The Skeletal SystemThe Skeletal System
Slide 5.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Parts of the skeletal system
• Bones (skeleton)
• Joints: hold bone together & mobility
• Cartilages:
• Ligaments & Tendons
• Divided into two divisions
• Axial skeleton
• Appendicular skeleton
Functions of BonesFunctions of Bones
Slide 5.2Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Support of the body
• Protection of soft organs
• Movement due to attached skeletal muscles
• Storage of minerals and fats
• Blood cell formation
Bones of the Human BodyBones of the Human Body
Slide 5.3Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• The skeleton has 206 bones
• Two basic types of bone tissue
•Compact bone
•Homogeneous
•Spongy bone
•Small needle-like pieces of bone
•Many open spaces
Figure 5.2b
Classification of BonesClassification of Bones
Slide 5.4aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Long bones
•Typically longer than wide
•Have a shaft with heads at both ends
•Contain mostly compact bone
• Examples: Femur, humerus
Classification of BonesClassification of Bones
Slide 5.4bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Short bones
•Generally cube-shape
•Contain mostly spongy bone
•Examples: Carpals, tarsals
Classification of Bones on the Basis Classification of Bones on the Basis of Shapeof Shape
Slide 5.4cCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.1
Classification of BonesClassification of Bones
Slide 5.5aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Flat bones
•Thin and flattened
•Usually curved
•Thin layers of compact bone around a layer of spongy bone
•Examples: Skull, ribs, sternum
Classification of BonesClassification of Bones
Slide 5.5bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Irregular bones
•Irregular shape
•Do not fit into other bone classification categories
•Example: Vertebrae and hip
Gross Anatomy of a Long BoneGross Anatomy of a Long Bone
Slide 5.6Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Diaphysis
•Shaft
•Composed of compact bone
• Epiphysis
•Ends of the bone
•Composed mostly of spongy bone
Figure 5.2a
Structures of a Long BoneStructures of a Long Bone
Slide 5.7Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Periosteum
• Outside covering of the diaphysis
• Fibrous connective tissue membrane
• Sharpey’s fibers
• Secure periosteum to underlying bone
• Arteries
• Supply bone cells with nutrients
Figure 5.2c
Structures of a Long BoneStructures of a Long Bone
Slide 5.8aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Articular cartilage
• Covers the external surface of the epiphyses
• Made of hyaline cartilage
• Decreases friction at joint surfaces Figure 5.2a
Structures of a Long BoneStructures of a Long Bone
Slide 5.8bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Medullary cavity
•Cavity of the shaft
•Contains yellow marrow (mostly fat) in adults
•Contains red marrow (for blood cell formation) in infants Figure 5.2a
Bone MarkingsBone Markings
Slide 5.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Sites of attachments for muscles, tendons, and ligaments
• Passages for nerves and blood vessels
• Categories of bone markings
•Projections and processes – grow out from the bone surface
•Depressions or cavities – indentations
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone
Slide 5.10aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone
Slide 5.10bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.3
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone
Slide 5.11aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Lacunae
•Cavities containing bone cells (osteocytes)
•Arranged in concentric rings
• Lamellae
•Rings around the central canal
•Sites of lacunaeFigure 5.3
Microscopic Anatomy of BoneMicroscopic Anatomy of Bone
Slide 5.11bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Canaliculi
•Tiny canals
•Radiate from the central canal to lacunae
•Form a transport system Figure 5.3
Changes in the Human SkeletonChanges in the Human Skeleton
Slide 5.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• In embryos, the skeleton is primarily hyaline cartilage
• During development, much of this cartilage is replaced by bone
• Cartilage remains in isolated areas
•Bridge of the nose
•Parts of ribs
•Joints
Bone GrowthBone Growth
Slide 5.13aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Bones are remodeled and lengthened until growth stops
• 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
Long Bone Formation and GrowthLong Bone Formation and Growth
Slide 5.14aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.4a
Long Bone Formation and GrowthLong Bone Formation and Growth
Slide 5.14bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.4b
Types of Bone CellsTypes of Bone Cells
Slide 5.15Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Osteocytes• Mature bone cells
• Osteoblasts• Bone-forming cells
• Osteoclasts• Bone-destroying cells
• Break down bone matrix for remodeling and release of calcium
• Bone remodeling is a process by both osteoblasts and osteoclasts
Bone FracturesBone Fractures
Slide 5.16Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• 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
Bone FractureTypes
Quiz on Types of Fractures
Repair of Bone FracturesRepair of Bone Fractures
Slide 5.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Hematoma (blood-filled swelling) is formed
• Break is splinted by fibrocartilage to form a callus. Osteoclasts break down bone.
