Survey of Anatomy and Physiology Chapter 6

The Skeletal
System:
The Framework
6


Skeleton’s FunctionSkeleton’s Function
• Provides support and structure
• Allows us to move
• Protects soft body parts
• Produces blood cells
• Stores minerals and fats


 Bones are primary components
of the skeleton
 Although composed of nonliving
minerals such as calcium and
phosphorus, bones are very much
alive, constantly building and
repairing themselves
Bones-IntroBones-Intro


 The word skeleton comes from
Greek word meaning "dried-up
body"
Bones-IntroBones-Intro


 Classified according to their shape
 Long bones: longer than they are wide and
can be found in arms and legs
General BoneGeneral Bone
ClassificationsClassifications


 Short bones: fairly equal in width and length
and found mostly in wrists and ankles


 Flat bones: thinner and can be either flat or
curved; plate like in nature and would include
skull, ribs, and breastbone (sternum)


 Irregular bones: like parts of jigsaw puzzle,
odd in shape; include hip bones and vertebrae


Figure 6-1
Various bone shapes.


 Periosteum (around bone)
 Tough and fibrous
connective tissue covering
bone
 Contains blood vessels,
which transport blood and
nutrients to nurture bone
cells, lymph vessels, and
nerves
 Acts as anchor points for
ligaments and tendons
Bone AnatomyBone Anatomy


 Epiphysis and diaphysis
 Epiphysis: bone end
 Diaphysis: region between
or "running through" two
epiphyses; also called
shaft
 Hollow region in
diaphysis (medullary
cavity or canal) acts as
storage area for bone
marrow


 Bone marrow
 Red marrow: makes
blood cells
 Yellow marrow:
high fat content; can
convert to red
marrow in emergency


Figure 6-2
Basic bone anatomy.
• Periosteum
• Epiphysis
• Diaphysis
• Medullary
• Red Marrow
• Yellow Marrow


PA/Instructor Asks:
A. Erythropoetin
B. Electrophoresis
C. Hemorrhage
D. Hemopoiesis


 Each unit or osteon
has mature bone cells
(osteocytes)
forming concentric
circles around blood
vessels
 Area around osteocyte
filled with protein
fibers, calcium, and
other minerals
Bone Tissue-CompactBone Tissue-Compact


 Osteons run
parallel to each
other; blood
vessels laterally
connect with
them to ensure
there is
sufficient
oxygen and
nutrients for
bone cells
Bone Tissue-CompactBone Tissue-Compact


 Trabeculae are
bars and plates
with holes in
the middle to
make the bone
lighter and
create space
for marrow to
form red blood
cells
Bone Tissue-SpongyBone Tissue-Spongy
Trabeculae


Figure 6-3
Comparison of compact and
spongy bone.
Compact
•Osteons with
•Osteophytes
•Connected by blood
and lymph vessels
Spongy
•Trabeculae formed
by bars and plates
•Hollow to give space
for marrow


 Bone is not perfectly
smooth; has variety of
projections, bumps, and
depressions
 Projections act as
points of
attachment for
muscles, ligaments,
or tendons
Surface Structure ofSurface Structure of
BonesBones


 Grooves and
depressions act
as pathways
for nerves and
blood vessels
Surface Structure ofSurface Structure of
BonesBones

 Ossification (osteogenesis): formation of
bone in the body
 Bones grow longitudinally to develop
lengthen and horizontally (wider and thicker)
so they can efficiently support body weight
and any other weight we support
Bone Growth andBone Growth and
Repair-OsteogenesisRepair-Osteogenesis


 Osteoprogenitor cells: nonspecialized cells
found in periosteum, endosteum, and
central canal of compact bones; can turn
into other types of cells as needed
Non-Specialized CellsNon-Specialized Cells


Repair-Cell TypesRepair-Cell Types


Bone GrowthBone Growth
and Repairand Repair
Osteoblasts actually form
bone and secrete a matrix
of calcium and phosphate


RepairRepair
Osteocytes mature bone cells that started as
osteoblasts; osteoblasts surround themselves
with matrix of calcium that helps them become
mature osteocytes


