Download Physiology of the Skeletal System

Factoids
• The human hand has 27 bones; your face has 14!
• The longest bone in your body? Your thigh bone,
the femur -- it' s about 1/4 of your height. The
smallest is the stirrup bone in the ear which can
measure 1/10 of an inch.
• Did you know that humans and giraffes have the
same number of bones in their necks? Giraffe
neck vertebrae are just much, much longer!
• You have over 230 moveable and semi-moveable
joints in your body.
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Tornado Boy
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Skeletal System
• Bones are made of several
tissues
• Primarily made of collagen and
hydroxyapatite Ca10(PO4)6(OH)2
• 206 bones in the human body
(over 300 at birth).
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Functions of Skeletal System
• SUPPORT: Hard framework that supports and anchors
the soft organs of the body.
• PROTECTION: Surrounds organs such as the brain and
spinal cord.
• MOVEMENT: Allows for muscle attachment therefore
the bones are used as levers.
• STORAGE: Minerals and lipids are stored within bone
material.
• BLOOD CELL FORMATION: The bone marrow is
responsible for blood cell production.
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Skeletal System Organization
Skeletal System Organization
• Axial skeleton
• Appendicular skeleton
– Skull and bones that support it
– Includes vertebra and ribs
– 80 bones
• head
• neck
• trunk
– Limbs
– 126 bones
• upper limbs
• lower limbs
• pectoral girdle
• pelvic girdle
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Maxilla
Mandible
Vertebral column
First 7 - cervical
Next 12 - thoracic
Last 5 – lumbar
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Bone Classification
Sesamoid
Long
Bones
(a)
Flat
Short
Bones
Bones
(c)
(b)
Irregular
(Round)
Bones
–
femur,
tibia,
– cranium,
Bones
(d)of the
- bones
humerus,
ilium,
(e)
- wrist
patella
and ankle
–fibula,
vertebrae,
Illium
radius,
and
sternum,
ribulna ,
sacrum,
metacarpals,
cage,
sacrum
hyoid
metatarsals,
and scapula and
phalanges
Ischium
Pubis
Ribs (12 pairs)
First 7 - true
Next 5 - false
(Last 2 - floating)
Talus
Calcaneus
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Features of a Long Bone:
Epiphysis: Ends of the
bone.
Diaphysis: The shaft of
the bone which surrounds
the medullary cavity.
Articular Cartilage:
Cushions the ends of the
bones and allows for
smooth movement.
Epiphyseal Plate:
Areas made of cartilage
allowing for the growth of
the bone.
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Bone Structure
• Periosteum – hard outer covering
– Cells for growth and repair
• Compact bone – hard strong layer
– Bone cells, blood vessels, protein with Ca and P
• Spongy bone – at ends of long bones
– Has small open spaces to lighten weight
• Marrow cavity – hollow in middle of long bones
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Bone Marrow
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Hematopoiesis
• Occurs in cavities with red marrow
• Medullary Cavity
• Red marrow – produces blood cells and
clotting factors
– Found in humerus, femur, sternum, ribs,
vertebrae, pelvis
– Produces RBC 2 million per second
– In children contains read marrow and is
hematopoietic
– In adults the red marrow is replaced by fat –
yellow marrow (not hematopoietic)
• Hematopoiesis in Adults
• Yellow marrow – stores fat
– Red marrow in spaces of spongy bone
– Head of femur and humerus
– Some flat bones: sternum, pelvic bone
– Found in many bones
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Bone Structure
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Compact & Spongy Bone
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Haversian canals

• Bones are composed
of connective tissue,
chemicals, and fats
• Solid outer layer compact bone
– Composed of osteons
• Volkmann’s canals
› allow the passage of blood
vessels, lymphatic vessels,
and nerve fibers.
› Surrounded by layers of
bone called a lamella.
Above: Note the relationship btwn the
compact and spongy bone.
– Perpendicular to the
haversian canals.
– Connect the blood and
nerve supply in the
periosteum to those in the
haversian canals and the
medullary cavity.