• Fibrocartilage callus is replaced by a bony callus. Osteoblasts form bone and become Osteocytes .
• Bony callus is remodeled to form a permanent patch.
Stages in the Healing of a Bone Stages in the Healing of a Bone FractureFracture
Slide 5.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.5
Self-Care for Broken Bones
Check Out Dem Bones!
Facial Bones Quiz
Classification of Bones Quiz
Fetal Skull• Adult skull is 1/8 body length (infant
is ¼)
• When born, skeleton is unfinished –fontanels(soft spots)
• Largest are anterior and posterior
• Allow skull to compress in birth, room for brain to grow
Paranasal SinusesParanasal Sinuses
Slide 5.25bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Functions of paranasal sinuses
•Lighten the skull
•Give resonance and amplification to voice
Figure 5.10
Structural Classification of JointsStructural Classification of Joints
Slide 5.45Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Fibrous joints
•Generally immovable; bones connected by fibrous tissue: sutures
• Cartilaginous joints
• Immovable or slightly moveable; bones connected by cartilage: spine
• Synovial joints
•Freely moveable; have joint cavity with synovial fluid: elbow, wrist
Functional Classifications of Joints
• Synarthrosis
-immovable joint
• Amphiarthrosis
-a slightly movable joint
• Diarthrosis
-a freely movable joint
Let’s see the joints move.
• Don’t click on the cowboy, just hit next.
Moving Joints
Different Joint StructuresDifferent Joint Structures
Slide 5.46Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.27d, e
Structures Associated with the Structures Associated with the Synovial JointSynovial Joint
Slide 5.50Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Bursae – flattened fibrous sacs
• Lined with synovial membranes
• Filled with synovial fluid
• Not actually part of the joint
The Synovial JointThe Synovial Joint
Slide 5.51Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.28
Slide 5.52aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.29a–c
Types of Synovial Joints Based on Types of Synovial Joints Based on ShapeShape
Slide 5.52b
Copyright ©2003 Pearson Education, Inc. publishing as Bejamin Cummings
Figure 5.29d–f
Types of Synovial Joints Based on Types of Synovial Joints Based on ShapeShape
Types of Joints Quiz
Inflammatory Conditions Associated Inflammatory Conditions Associated with Jointswith Joints
Slide 5.53Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Bursitis – inflammation of a bursa usually caused by a blow or friction
• Tendonitis – inflammation of tendon sheaths
• Arthritis – inflammatory or degenerative diseases of joints
•Over 100 different types
•The most widespread crippling disease in the United States
Clinical Forms of ArthritisClinical Forms of Arthritis
Slide 5.54aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Osteoarthritis
• Most common chronic arthritis
• Probably related to normal aging processes
• Rheumatoid arthritis
• An autoimmune disease – the immune system attacks the joints
• Symptoms begin with bilateral inflammation of certain joints
• Often leads to deformities
Two types of arthritis explained.
• Click on both boxes
Rheumatoid Arthritis Osteoarthritis
Gouty Arthritis (gout)• Uric acid accumulates in blood and
deposited in soft tissues of joints –painful attack of single joint (big toe)
• Males after 30, genetic
• Treatment – drugs, weight management
Developmental Aspects• Fetal development – flat and long
bones are converted to bone
• Birth – fontanels still remain for brain growth up to 2 years
• Adolescence – epiphyseal plates of long bones are ossified (quit growing)
Developmental Aspects• Puberty – female pelvis broadens
for childbearing, male skeleton becomes more robust
• Osteoporosis– loss of bone mass leading to thin, fragile bones
• In women – menopause estrogen deficiency, diet poor in Ca, smoking, or inactivity
Osteoporosis
Normal Osteoporosis
Herniated Disc
• Pressure on a disc ruptures the outer layer and forces the soft center (nucleus pulposus) out, which then puts pressure on a spinal nerve
• Most occur in lumbar region
Abnormalities of Spine• Scoliosis – abnormal lateral
curvature, can result in having one leg longer than the other
• Kyphosis (hunchback) – exaggerated thoracic curve
• Lordosis (swayback) – exaggerated lumbar curve
Scoliosis Kyphosis Lordosis