 Osteoclasts: believed to originate from type
of white blood cell called monocyte found in
red bone marrow; job is to tear down bone
material and help move calcium and
phosphate into the blood
RepairRepair


PA/Instructor Asks:PA/Instructor Asks:
A. Osteoblasts
B. Osteoclasts
C. Osteogenitor
D. Osteoporosis


 Bone development and growth begins in the
womb through intramembranous and
endochondral ossification
Bone GrowthBone Growth
and Repairand Repair


 Watch video “Skeletal System Bone
Formation”
 http://www.youtube.com/watch?v=PIT8zIWmSiI
RepairRepair


Figure 6-4
Endochondral ossification of
long bone.
• Begins before birth
• Periosteum surrounds the
“cartilage bone”
• Cartilage breaks down and
osteoblasts create spongy
bone in primary ossification
region


Figure 6-4
long bone.
• Meanwhile other
osteoblasts form
compact bone under
periosteum.
• Osteoclasts then break
down the spongy bone of
diaphysis (shaft) to create
medullary (middle) of bone


Figure 6-4
long bone.
Epiphyseal
plate is thin
band of
cartilage that
forms between
primary and
secondary
ossification
centers


 Epiphyseal plate (growth plate)exists as
long as bones need to lengthen and widen
RepairRepair


PA/Instructor Asks:PA/Instructor Asks:
A. Calcium
B. Vitamin D
C. Fluoride
D. Caffeine
*Read “Osteoporosis on Page 122


Figure 6-5
A normal bone compared to an
osteoporotic bone.


 Special form of dense connective tissue
that can withstand fair amount of flexing,
tension, and pressure
CartilageCartilage


 Flexible part of nose and ears are cartilage
CartilageCartilage


 Makes flexible
connection
between bones, as
between
breastbone and
ribs, allowing
chest to flex during
deep breathing
CartilageCartilage


 Acts as cushion
between bones;
articular cartilage
located on ends of
bones and acts as
shock absorber,
preventing ends from
grinding together
when you move
CartilageCartilage


Figure 6-6
Articular cartilage and synovial joint.
At this location, a
small sac, called
bursa, secretes
lubricant called
synovial fluid
Joints can wear out
and become inflamed
despite all this
protection, resulting
in arthritis or
osteoarthritis


Articulation/JointsArticulation/Joints
When two or
more bones
join together
they form a
joint or
articulation
When two or
more bones
join together
they form a
joint or
articulation


 Ligaments: tough, whitish bands that connect
from bone to bone; can withstand heavy
stress
Joints and LigamentsJoints and Ligaments


 Tendons are cordlike structures that attach
muscle to bone
Joints and TendonsJoints and Tendons


Types of JointsTypes of Joints


Figure 6-7
Types of Synovial joints.
Hinge: movement in ONE
direction; knee and elbow
Ball & Socket: lots of
movement; shoulder and
hip
Pivot: rotation only is
possible; neck or
radius/ulnar
Ellipsoid joint: two areas of
movement through same
bone; wrist, knuckles


Figure 6-7
Types of Synovial joints.
Gliding: flat & platelike that
slide black and forth;
scapula, wrists and ankles
Saddle: bone shaped like
saddle sits over another
like a horse; 1st
metacarpal
or thumb or the carpal
bone


Figure 6-8
Classification of joint movements.
Hyperextension: joint forced
to straighten beyond its
normal limits
Abduction: moving away
from body's midline
Adduction: moving toward
midline of body
Inversion: turning foot
inward toward other foot
Eversion: turning foot
outward away from opposing
foot


Figure 6-8
Supination: turning hand
palm up
Pronation: turning hand palm
down
Circumduction: combination
of movements in the circular
arm movement of a pitcher
Protraction: movement of
part forward
Retraction: motion of
drawing part backward
Rotation: when bone "spins"
on its axis


Figure 6-8
Flexion: bending a joint and
decreasing angle between
involved bones
Extension: straightening a
joint; angle between
involved bones increases
Plantar flexion: pointing toes
down
Dorsiflexion: bending foot up
toward the leg


