Chapter 5
The Skeletal System
Cecie Starr | Beverly McMillan
The Skeletal System
Key Concepts
•
•
•
•
The Structure and Functions of Bones
The Skeleton
Joints
Disorders of the Skeleton
5
The Skeletal System
5
• Joint problems due to:
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–
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Disease
Sports injuries
Obesity
Aging
Osteoarthritis
• Traditional vs.
nontraditional remedies
for arthritis
p87
5.1 Bone: Mineralized Connective Tissue
The Structure and Functions of Bones
• Bones are composed of connective tissue
hardened by the mineral calcium
5.1 Bone: Mineralized Connective Tissue
• Bones
– Living cells and matrix
– Periosteum
• Osteoblasts
– Secretion of collagen and
elastin and other substances
• Osteocytes
Figure 5-1 p88
5.1 Bone: Mineralized Connective Tissue
space occupied
by living bone cell
compact
bone tissue
spongy
bone
tissue
blood
vessel
osteon
(Haversian
system)
Figure 5-1a p88
5.1 Bone: Mineralized Connective Tissue
spongy
bone tissue
compact bone
tissue
Figure 5-1b p88
blood vessel
outer layer
of dense
connective tissue
5.1 Bone: Mineralized Connective Tissue
There are two types of bone tissue.
• Compact bone
– Dense tissue
– Osteon (Haversian system)
• Spongy bone
– Inside long bone’s shaft
– Looks lacy; quite strong
• How do nutrients get to
bone tissue?
Figure 5-1 p88
5.1 Bone: Mineralized Connective Tissue
A bone develops on a cartilage model.
• Early human embryo
– Cartilage and membranes
Forming
bone collar
Cartilage model
of future bone in
embryo
• Bone-forming osteoblasts
form around cartilage
shaft
• Calcification, blood
vessels, and nerves
infiltrate the bone tissue
• Epiphysis
Mature bone
of adult
– Epiphyseal plate of
cartilage
epiphyses
Figure 5-2 p89
Forming
bone collar
Cartilage model of
future bone in embryo
When organs form in
embryo, blood vessel
invades model;
osteoblasts start
producing bone tissue;
marrow cavity forms
Remodeling and
growth continue in
newborn; secondary
bone-forming centers
appear at knobby
ends of bone
Mature bone of adult
epiphyses
Stepped Art
Figure 5-2 p89
5.1 Bone: Mineralized Connective Tissue
Bone tissue is constantly “remodeled.”
• Osteoclasts and bone remodeling
• Important functions
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–
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Keeps bones resilient
Mechanical stress
Repair of broken bones
During growth
Homeostasis of blood calcium levels
• Osteoporosis- causes and treatments
5.2 The Skeletal System: The Body’s Bony Framework
The Skeleton
• Bones provide a hard surface against which muscles
can exert force to move body parts
5.2 The Skeletal System: The Body’s Bony Framework
• Vary in size and shape
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–
–
–
Long and slender
Short
Flat
“Irregular”
• Complex tissue: associated with joints, blood
vessels, and nerves
• Bone marrow
– Formation of blood cells
– Role of long bones, flat bones, and irregular bones
5.2 The Skeletal System: The Body’s Bony Framework
The skeletal system consists of bones, ligaments, and
tendons.
• Organization of human’s 206 bones
– Axial skeleton
– Appendicular skeleton
• Ligaments
– Connect bones to joints
• Tendons
– Attach muscles to bones or other muscles
nutrient canal into and from
marrow (for blood vessels and
nerves)
marrow cavity
compact bone tissue
spongy bone tissue
Figure 5-3 p90
Table 5-1 p90
A Skull bones
Cranial bones
Facial bones
B Rib cage
Sternum (breastbone)
Ribs (twelve pairs)
C Vertebral column, or
backbone
Vertebrae
(twenty-six bones)
Intervertebral disks
Axial Skeleton
Appendicular Skeleton
5.2 The Skeletal System
D Pectoral girdle and upper
limb bones
Clavicle (collarbone)
SCAPULA (shoulder blade)
HUMERUS (upper arm bone)
RADIUS (forearm bone) ULNA
(forearm bone)
CARPALS (wrist bones)
1
2
3
4
5
Metacarpals (palm bones) Phalanges
(thumb, finger bones)
E Pelvic girdle and lower
limb bones
Pelvic girdle (six fused bones)
Femur (thighbone)
Patella (kneebone)
ligament
(to knee cap)
Tibia (lower leg bone)
Fibula (lower leg bone)
Tarsals (ankle bones)
Metatarsals (sole bones)
Phalanges (toe bones)
Figure 5-4 p91
5.2 The Skeletal System: The Body’s Bony Framework
Bones have several important functions.
