1. Co 6

2. Skull Clavicle Sternum Humerus Ribs Vertebral column Pelvis Radius
Fig. 6.1
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Skull
Clavicle
Sternum
Humerus
Ribs
Vertebral
column
Pelvis
Radius
Ulna
Femur
Tibia
Fibula

3. Fig. 6.4 Compact bone Spongy bone Spaces containing bone marrow and
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Compact
bone
Spongy
bone
Spaces containing
bone marrow and
blood vessels
Trabeculae
(a)
Osteoblast
Osteoclast
Osteocyte
Trabecula
Lamellae
Canaliculus
(b)

4. Fig. 6.2
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Articular cartilage
Epiphysis
Epiphyseal plates
in juveniles
Epiphyseal lines
in adults
Spongy bone
Compact bone
Medullary cavity (contains
red marrow in juveniles and
yellow marrow in adults)
Diaphysis
Diaphysis
Periosteum
Endosteum
Young bone
(a)
(b)
Adult bone
Osteons
(haversian systems)
Endosteum
Inner
layer
Periosteum
Outer
layer
Compact bone
Central canals
Spongy bone
with trabeculae
Connecting vessels
Medullary
cavity
(c)
Adult bone

5. Fig. 6.3 Osteon Lamellae on surface of bone Osteon Concentric rings
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Osteon
Lamellae on
surface of bone
Osteon
Concentric rings
of lamellae
Lamellae
between osteons
Central canal
Periosteum
Blood vessel within
the periosteum
Blood vessels
connecting to
a central canal
Blood vessels
within a central
(Haversian) canal
Canaliculi
LM 400x
Osteocytes in
lacunae
(a)
Canaliculi
(b)
Lacunae
Blood vessel
connecting to
a central canal
between osteons
a: ©Trent Stephens

6. Fig. 6.4 Compact bone Spongy bone Spaces containing bone marrow and
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Compact
bone
Spongy
bone
Spaces containing
bone marrow and
blood vessels
Trabeculae
(a)
Osteoblast
Osteoclast
Osteocyte
Trabecula
Lamellae
Canaliculus
(b)

7. b: ©Biophoto Associates/Science Source
Fig. 6.5
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Parietal
bone
Frontal bone
Ossification
center
Ossification
center
Superior part
of occipital
bone
Ethmoid bone
Nasal bone
Inferior part
of occipital bone
Maxilla
Zygomatic bone
Temporal bone
Mandible
Vertebrae
Styloid
process
Sphenoid bone
(a)
Fontanel
Intramembranous
bones forming
Cartilage
Endochondral
bones forming
(b)
b: ©Biophoto Associates/Science Source

8. Fig. 6.6 Uncalcified cartilage Epiphysis Perichondrium Perichondrium
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Uncalcified
cartilage
Epiphysis
Perichondrium
Perichondrium
Calcified cartilage
Periosteum
Diaphysis
Bone collar
Cartilage
Blood vessel
to periosteum
Epiphysis 1
A cartilage model, with the general shape of the
mature bone, is produced by chondrocytes. A
perichondrium surrounds most of the cartilage model. 2
The chondrocytes enlarge, and cartilage is calcified. A
bone collar is produced, and the perichondrium of the
diaphysis becomes the periosteum.
Cartilage
Perichondrium
Calcified cartilage
Cartilage
Spongy
bone
Periosteum
Secondary
ossification
center
Blood vessel
Bone collar
Primary
ossification
center
Space in
bone
Calcified
cartilage
Blood vessel
Trabecula
Spongy bone
Medullary cavity
Periosteum
Bone collar
Blood vessel
Medullary cavity 3
A primary ossification center forms as blood vessels
and osteoblasts invade the calcified cartilage. The
osteoblasts lay down bone matrix, forming trabeculae. 4
Secondary ossification centers form in the epiphyses
of long bones.

9. Fig. 6.2
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Articular cartilage
Epiphysis
Epiphyseal plates
in juveniles
Epiphyseal lines
in adults
Spongy bone
Compact bone
Medullary cavity (contains
red marrow in juveniles and
yellow marrow in adults)
Diaphysis
Diaphysis
Periosteum
Endosteum
Young bone
(a)
(b)
Adult bone
Osteons
(haversian systems)
Endosteum
Inner
layer
Periosteum
Outer
layer
Compact bone
Central canals
Spongy bone
with trabeculae
Connecting vessels
Medullary
cavity
(c)
Adult bone