Below: Close up of spongy bone.
osteon
• An inner layer of
spongy bone
– a honeycomb of flat,
needle-like projections
called trabeculae.
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
osteoblasts
Osteoblasts
› Bone building cells
› Synthesize and secrete
collogen fibers and other
organic components of the
bone matrix
› Initiate calcification
› Found in the periosteum and
the endosteum
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•
Bone matrix
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›
›
›
•
 Ossification
› Formation of bone by
osteoblasts.
› Cells surround themselves by
matrix.
Osteocytes.
•
Mature bone cells.
Osteoblasts that have
become trapped by the
secretion of matrix.
Responsible for
maintaining the bone
tissue
Lacunae
›
spaces occupied by
osteocyte cell body
Canaliculi
›
canals that allow for
nutrient filled liquid to fill
the lacunae
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6-22
Why is there a depression underneath the osteoclast?
What advantage might a ruffled border confer?
What is the name of the third cell type shown here?
What do you think the tan material represents?
Osteoclasts
Cells that ecretes digestive enzymes to digest bone matrix
bone resorption
Concentrated in the endosteum.
On the side of the cell that faces the bone surface,
ruffled border.
Pumps out hydrogen ions
Create an acid environment that eats away at the matrix.
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www.academic.pgcc.edu/~aimholtz/AandP/LectureNotes/ANP1_Lec/Skeletal/
BoneTissue.ppt
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Bone Development
• Initial skeleton of cartilage in infants
• Replaced with bone by osteoblasts
• More than 300 bones at birth – fuse to 206
• Always growing and breaking down
– Osteoblasts – form new bone cells
– Osteoclasts – break bone cells down
– Osteocytes – mature bone cells
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Fractures
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Types of Fractures
Types of Fractures
•
•
•
•
•
•
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green stick
fissured
comminuted
transverse
oblique
spiral
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Broken Bones
Fracture Repair
Regrowth of bone:
–Spongy bone forms in first few days
–Blood vessels regrow and
spongy bone hardens
–Full healing takes 1-2 months
• Hematoma- blood clot in space between edges
of break
• Fibrocartilage callus- begins tissue repair
• Bony callus- osteoblasts produce trabeculae
(structural support) of spongy bone and replace
fibrocartilage
• Remodeling- osteoblasts build new compact
bone, osteoclasts build new medullary cavity
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Mechanics of Movement
• Tissues and Structures Involved
– Muscle
– Nerve
– Bone
– Cartilage
• What are Tendons & Ligaments?
• Types of Joints
• Mechanics of Joints
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Functions of the Skeletal System
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HOW DOES MOVEMENT HAPPEN?
Muscles PULL on Tendons
to Move Bones at Connections
called Joints or Articulations
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Tendons
Ligaments
• Tendons are structures that connect bone to muscle,
muscle to muscle, or bone to bone

Made up of tendon
tissue (connective
tissue)

Can have various
shapes
 Ligaments
connect bone-tobone or reinforce
joints--they are
made up of
tendonous tissue
as well

Typical is cord-like
tendon of biceps
Typical are knee
ligaments
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Frolich, Human Anatomy, Mechanics of Movement
Joints
Frolich, Human Anatomy, Mechanics of Movement
Functional Classification
The amount of movement the joint allows
• Usually, but not always allow for movement
• Formed from various connective tissues
– Fibrous
– Cartilaginous
– Synovial (most complex--typical limb joints)
Synarthroses
immovable joints
Amphiarthroses
slightly moveable joints
• Functions of joints
– Hold bones together
– Allow for mobility
Diarthroses
freely moveable joints
• Ways joints are classified
– Functionally
– Structurally
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Frolich, Human Anatomy, Mechanics of Movement
Frolich, Human Anatomy, Mechanics of Movement
Fibrous Joints
Structural Classification
Bones united by fibrous tissue –
synarthroses or largely immovable.
