Chapter 7– Bone Tissue
7-1
Ch. 7 Study Guide
1. Critically read Chapter 7:
A. 7.1-7.2 (pp. 206-214) right before section 7.3 (Bone
Development)
B. 7.4 (Physiology of Osseous Tissue) section (pp. 220224) before section 7.5 (Bone Disorders)
C. Deeper Insight boxes 7.1, 7.2, & 7.4 (Osteoporosis)
2. Comprehend Terminology (those in bold in the
textbook) within the reading scope above
3. Study-- Figure questions, Think About It
questions, and Before You Go On (section-ending)
questions (within the reading scope above)
4. Do end-of-chapter questions—s
–
–
Testing Your Recall— 1, 3-4, 6-12, 15-20
True or False– 1, 2, 4-10
7-2
§ Quotable Quotes
The University of Nebraska says that
elderly people that drink beer or wine
at least four times a week have the
highest bone density.
They need it - they're the ones falling
down the most. – Jay Leno
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I-- 7.1. Introduction
7-4
§ Bone and Skeleton
• The study of bone– Osteology
– Osseous—pertaining to bone
– Osteon— structural unit of . . .
– Osteocyte—a mature bone cell
– Osteoporosis—a degenerative bone
disease; loss of bone mass due to . . .
• Functions of the skeletal system
– support, protection, movement, electrolyte
balances, acid-base balance and blood
formation
7-5
§ Bone (Osseous tissue)—
A connective tissue or an organ?
• A connective tissue (C.T.; osseous
tissue) with a matrix hardened by
minerals (mainly calcium phosphate)– a
process called ___________________.
• “Bone”—denotes as an organ; individual
bones consist of many tissues--osseous
tissue, marrow, blood, cartilage, nervous
tissue
7-6
§ Shapes of Bones-- 4 groups
• 1. Long bones –longer
than wide; levers acted
upon by muscles; Ex.
humerus
• 2. Short bones – nearly
equal in length and width;
Ex. carpal and tarsal bones
• 3. Flat bones – protect
soft organs and provide for
muscle attachment; Ex.
scapula
• 4. Irregular bones —the
vertebrae and some skull
bones
7-7
§ Structures of long bones (A)-1. Diaphysis —its shaft; function:
2. Epiphysis — heads at each end;
functions:
3. Articular cartilage – The joint surface
where one bone meets another is covered
with a layer of hyaline cartilage
Fig. 7.2
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2
4-6
1
7-10
3
7-9
§ Structures of long bones (B)-1. Epiphyseal plate (growth plate;
in children)— What is it?
2. Epiphyseal line (in adults)—
Fig. X and Y
7-10
In children
7-11
An adult bone
7-12
§ Flat Bone of the Cranium
1. Sandwich like arrangement-2. Middle layer is _________________
A. Trabeculae-- A lattice of slender
rods and spines;
3. Skull fracture may fracture the outer
layer of compact bone, but leave inner
layer of compact bone unharmed
Fig. 7.3
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7-14
Match the following bones to
these four bone shapes
A. Long bone
B. Short bone
C. Flat bone
D. Irregular bone
1. _____ Vertebrae, sphenoid, ethmoid
2. _____ The three bones in each of your
fingers and toes (phalanges), humerus
3. _____ Ribs, scapula, most skull bones,
sternum
4. _____ Kneecap (patella), calcaneus
7-15
II-- 7.2. Histology of
Osseous Tissue
7-16
§ 1--Four Types of Bone Cells (1)
1. Osteogenic cell
2. Osteoblast
3. Osteocyte
1. Osteogenic cells (Stem cells) in
endosteum, periosteum or central canals
give rise to new osteoblasts
2. Osteoblasts (called ____________) form
bone matrix
3. Osteocytes are former osteoblasts
trapped in the matrix they formed; shape?
Functions? (a) maintain bone density; (b)
blood conc. of . . . (c) strain sensors 7-17
§ 1--Four Types of Bone Cells (2)
4. Osteoclasts (bone-dissolving cells)
develop in bone marrow by fusion of 350 stem cells; appearance?
Location:
A. Reside in pits (called resorption bays)
that they ate into the bone
B. Bone remodeling– combined action of
...
Fig. 7.4b
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7-19
Check point question
1. Mature bone cells are known as
_______.
2. Bone-building cells are called
________,
3. __________ are bone-resorbing cells.
7-20
§ 2--Matrix of Osseous Tissue
• Dry weight = 2/3 inorganic; 1/3 organic matter
1. Inorganic matter—supports the weight
– 85% hydroxyapatite– this is calcium
phosphate salt
– 10% calcium carbonate; 5% other minerals
– Disease —Rickets; bone softening and
deformity (Fig. x) or osteomalacia in adults
2. Organic matter—gives flexibility
– Collagen; Protein-CHO complexes
– Disease – Brittle bone disease; a defect in
collagen deposition (Fig. x)
3. Combination 1 and 2 above provides for
strength and resilience
4. Read Deeper Insight 7.1 (Bone Contamination)7-21
Rickets
7-22
Also called-Osteogenesis
imperfecta (a
genetic
disorder)
7-23
§ 3--Compact Bone (Fig. 7.4)
A. Periosteum (C.T.) wraps around bones
B. Osteon, basic structural unit of compact
bone, includes:
– a central canal (vascular canal)– joined by
transverse passages called perforating
canals; what inside these canals?