10. Fig. 6.7
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Femur
Patella
Epiphysis
Epiphyseal
plate
Diaphysis
(a)
Length of bone
increases.
Epiphyseal side 1
New cartilage is
produced on
the epiphyseal side
of the plate as the
chondrocytes divide
and form stacks
of cells.
Thickness of
epiphyseal
plate remains
unchanged. 1 1
Chondrocytes
divide and enlarge.
Epiphyseal
plate 2 2
Chondrocytes
mature and
enlarge. 2
Bone is
added to
diaphysis. 3
Calcified cartilage
is replaced by bone. 3
Matrix is calcified,
and chondrocytes
die. 3
Bone of
diaphysis 4
The cartilage on
the diaphyseal side
of the plate is
replaced by bone. 4 4
LM 400x
(b)
(c)
Diaphyseal side
a: ©Ed Reschke/Photolibrary/Getty Images; c: ©Biophoto Associates/Science Source

11. Fig. 6.2
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Articular cartilage
Epiphysis
Epiphyseal plates
in juveniles
Epiphyseal lines
in adults
Spongy bone
Compact bone
Medullary cavity (contains
red marrow in juveniles and
yellow marrow in adults)
Diaphysis
Diaphysis
Periosteum
Endosteum
Young bone
(a)
(b)
Adult bone
Osteons
(haversian systems)
Endosteum
Inner
layer
Periosteum
Outer
layer
Compact bone
Central canals
Spongy bone
with trabeculae
Connecting vessels
Medullary
cavity
(c)
Adult bone

12. Fig. 6.9 Decreased blood Ca2+ Increased blood Ca2+ 1 5
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Decreased
blood Ca2+
Increased
blood Ca2+ 1 5
Posterior aspect
of thyroid gland
Parathyroid
glands 1
Decreased blood Ca2+ stimulates PTH
secretion from parathyroid glands.
Kidney
Thyroid gland 2
PTH stimulates osteoclasts to break down
bone and release Ca2+ into the blood. 3
In the kidneys, PTH increases Ca2+
reabsorption from the urine. PTH also
stimulates active vitamin D formation. 3
PTH
Calcitonin 4
Vitamin D promotes Ca2+ absorption from the
small intestine into the blood. 2 6
Stimulates
osteoclasts
Inhibits
osteoclasts 5
Increased blood Ca2+ stimulates calcitonin
secretion from the thyroid gland.
Vitamin D 6
Calcitonin inhibits osteoclasts, which allows for
enhanced osteoblast uptake of Ca2+ from the
blood to deposit into bone.
Bone
Osteoclasts
promote Ca2+
uptake from
bone.
Ca2+ 4
Osteoblasts promote
Ca2+ deposition in bone.
Small intestine
Ca2+
Blood

13. Fig. 6.8 Compact bone Medullary cavity Woven bone External callus:
Copyright © McGraw-Hill Education. Permission required for reproduction or display.
Compact
bone
Medullary
cavity
Woven
bone
External callus:
Periosteum
Woven bone
Dead
bone
Hematoma
Cartilage
Broken humerus
Internal callus:
Compact
bone at
break site
Dead
bone
Fibers and
cartilage
Woven bone
Hematoma formation
Callus formation
Callus ossification
Bone remodeling 1
Blood released from
damaged blood vessels
forms a hematoma. 2
The internal callus forms
between the ends of the
bones, and the external
callus forms a collar
around the break. 3
Woven, spongy bone
replaces the internal
and external calluses. 4
Compact bone replaces
woven bone, and part
of the internal callus is
removed, restoring the
medullary cavity.
Callus around broken
humerus (at arrow)
(a)
(b)
a: ©Andrew F. Russo

14. Osteoporosis Symptoms Page 145 MUSCULAR INTEGUMENTARY NERVOUS
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MUSCULAR
Muscle atrophy from reduced activity.
Increased chance of falling and
breaking a bone.
INTEGUMENTARY
Limited sun exposure lowers
vitamin D production, which
reduces Ca2+ absorption.
NERVOUS
Pain from injury may reduce
activity level and therefore
further injuries.
Osteoporosis
Symptoms
Pain and stiffness especially in spine
Easily broken bones
Loss of height Treatment
Dietary calcium and vitamin D
Exercise
Calcitonin
Alendronate
REPRODUCTIVE Decreased estrogen following
menopause contributes
to osteoporosis.
ENDOCRINE
Calcitonin is used to
treat osteoporosis.
CARDIOVASCULAR
If bone breakage has occurred,
increased blood flow to that site
removes debris. Blood carries
nutrients necessary for repair.
DIGESTIVE
Inadequate calcium and
vitamin D intake can cause insufficient
Ca2+ absorption in small intestine.
RESPIRATORY
Excessive smoking lowers estrogen
levels, which increases bone loss.
LYMPHATIC AND IMMUNE
Immune cells help prevent infection after
surgery, such as hip replacement.