow weaker and larger
Occurs in men and women equally
over the age of 40, rarely diagnosed
under though.
Causes and What Bones Affected..
It’s a mystery!
Theories
include a virus in early
development of bones as well as genetics
These are the most common areas that
are affected:
Arm
Collar Bone
Leg
Pelvis
Spine
Symptoms and Tests
Bone Pain (may be severe and persistent)
Bowing of the legs and other visible deformities
Enlarged head
Fracture
Headache
Hearing loss
Joint Pain or stiffness
Neck pain
Reduced height
Skull deformities
TESTS:
Bone Scan
X-ray

Paget’s - images
Woman with bowed legs due to Paget’s
This is an image of a healthy bone (top)
compared to one with Paget’s disease.
So you have it…
what can you do now?
Drugs: help increase bone density
Biophosphonates
Calcitonin
Plicamycin
In severe cases:
Orthopedic surgery for specific
deformities

Rickets
What
is Rickets?
Bone disease affecting younger
children where bones are weak and
soft
Who does it affect?
Younger children
Causes
Lack of dietary calcium.
Lack of dietary vitamin D.
Insufficient sunlight exposure.
Vegetarian diets that aren’t nutritionally
balanced.
Dairy-free or lactose-free diets that aren’t
nutritionally balanced.
Exclusive breastfeeding without vitamin D
supplements for the baby.
Short bowel syndrome.
Kidney disorders, renal tubular acidosis.
Some liver disorders that affect absorption of
dietary fats.
Symptoms
Pain in bones
Increased risk of broken bones, including
spontaneous breaks that occur by themselves
without pressure or trauma.
Teeth failing to form or being slow to emerge.
Dental problems: deformed teeth or soft tooth
enamel.
Deformities of the skeleton: bowed legs, hunchback, scoliosis, abnormal skull shape.
Slowed growth and development.
Loss of muscle tone and strength.
Muscle cramps and spasms
Rickets
Treatment
Vitamin
D supplements,
especially specialized ones for
those who cannot transform the
Vitamin into its active from in the
body.
Surgery to fix bone deformities.
Increase in calcium.
CONCLUSION
 In conclusion, the skeletal system is the
best system
 Ever
 ………ever
 In the universe
 The
 End