– concentric lamellae, from lamella to lamella
are right- and left-handed helices of collagen
fibers
C. Not all of the matrix is organized into
osteons. Circumferential lamellae— run
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parallel to the bone surface
Next
Slide
7-25
§ 4--Spongy Bone
A. Sponge like appearance formed by
plates of bone called Trabeculae
– Space– filled with ______________
B. Trabeculae have few osteons or central
canals; Why?
– B/C no osteocyte is very far from blood of
bone marrow
C. Provides strength with little weight
– trabeculae (not randomly arranged) develop
along bone’s lines of stress (Fig. 7.5)
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§ 5--Bone Marrow
• Def.– soft tissue that occupies the marrow
cavity of a long bone, the spaces amid the
trabeculae of spongy bone, and the larger
central canals. Two kinds: (Fig. 7.6)
1. Red marrow-- looks like thick blood
– Consists of reticular fibers (cells), immature
blood cells, adipocytes
– Function? Hemopoietic– produce blood cells
2. Yellow marrow– from red bone marrow
– Contains fatty tissue
– No longer produces blood cells
7-28
Fig. 7.6-Distribution
of red and
yellow bone
marrow
Figure 7.7
Q. Where
would be the
most
accessible
places to draw
red bone
marrow from
an adult?
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Skip section 7.3
(Bone Development;
pp. 214-219)
III—7.4. Physiology of
Osseous Tissue
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7-31
§ 7.4A. Mineral deposition
1. Mineralization/calcification –
definition: crystallization process in which
calcium, phosphate, . . .
– What is deposited? Calcium, phosphate, .
– When? Fetal life . . .
– By what cells?
2. Ectopic ossification– include
arteriosclerosis and calculus (“little
stone”)
7-32
§ 7.4B. Mineral resorption
1. Mineral resorption – definition: The
process of dissolving bone
– By what bone cells?
– Mechanism of mineral resorption–
• Calcium receptor, hydrogen pumps, and chloride
ions channels present
• Hydrochloric acid dissolves the bone minerals and
acid phosphatase digests the collagen
– Application– orthodontic appliances (braces)
to reposition teeth
Fig. X & Y (osteoclasts), Z (braces)
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Next
Slide
7-34
Acid phosphatase
7-35
Orthodontic braces
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§ 7.4C. Calcium Homeostasis
1. Calcium is important– neuron action
potentials, muscle contraction, blood
clotting, exocytosis, 2nd messenger etc.
2. (Location) Where is calcium deposited to
& withdrawn from?
3. Calcium in the blood—ionized form (Ca+2)
or is bound to solutes (proteins etc.)
– Hypocalcemia– calcium deficiency
– Hypercalcemia– a blood calcium excess
– (see the next slide for details)
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IV-- 7.4D. Calcium homeostasis by
three hormones–
-- calcitriol
-- calcitonin
-- parathyroid hormone (PTH)
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§ 7.4D. Calcium and calcitriol
1. Calcitriol (the most active form of vitamin D)–
synthesis (see Fig. 7.14)
–
–
–
Keratinocytes-- 7-dehydrocholesterol to vitamin D3
The liver-- coverts vitamin D3 to calcidiol
The kidney-- converts calcidiol to calcitriol
2. Function of calcitriol—Raise blood
calcium; How?
–
–
–
(where?) _________________– calcium & phosphate
absorption
Bone resorption– calcium resorption
Kidneys– reabsorption of calcium
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§ 7.4D. Calcium and calcitonin
1. Calcitonin – synthesis
–
–
By ________ (clear cells) of thyroid gland
Calcitonin is secreted when blood calcium
concentration rises too high
2. Function of calcitonin— lowers blood
calcium; How? On bones:
–
–
–
Osteoclast inhibition– reduces osteoclast activity;
less calcium is liberated from bones
Osteoblast stimulation– results in calcium
deposition
Fig. 7.16a
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❷ Blood ca+2
returns to normal
❶
Blood ca+2 excess
secretion
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§ 7.4D. Calcium and PTH
1. Parathyroid hormone (PTH)– synthesis
–
–
By the ____________ glands, located at the posterior
surface of the thyroid gland
PTH is secreted when blood calcium concentration is low
2. Function of parathyroid hormone (PTH)—
raises blood calcium level; How? On bones
and kidneys
–
–
–
–
Osteoclast stimulation– promotes osteoclast activity;
more calcium is liberated from bones
Osteoblast inhibition– results in less calcium deposition
Kidneys– PTH promotes calcium reabsorption by the
kidneys; PTH also promotes calcitriol synthesis in
kidneys
7-43
Fig. 7.16b
❷ Blood ca+2
returns to normal
❶
Blood ca+2 too low
secretion
7-44
Skip section 7.5 (Bone disorder;
pp. 225-227)
V– 7.5 on Osteoporosis;
read p. 228 in the textbook
(Deeper Insight 7.4)
7-45
§ 7.5. Osteoporosis
1. Symptoms– bones lose mass, become
brittle etc.
2. Causes— aging, bone resorption
3. Results– fractures, kyphosis etc.
4. Diagnosis– X rays to measure bone density
5. Treatments– estrogen (is out of favor), bisphosphonates etc.
6. Prevention– between the ages of 25-40;
exercise and a good bone-building diet
– 4 Figures
– Watch a video when available (also on the
publisher’s website)
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Sponge bone in the body of vertebra in good
health (Left) and with osteoporosis (Right)
Figure 7.22a
Left
Right
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Lumbar vertebrae
severely damaged by
osteoporosis
7-49
Kyphosis (widow’s
hump)
7-50
Questions (muddiest
points)?
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