Figure 6-9
The anterior and posterior
human skeleton.
Axial skeleton (80)
•thorax,
•spinal column,
•hyoid bone,
•bones of middle
ear,
•Skull
Appendicular (126)
•Arms
• legs
• hips
•shoulder


Figure 6-10
Bones of the skull.
Protects and houses
brain; has openings
needed for sensory organs
(eyes, nose, and ears)
Contains mouth, common
passageway for both
respiratory and digestive
systems
Fibrous cartilage allows
for some flexibility of bones
surrounding the brain


Figure 6-10 (continued)
Bones of the skull.


Figure 6-11
The bony thorax.
The Bones of chest form thoracic "cage" that
provides support and protection for heart,
lungs, and great blood vessels


Figure 6-11
The bony thorax.
Cage is flexible due to cartilaginous
connections that allow for movement during the
process of breathing


 Sternum (breastbone) is location for
performing chest compressions during
CPR, compressing heart between sternum and
bones of vertebrae
The Bony ThoraxThe Bony Thorax


Figure 6-12
The spinal column.
Also called
vertebral column;
super highway for
information
traveling to and
from the central
nervous system

 7 cervical vertebrae
in neck area
 12 thoracic
vertebrae in upper
back
 5 lumbar vertebrae
in lower back
 5 sacral vertebrae
midbuttock region
 1 tailbone or coccyx
is 3-5 small bones
fused
The Spinal ColumnThe Spinal Column


 At birth, vertebral column concave to front,
like a fetal position (primary curvature)
 Curvature changes as infant learns to hold its
head up, as well as starts to walk, curving in
opposite direction


 From two years onward,
vertebral column
develops secondary
curvature in neck,
primary curvature in
upper back, secondary
curvature in lower
back, primary curvature
in midbuttocks and
tailbone regions


Figure 6-13
Spinal disfigurements compared
to healthy spinal curves.


Figure 6-14
Bones of the upper and lower
extremities.
Appendicular
region consists of
arms and legs
These areas
perform most of the
body movement,
making them more
vulnerable to sport-
related injuries


Figure 6-14
Bones of the upper and lower
extremities.
Pelvic girdle different
for women than men
Women have greater
pubic angle, which
facilitates childbirth,
and broad girdle to
support extra weight of
child
Pelvis consists of:
ilium, ischium, pubis


 Fracture is any break in a bone
 Types of fractures
 Simple (closed): break without puncture to
skin
 Compound (open): fracture in which bone has
been pushed through skin
 Hairline: fine fracture that does not completely
break or displace bone (looks like hair on x-ray)
Pathology Connection: BonePathology Connection: Bone
Fractures and HealingFractures and Healing


 Types of fractures
 Greenstick: incomplete breaks, more common in
children
 Comminuted: when bone has been fragmented or
splintered


 Compound or open fractures are particularly
nasty because deep tissue has potential to be
exposed to bacteria once bone is set into place;
chance for infection in addition to break is
increased


 Bones take several weeks to heal; can only
heal normally if ends of bones are touching
 If bones are not touching (poorly aligned),
bone must be set (reduced)
 Traction may be used to treat fractures of
long bones
Watch video “Fracture Healing”
http://www.youtube.com/watch?v=TYNGyZrUXEk


 A somewhat frail 76-year-old female visits her
physician's office for an annual check-up. Her
social history shows she smokes a pack of
cigarettes a day and is a heavy coffee drinker.
Case StudyCase Study


 She has had several fractured bones in the
last five years that required medical attention.
During initial examination, measurements
show that the patient has lost
approximately an inch of height over the
past year. She has also lost several pounds
but states she still wears the same size
clothes.


 What possible bone disease do you think she
is exhibiting?
 Describe the bone changes in this condition on
a macro and cellular level (page 122)
 What treatments and/or lifestyle changes
would you suggest?

Survey of Anatomy and Physiology Chapter 6

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Survey of Anatomy and Physiology Chapter 6