The Skeletal System
Chapter 5
1
Objectives:
•List and describe the major functions of the skeletal
system.
•Describe the types of various bone tissues, their
locations, and functions.
•List, describe and give specific examples of the
types of bones.
•List and describe the two major divisions of the
skeletal system and the bones which compose each.
•Describe the process of bone formation.
•List and describe the various types of joints.
•List and describe various disorders and diseases of
the skeletal system.
2
The Skeletal System
What would you look like if you did
not have any bones? Take a minute
a make a sketch of what you think
you might look like. Could you
stand up? Could you walk?
Without bones you would be just a
puddle of skin and organs on the
floor.
Click on the trunk's lid and then use the red knob to
pull the object from the trunk.
The human
skeleton contains
206 bones!
Functions of the Skeletal
System
•Support of the body
•Protection of soft organs
•Movement due to attached skeletal
muscles
•Storage of minerals and fats
•Blood cell formation (hematopoiesis)
3
Types of Bone Tissue
Diagram on p. 118
The skeleton has 206 bones
Two basic types of bone tissue
Compact bone
Homogeneous
Located on the outside
surface
Spongy bone
Small needle-like
pieces of bone (trabeculae)
Many open spaces
Where marrow is located
4
Compact Bone Spongy Bone
- hard bone
- surrounds spongy bone
- made of osteon systems
that contain blood vessels
- made of osteocytes
(living bone cells)
- less dense bone
- contains many holes
and spaces
spongy
compact
Classification of Bones by Shape
•Long bones
–Typically longer than wide
–Have a shaft (long, central cylinder) with
heads at both ends
–Contain mostly compact bone
•Examples: Femur, humerus
•Short bones
–Generally cube-shape
–Contain mostly spongy bone
•Examples: Carpals, tarsals
5
Classification of Bones by
Shape
•Flat bones
–Thin and flattened
–Usually curved
–Thin layers of compact bone around a layer of
spongy bone
•Examples: Skull, ribs, sternum
•Irregular bones
–Irregular shape
–Usually with projections (processes) or openings
(foramen)
–Do not fit into other bone classification categories
•Example: Vertebrae and pelvic bones
6
Classification of Bones by Shape
Diagram on p. 117
7
Color in the types of bones
based on the correct
classifications.
Microscopic Bone Anatomy
8
Microscopic Bone Anatomy
•Osteon (Haversian
System)
–A unit of bone
•Central (Haversian) canal
–Opening in the center of an
osteon
–Carries blood vessels and
nerves
•Perforating (Volkman’s)
canal
–Canal perpendicular to the
central canal
–Carries blood vessels and
nerves
Diagram on p. 120
9
Microscopic Bone Anatomy
•Lacunae
–Cavities containing bone cells
(osteocytes)
–Arranged in concentric rings
•Lamellae
–Rings around the central
canal
–Sites of lacunae
•Canaliculi
–Tiny canals
–Radiate from the central canal
to lacunae
–Form a transport system
between cells
Diagram on p. 120
10
Bone Cell Types
•Osteocytes
–Mature bone cells surrounded by matrix
•Osteoblasts
–Bone-forming cells produce new matrix
•Osteoclasts
–Bone-destroying cells
–Break down bone matrix for remodeling and release of
calcium
•Bone remodeling is a process by both
osteoblasts and osteoclasts.
–During your life span the your skeleton is broken down
and rebuilt completely on the average of seven times!
11
Canaliculi
Sharpey's fibers
Lacunae
Osteocytes
Periosteum
Lamella
Volkmann's canal
Lamella
Blood vessel
Haversian/central canal
Osteon
Compact bone
Spongy bone
Review! Bone Classifications
Long Bones
Flat Bones
Irregular Bones
Short Bones
Gross Anatomy of a Long Bone
•Diaphysis
Diagram on p. 118
–Shaft
–Composed of compact bone
•Epiphysis
–Ends of the bone
–Composed mostly of spongy bone
–Contains red marrow
•Medullary cavity
–Cavity of the shaft
–Contains yellow marrow (mostly fat) in
adults
•Articular cartilage
–Covers the external surface of the epiphyses
–Made of hyaline cartilage
–Decreases friction at joint surfaces
13
Gross Anatomy of a Long Bone
•Periosteum
Diagram on p. 118
–Outside covering of the
diaphysis
–Fibrous connective tissue
membrane
•Sharpey’s fibers
–Secure periosteum to underlying
bone
•Endosteum
- Inner lining of the
medullary cavity
•Arteries, veins, nerves
–Found in the Haversian and
Volkman canal systems within
the compact bone.
