SKELETAL SYSTEM
Functions of the Skeletal System
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Bones are made of OSSEOUS TISSUE
Support
Protection
Movement
Blood cell formation (bone marrow) - hematopoeisis
Storage of organic and inorganic materials (salt,
calcium, potassium, lipids….)
ORGANIZATION
• About 206
bones in the
adult body
• 2 Main
Divisions –
Axial &
Appendicular
Axial Skeleton
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Head, neck, trunk
Skull
Hyoid Bone
Vertebral Column
Thoracic Cage (ribs, 12 pairs)
Sternum
Hyoid Bone
The hyoid bone is unique because it is the only bone that is not attached
to any other bones.
Appendicular Skeleton
• Limbs & Bones that connect to the
o Pectoral Girdle (shoulders)
o Pelvic Girdle (hips)
BONE STRUCTURE - Long Bone
1.Epiphysis
2.Diaphysis
3.Articular Cartilage
4.Periosteum
Inside the Long Bone
Medullary Cavity –
hollow chamber filled
with bone marrow
Red Marrow (blood)
Yellow Marrow (fat)
Endosteum
– lining of the
medullary
Types of Bone Tissue
Compact (wall of the diaphysis)
Spongy (cancellous, epiphysis) - red marrow
Structure of a Long Bone
Figure 6.3a-c
Review the Structure of a
Long Bone
Matching quiz at
http://www.mhhe.com/biosci/a
p/holehaap/student/olc2/chap0
7matching01.html
Microscopic Structure
MATRIX - where the bone cells live
OSTEOCYTES - mature bone cells, enclosed in
tiny chambers called LACUNAE
OSTEOCYTES form rings (LAMELLAE) around a
HAVERSIAN CANAL which houses blood vessels
Osteocytes are linked by CANALICULI
Haversian Canals are linked by VOLKMAN's
CANALS
Compact Bone
BONE
COLORING!
Test Yourself
Find the...
Haversian Canal
Volkman's Canal
Lamellae
Spongy Bone
Compact Bone
BONE DEVELOPMENT & GROWTH
1.Intramembranous bones – flat, skull
2. Endochondral bones – all other
ALL BONES START AS HYALINE
CARTILAGE, areas graduallly turn to bone
PRIMARY OSSIFICATION CENTER (shaft)
SECONDARY OSSIFICATION CENTER (ends)
Bone Development & Growth
EPIPHYSEAL
DISK (growth plate) is a
band of cartilage between
the epiphysis and
diaphysis
These areas increase
bone length as the cells
ossify
Cartilage becomes
OSTEOBLASTS become
OSTEOCYTES
RESORPTION
OSTEOCLASTS - dissolve bone tissue to
release minerals, process is called
RESORPTION
Bone Growth
Bone Growth
Abnormal Bone Conditions
• BONE SPURS: abnormal growth.
Can occur on any bone (e.g. heel).
• OSTEOPOROSIS: Increased
activity of osteoclasts cause a break
down bone, and the subsequent
fewer minerals in the extracellular
matrix make it fragile. The spongy
bone especially becomes more
porous.
• Men get it as well as women.
What’s the best way to prevent
osteoporosis? Exercise! What does
exercise do? Makes bones bigger.
• The most common bone used for a
bone graft is the iliac bone of the
hip.
Rheumatoid arthritis is an autoimmune disease which
causes joint stiffness and bone deformity
Source: http://www.thetimes.co.uk/tto/public/article3233439.ece
SCOLIOSIS
SCOLIOSIS is a lateral curve in the spine
KYPHOSIS
KYPHOSIS is a hunchback curve
LORDOSIS
LORDOSIS is a swayback in the lower region.
ANKYLOSIS
ANKYLOSIS is severe arthritis in the spine and the vertebrae fuse.