Fibrous joints
Generally immovable
Fibrous tissue separate the boney region at the joint
 Skull
Cartilaginous joints
 Bones tightly bound
Immovable or slightly moveable
Cartilage separates the boney regions at the joint
by minimal fiber
 Syndesmosis
 Longer connecting
fibers
 Joint has more give
Synovial joints
Freely moveable
The boney regions of the joint are separated by a
space
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Frolich, Human Anatomy, Mechanics of Movement
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Frolich, Human Anatomy, Mechanics of Movement
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Cartilaginous Joints
Synovial Joints
Mostly amphiarthrosis
Diarthroses – movable joint
Bones connected by cartilage
Slightly movable
Most common joint in the body
 Articulating ends of bones are
covered with hyaline cartilage
Pubic symphysis
Intervertebral joints
Hyaline cartilage unites bones
Epiphyseal growth plates
Costal cartilage-sternum
 Enclosed by a capsule of fibrous
connective tissue lined with synovial
membranes
 Joint cavity is filled with synovial
fluid for lubrication
 Ligaments reinforce the joint
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Frolich, Human Anatomy, Mechanics of Movement
Typical Synovial Joint
Frolich, Human Anatomy, Mechanics of Movement
Structures Associated with the
Synovial Joints
Bursae – flattened fibrous sacs
Lined with synovial membranes
Filled with synovial fluid
Not actually part of the joint
Tendon sheath
Elongated bursa that wraps
around a tendon
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Frolich, Human Anatomy, Mechanics of Movement
Types of Synovial Joints
Types of Synovial Joints
The type of joint, in part, determines the range
and direction of movement
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The type of joint, in part, determines the range
and direction of movement
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HOW DOES MOVEMENT HAPPEN?
The elbow joint - a hinge joint allowing movement in 1 plane
HOW DOES MOVEMENT HAPPEN?
The elbow joint how the bicep and triceps control movement
Upper arm
bone humerus
The Capsule. Holds the bones of the
joint in place.
The synovial membrane.
Secretes synovial fluid
Capsule (ligaments)
Synovial membrane
Cartilage
Cartilage
Synovial
fluid
tendon
Triceps
muscle
humerus
biceps (flexor
When the triceps contracts
muscle), contracts
the elbow joint extends (its
joint angle increases).
Triceps
(extensor)
The biceps and triceps are
relaxes
called antagonistic muscles
because they have the
radius
opposite effect on the same
ulna
joint.
The synovial fluid. Lubricates the
movement of the cartilage surfaces
against each other – reducing
friction and preventing arthritis
(inflammation and joint damage).
Cartilage. Lubricates the movement of
the cartilage surfaces against each
other – reducing friction and preventing
arthritis (inflammation and joint
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damage).
When the biceps contracts
the elbow joint flexes (its joint
angle decreases).
THE BICEPS AND TRICEPS ARE
AN ANTAGONISTIC PAIR
Remember that for this to
work properly the biceps must
relax when the triceps
contracts, and vice versa.
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Clinical Forms of Arthritis
Inflammatory Conditions
Associated with Joints
Osteoarthritis
Most common chronic arthritis
Bursitis – inflammation of a bursa usually
caused by a blow or friction
Probably related to normal aging processes
Tendonitis – inflammation of tendon sheaths
Arthritis – inflammatory or degenerative
diseases of joints
Rheumatoid arthritis
An autoimmune disease – the immune system
attacks the joints
Over 100 different types
Symptoms begin with bilateral inflammation of
certain joints
The most widespread crippling disease in the
United States
Often leads to deformities
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Frolich, Human Anatomy, Mechanics of Movement
X-ray of hand affected by
arthritis
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Osteoarthritis
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Frolich, Human Anatomy, Mechanics of Movement
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Artificial Hip Joint
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Frolich, Human Anatomy, Mechanics of Movement
Gout
Lots of problems
with joints result
from sports
injuries
Click on the picture for the
web sports injury clinic
What can go wrong with joints
Dislocation The bones move
out of position, causing pain and
preventing joint movement
Tendons strain or tear
Making movement of the joint
painful and difficult
Cartilage damage
Movement becomes painful
or impossible and the joint
becomes inflamed.