14
Bone Development and Growth
•During development,
cartilage is replaced by
bone (ossification)
•Cartilage remains in
isolated areas
Diagram on p. 121
–Bridge of the nose
–Parts of ribs
–Joints
•Bones are remodeled
and lengthened until
growth stops
–Bones change shape
somewhat
–Bones grow in width
15
Bone Development and Growth
•Epiphyseal plates allow
for growth of long bone
during childhood
–New cartilage is
continuously formed
–Older cartilage becomes
ossified
•Cartilage is broken down
•Bone replaces cartilage
16
Periosteum
Medullary Cavity
Cartilage
Compact bone
Epiphysis Periosteum
Epiphysis
Blood vessels
Spongy bone
Compact bone
Epiphyseal line
Cartilage
Bone marrow Compact bone Diaphysis
Sharpey's fibers
Spongy bone
Divisions of the Skeleton
•The Skeleton is divided into two major
regions:
a. Axial Skeleton
b. Appendicular Skeleton
•Axial Skeleton - longitudinal part of the
body
–Divided into three parts
•Skull
•Vertebral column
•Bony thorax
19
Divisions of the Skeleton
•Appendicular skeleton - appendages and
joints
–Limbs (appendages)
–Pectoral girdle (shoulder, scapula, and clavicle)
–Pelvic girdle (pelvis)
20
Divisions of the Skeleton
Diagram p.
125
21
22
Label Mr. Bones!
Tibia
Cranium
Radius
Sternum
Sacrum
Metacarpals
Patella
Fibula
Humerus
Ulna
Clavicle
Mandible
Scapula
Ribs
Pelvic
Metatarsals
Vertebra
patella
humerus
femur
scapula
radius
vertebra
metatarsals
skull
clavicle
ulna
tibia
fibula
pelvis
metacarpals
costals
Boneyard Bill's
Body Parts
Can you drag all the bones to their correct locations?
As you find
the bones,
identify them
on Steve!
BONES, BONES, BONES
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How fast can your class find the words?
TIBIA
CLAVICLE PELVIS
CRANIUM PHALANGES ULNA
FEMUR
RADIUS
VERTEBRA
FIBULA
RIBS
SCAPULA
HUMERUS JAWBONE
STERNUM
SPINE
PATELLA
Axial Skeleton: The Skull
•Two sets of bones
–Cranium
–Facial bones
•Bones are joined by sutures (fixed,
non-movable joints)
•Only the mandible is attached by a freely
movable joint
23
Axial Skeleton: The Skull
Diagram p. 126
24
Diagram p.
129
Axial Skeleton: The Skull
25
Diagram p.
127
Axial Skeleton: The Skull
26
Axial Skeleton: The Skull
•Paranasal sinuses: Hollow portions of bones
surrounding the nasal cavity
–Functions
•Lighten the skull
•Give resonance and amplification to voice
Diagram p.
128
27
Auditory meatus
Mental foramen
Frontal bone
Mandibular ramus
Nasal bone
Mastoid process
Suture
Parietal bone
Ethmoid bone
Temporal bone
Suture
Lacrimal bone
Occipital bone
Mandible
Maxilla
Suture
Sphenoid bone
Zygomatic bone
Styloid process
Practice Makes Perfect!
Parietal bone
Temporal bone
Nasal bone
Optic canal
Middle nasal concha
Mandible
Alveolar margins
Suture
Vomer
Zygomatic bone
Inferior nasal concha
Ethmoid bone
Lacrimal bone
Sphenoid bone
Maxilla
Frontal bone
Axial Skeleton: Hyoid Bone
Diagram p.
130
The only bone
that does not
articulate with
another bone
Serves as a
moveable base for
the tongue
Figure 5.12
30
Axial Skeleton: Vertebral Column
Vertebrae are
separated by
intervertebral discs
composed of
fibrocartilage
The spine has a
normal curvature
Each vertebrae is
given a name
according to its
location
Diagram p. 131
31
Axial Skeleton: Vertebral
Column
32
Diagram p. 133
Thoracic vertebrae
Cervical vertebrae
Coccyx
C1 Atlas
Lumbar vertebrae
C2 Axis
Sacrum
Appendicular Skeleton: Pectoral
Girdle
•Composed of two bones
–Clavicle – collarbone
–Scapula – shoulder blade
•These bones allow the upper limb to have
exceptionally free movement
36
Appendicular Skeleton: Pectoral
Girdle (Shoulder)
37
Diagram p. 139
Appendicular Skeleton: Brachium
Region
The arm is
formed by a
single bone
Humerus
Diagram p. 140
38
Appendicular Skeleton:
Antebrachium Region
•The forearm has
two bones
•Ulna (side adjacent
to little finger)
•Radius (side
adjacent to thumb)
39
Diagram p. 140
Appendicular Skeleton: Carpus,
Manus, and Digits Region
The hand
Carpals – wrist
Metacarpals – palm
Phalanges – fingers
Diagram p. 141
40
Appendicular Skeleton: Pelvic
Girdle
•Hip bones
•Composed of three pair of fused bones
–Ilium
–Ischium
–Pubic bone
•The total weight of the upper body rests on the
pelvis
•Protects several organs
–Reproductive organs
–Urinary bladder
–Part of the large intestine
41
Appendicular Skeleton: Pelvic
Girdle
The sacrum and coccyx are part of the
axial skeleton not appendicular skeleton.