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•
•
•
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Movement
Support and anchor skeletal muscles
Enclose and protect organs
Store calcium and phosphorus
Blood cell formation
Take home message
What are the parts of the skeletal system?
5.3 The Axial Skeleton
• The axial skeleton supports much of our body weight
and protects many internal organs
5.3 The Axial Skeleton
The skull protects the brain.
• Brain case with sinuses
• Frontal bone
• Temporal bones
• Sphenoid bone
5.3 The Axial Skeleton
parietal bone
frontal
bone
sphenoid bone
ethmoid bone
temporal
bone
lacrimal bone
zygomatic bone
maxilla
occipital bone
external auditory meatus
(opening of the ear; part
of the temporal bone)
mandible
Figure 5-5a p92
5.3 The Axial Skeleton
frontal sinus
sphenoid sinus
ethmoid sinus
maxillary sinus
Figure 5-5c p93
5.3 The Axial Skeleton
The skull protects the brain.
• Parietal bones
• Occipital bone
• Foramen magnum
• Ethmoid bone
5.3 The Axial Skeleton
hard
palate
maxilla
maxilla
palatine
bone
vomer
zygomatic bone
sphenoid
bone
jugular
foramen
temporal bone
foramen
magnum
parietal bone
occipital bone
Figure 5-5b p92
5.3 The Axial Skeleton
Facial bones support and shape the face.
• Mandible
• Maxillary bones
• Zygomatic bones
• Lacrimal bone
• Palatine bones
• Vomer bone
Figure 5-5a p92
5.3 The Axial Skeleton
The vertebral column is the backbone.
• Flexible backbone
• Protects spinal cord
• Thirty-three vertebrae
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Cervical
Thoracic
Lumbar
Sacral
Coccyx
• Intervertebral disks: absorb shocks
– Composition
– Herniated disk
5.3 The Axial Skeleton
cervical
vertebrae
(7)
thoracic
vertebrae
(12)
lumbar
vertebrae
(5)
intervertebral
disks
sacrum
(5 fused)
coccyx
(4 fused)
Figure 5-6 p93
5.3 The Axial Skeleton
The ribs and sternum support and help protect internal
organs.
• Ribs
– Attached to vertebral column
– Protection of several organs
– Role in breathing
• Sternum
– Attached to upper ribs
Take home message
What are the parts of the axial skeleton?
5.4 The Appendicular Skeleton
• The appendicular skeleton includes the bones that
support the limbs, upper chest, shoulders, and
pelvis
5.4 The Appendicular Skeleton
The pectoral girdle and upper
limbs provide flexibility.
clavicle
• Pectoral girdle
humerus
• Scapula
sternum
scapula
• Clavicle
ulna
radius
carpals (8)
metacarpals (5)
phalanges (14)
Figure 5-7 p94
5.4 The Appendicular Skeleton
• Arm and hand bones
– Humerus
– Radius and ulna
– Carpals; carpal tunnel
syndrome
– Metacarpals
– Phalanges
clavicle
humerus
sternum
scapula
• Pectoral girdle
• Scapula
ulna
radius
• Clavicle
carpals (8)
metacarpals (5)
phalanges (14)
Figure 5-7 p94
5.4 The Appendicular Skeleton
pelvis
sacrum
• Pelvic girdle
– Coxal bones
– Pubic arch
– Differences between
males and females
pubic
symphysis
femur
• Leg and foot bones
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Femur
Tibia and fibula
Tarsals
Metatarsals
Take home message
patella
tibia
fibula
metatarsals
phalanges
What are the parts of the
appendicular skeleton?