Antagonistic muscle
damage due to too
overloading Making
Frolich, Human Anatomy, Mechanics of Movement
movement of the joint
painful and difficult
• Gout was historically known as "the disease of
kings" orby"rich
man's
• Caused
elevated
Characterized
by disease".
levels of uric
acid in of
recurrent
attacks
the
blood
which
acute
inflammatory
crystallize and are
arthritis.
deposited in joints,
• Metatarsal-phalangeal
tendons, and
joint
at the base
of the
surrounding
tissues.
big toe is the most
commonly affected.
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Bunions
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Homeostatic Imbalances
• The
bump is partly due
A deformity
to the swollen bursal
characterized
by lateral
sac.
of the
great
• deviation
The larger part
of the
bump As
is athe
normal
part
of
toe.
great
toe
the head of first
turns
in
toward
the
metatarsal bone that
has tilted toe
sideways
to
second
the tissues
stick
out at its the
top. joint
surrounding
Rickets
•Disease of children due to a lack of vitamin D.
•Calcium is not deposited in bones.
•Bones become soft.
•Bowing of the bones, and other deformities occur.
may become swollen
and tender.
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Homeostatic Imbalances
Osteomalacia
•“Rickets” of adults.
•Due to a lack of vitamin D.
•Calcium is not deposited in the bones.
•Bones become brittle.
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Osteogenesis Imperfecta
(sometimes known as brittle bone disease)
Type V
in an
adult
genetic bone
disorder
• born with
defective
connective
tissue, or
without the
ability to
make it.
Type V
in a
child
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Osteoporosis
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Homeostatic Imbalances
Osteoporosis
•Bone reabsorption is greater than bone deposition.
•Due to any of the following:
•Lack of estrogen in women.
•Lack of exercise to stress the bones.
•Inadequate intake of calcium and phosphorus.
•Abnormalities of vitamin D metabolism.
•Loss of muscle mass.
•Increased Risk for Fracture
compression fractures of vertebrae
hip fractures
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Life-Span Changes
• decrease in height at about age 30
• calcium levels fall
• bones become brittle
• osteoclasts outnumber osteoblasts
• spongy bone weakens before compact bone
• bone loss rapid in menopausal women
• hip fractures common
• vertebral compression fractures common
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Factors Affecting Bone
Development, Growth and Repair
•
•
•
•
•
•
•
Deficiency of Vitamin A – retards bone development
Deficiency of Vitamin C – results in fragile bones
Deficiency of Vitamin D – rickets, osteomalacia
Insufficient Growth Hormone – dwarfism
Excessive Growth Hormone – gigantism, acromegaly
Insufficient Thyroid Hormone – delays bone growth
Sex Hormones – promote bone formation; stimulate
ossification of epiphyseal plates
• Physical Stress – stimulates bone growth
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Male:
•Heavier
•Skull size is larger than females.
•Bones are thicker
•The forehead is slightly sloping or
receding.
•The vault of the skull is more rounded.
•The overall length of the skull is longer
•The chin is bigger and projects more
forwards
•The zygomatic bones are also more
massive.
•Supraorbital
•margins ore
•rounded
•The male pelvis is more robust, narrower, and taller than the female
pelvis. The angle of the male pubic arch and the sacrum are narrower as
well.
•The female pelvis is more delicate, wider and not as high as the male
pelvis. The angle of the female pubic arch is wide and round. The female
sacrum is wider than the male's and the iliac bone is flatter. The pelvic
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basin of the female is more spacious and less funnel-shaped.
Female:
•Lighter
•Skull size is smaller compared to
males.
•Bones are Thinner
•The forehead is vertical.
•The vault is flattened.
•The skull is Rounded
•The facial bones are smoother B
•Both the mandible and the maxilla
are smaller.
•Supraorbital
margin is sharp
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