42
Diagram p. 142
Appendicular Skeleton: Pelvic Girdle
Coxal Bone Structure
43
Diagram p. 142
Appendicular Skeleton: Pelvic Girdle
Male and Female Pelvis Comparison
Diagram p. 142
44
Appendicular Skeleton: Femoral
Region
The thigh has
one bone
Femur – thigh
bone
45
Diagram p. 144
Appendicular Skeleton: Patellar and
Crural Regions
The leg has
two bones
Tibia
Fibula
46
Diagram p. 144
Appendicular Skeleton: Tarsal, Pes,
and Digits Regions
The foot
Tarsus – ankle
Metatarsals –
sole
Phalanges – toes
47
Diagram p. 145
Word Sort! Arrange the words into categories!
Occipital bone
Scapula
Sternum
Suture
Lacunae
Temporal bone
Spongy
Zygomatic bone
Femur
Sphenoid bone
Osteoblast
Carpals
Cartilage
Lumbar
Vertebra
Lamella
Humerus
Marrow
Frontal bone
Central canal
Pelvis
Nasal bone
Cranium
Mandible
Maxilla
Ethmoid bone
Diaphysis
Phalanges
Patella
Costals
Ossification
Osteoclast
Cervical
Epiphysis
Volkmann's canal
Parietal bone
Compact
Articulations: Joints
•A joint is a location where two or more bones
meet.
•Functions of joints
–Hold bones together
–Allow for mobility
49
Types of Joints
•Ways joints are classified functionally:
•Synarthroses – immovable
•Amphiarthroses – slightly moveable
•Diarthroses – freely moveable
•Ways joints are classified structurally:
–Fibrous joints
•Generally immovable (sutures of skull)
–Cartilaginous joints
•Immovable or slightly moveable (vertebral disc)
–Synovial joints
•Freely moveable (shoulder, pelvis, knee, elbow, digits)
•Articulating bones are separated by a joint cavity
•Synovial fluid is found in the joint cavity
50
Anatomy of Synovial Joints
•Articular cartilage – (hyaline) covers ends
of bones
•Fibrous articular capsule – enclose joint
surfaces; lined with synovial membrane
•Joint cavity – cavity between bones of a
joint containing a lubricating fluid called
synovial fluid
•Ligaments – reinforce the joint
51
Structure of a Synovial Joint
Figure 5.28
52
Diagram p. 149
Type of Synovial Joints
53
Diagram p. 151
Types of Synovial Joints
54
Diagram p. 151
Gliding
Pivot
Hinge
Ball and Socket
Identify the type of joint in the diagrams.
What joint(s) is she using?
Gliding
Ball and Socket
Hinge & Pivot
Diseases and Disorders of the
Skeletal System
•A fracture is a break in a bone
•Types of bone fractures
–Closed (simple) fracture – break that does not
penetrate the skin
–Open (compound) fracture – broken bone
penetrates through the skin
•Bone fractures are treated by reduction and
immobilization
–Realignment of the bone
55
Diseases and Disorders of the
Skeletal System
•Open reduction – surgery is needed to
secure the bones together with pins or
wires.
•Closed reduction – bone ends coaxed
back into position by physician
56
Diseases and Disorders of the
Diagram p. 123
Skeletal System
57
Diseases and Disorders of the
Skeletal System: Fractures
Identify the fractures.
Simple
Greenstick
radius
Simple
Spiral
fibula
Compound
Fracture
tibia and
fibula
X - Ray
Comminuted
Fracture
radius
58
NQ
Diseases and Disorders of the
Skeletal System
•Osteoporosis: afflicts
both men and women
but most common in
post menopausal
women
–Bone tissue becomes
brittle and breaks easily
with little applied stress
–Cause - loss of calcium
from bone matrix
59