tarsals
Figure 5-8 p95
5.5 Joints: Connections between Bones
Joints
• Joints are areas of contact or near contact
between bones
• All joints have some form of connective tissue that
bridges the gap between bones
5.5 Joints: Connections between Bones
• Synovial joint
– Synovial fluid
– Movement
• Cartilaginous joint
– Slight movement
• Fibrous joint
– No cavity
– Generally no movement
5.5 Joints: Connections
between Bones
fibrous joint attaches
tooth to jawbone
synovial joint (ball
and socket) between
humerus and scapula
cartilaginous joint
between rib and sternum
cartilaginous joint
between adjacent
vertebrae
synovial joint (hinge
type) between
humerus and radius
synovial joint (ball
and socket) between
pelvic girdle and
femur
Figure 5-9a p96
5.5 Joints: Connections between Bones
femur
patella
cartilage
ligaments
menisci
tibia
fibula
Figure 5-9b p96
5.5 Joints: Connections between Bones
A flexion and extension
flexion at
shoulder
hyperextension
extension
at shoulder
flexion at knee
extension at knee
Figure 5-10a p97
5.5 Joints: Connections between Bones
abduction
circumduction
adduction
abduction
abduction
adduction
rotation
adduction
B circumduction and rotation
C abduction and adduction
Figure 5-10bc p97
5.5 Joints: Connections between Bones
D supination and pronation
supination
pronation
Figure 5-10d p97
5.5 Joints: Connections between Bones
Take home message
What is a joint?
E
gliding movement
between carpals
Figure 5-10e p97
5.6 Disorders of the Skeleton
Disorders of the Skeleton
• Tissue in bones or
• Inflammation is the culprit
joints may break down
in repetitive motion injuries
– Osteoarthritis
– Rheumatoid arthritis
– Tendinitis
– Carpal tunnel syndrome
5.6 Disorders of the Skeleton
Joints are susceptible to strains, sprains, and dislocations.
• Causes and treatments of some joint injuries
– Strain
– Sprain
– Dislocation
Figure 5-11 p98
5.6 Disorders of the Skeleton
Bones break in various ways.
• Types of bone fractures
– Simple
– Complete
– Compound
• Treatment
• Effect of aging and
smoking on healing
A Simple
B Complete
C Compound
Figure 5-13 p99
5.6 Disorders of the Skeleton
Genetic diseases, infections, and
cancer all may affect the skeleton.
• Causes and treatments
of some skeletal
disorders
– Osteogenesis
imperfecta (OI)
– Bone and bone marrow
infections
– Osteosarcoma
Figure 5-14 p99
5.7 The Skeletal System in Homeostasis
The Skeletal System
The skeleton supports and helps
protect soft body parts. Bones,
joints, tendons, and ligaments all
have essential roles in moving the
body and its parts. Bone is a
reservoir for calcium, which is vital
for many body functions including
muscle contractions, the
transmission of nerve impulses,
and blood clotting. Calcium also is
required for the proper functioning
of some enzymes and of proteins in
the cell plasma membrane.
p100
Integumentary system
The skeleton provides support
for skin and the muscles below it.
Muscular system
Skeletal muscles attach to
bones, which serve as levers for
body movements. Bone calcium
may be released as needed to
maintain blood levels required for
muscle contractions.
p100
Digestive system
Bone stores dietary calcium and phosphorus.
Bones of the rib cage and pelvis protect
organs including the stomach, liver, and
intestines. Facial bones have sockets for teeth.
Cardiovascular system and blood
Bone calcium is available for heart
contractions that pump blood. All types of
blood cells form in red bone marrow.
Immunity and the lymphatic system
White blood cells that function in body
defenses form in bone marrow.
p100
Respiratory system
The rib cage and sternum protect the lungs.
Muscles used in breathing attach to ribs and
associated cartilages.
Urinary system
The rib cage partially protects the kidneys.
The pelvis helps protect the bladder.
Nervous system
The skull protects the brain. Vertebrae protect
the spinal cord. Bone calcium stores may be
released as needed to maintain blood levels
required for transmission of nerve impulses.
p100
Sensory systems
Skull and facial bones surround and protect
sensory organs in the head. Calcium in
bones helps maintain blood levels required for
transmission of sensory nerve impulses.
Endocrine system
Calcium may be released as needed
to maintain blood levels required for the
formation and secretion of many hormones.
Reproductive system
Pelvic bones protect female reproductive
organs and associated glands in males.
Calcium is available to help nourish a fetus
and for milk production in a nursing mother.
p100
Table 5-2 p101