Unit 2: The Skeletal System
Lab 4: Bone Tissues and Articulation
Jessica Radke-Snead, MS, RD
Bio 241 Anatomy and Physiology
Review
• See assignment for Lecture 1 (faculty website)
for review of labs 1-3
• Exams on Wednesday—be sure that you are
familiar with lab materials (diagrams, models,
slides, etc)
• Please see me if you need help with course
material
Structures Observed in Slides of Bone
Tissue
• Osteon: concentric rings (lamellae) of calcified matrix
surrounding a vertically oriented blood vessel
• Lamellae
– Concentric lamellae: layers of matrix concentrically arranged
around a central canal
– Interstitial lamellae: older osteons that have been partially
removed during tissue remodeling
• Central/Haversian canal: longitudinal channels in bone tissue
through which blood vessels, nerve fibers, and lymphatics
pass
• Lacuna: small cavity or depression in a tissue such as bone,
cartilage and the erectile tissues
• Canaliculi: canals filled with ECF that connect osteons
• Volkman’s canals: run perpendicular to central canal to
convey blood vessels to deeper osteons
Structures Observed in Slides of Bone
Tissue
• Periosteum: CT that covers all bones
– Outer fibrous layer and inner osteogenic layer
(stem cells lay matrix at surface)
• Dense irregular CT
Cells of Bone Tissue
• Osteoblast: bone-forming cell that arises from an
osteogenic cell, deposits bone matrix and
eventually becomes an osteocyte
• Osteocyte: mature bone cell formed when an
osteoblast becomes surrounded by its own matrix
and entrapped in a lacuna
• Osteoclast: macrophage of the bone surface that
dissoves the matrix and returns minerals to the ECF
Compact Bone
Lacuna with
osteocyte
Concentric
lamellae
Central canal
Interstitial
lamellae
Zones of Growth in Epiphyseal Plate
• Zone of resting cartilage
– anchors growth plate to
bone
• Zone of proliferating cartilage
– rapid cell division
• Zone of hypertrophic cartilage
– cells enlarged & remain in
columns
• Zone of calcified cartilage
– thin zone, cells mostly dead
since matrix calcified
– osteoclasts removing matrix
– osteoblasts & capillaries
move in to create bone over
calcified cartilage
Growth at epiphyseal plates
Hyaline cartilage
Proliferating cartilage
Hypertrophic cartilage
Calcified cartilage
Spongy bone (trabeculae)
Compact bone
Periosteum
Proliferative Cartilage
Calcified Cartilage
Functional Classification of Joints
• Synarthrosis (fibrous) joints
– No joint cavity
– Sutures: immovable; bind bones of skull together
– Gomphoses: tooth to socket (periodontal ligament
allows movement to sense how hard we bite)
– Syndesmoses: tibia and fibula or radius and ulna;
ROM differs greatly among each one but this is
most mobile
Functional Classification of Joints
• Amphiarthrosis (cartilaginous) joints
– No joint cavity
– Synchondrosis: bones bound by hyaline cartilage;
epiphysis and diaphysis (epiphyseal plate) or first
rib to the sternum (costal cartilage)
– Symphyses: bones bound by fibrocartilage; pubic
symphysis or intervertebral discs
Functional Classification of Joints
• Diarthrosis (synovial) joints
– Have joint cavity
– Bones separated by a film of synovial fluid
– Most abundant and freely movable joints
– Jaw, elbow, hip and knee joints
Synovial Joints
Knee Joint
Exercise and Articular Cartilage
• Exercise warms synovial fluid:
1. Becomes less viscous and more easily absorbed by the
articular cartilage
2. Cartilage swells and provides a more effective cushion
against compression
• Cartilage is non-vascular, so repetitive compression
is important to its nutrition and waste removal
– Compressed  fluid and metabolic wastes squeezed out
– Weight released  cartilage absorbs synovial fluid
(oxygen, nutrients)
• Weight-bearing exercise: builds bone mass and
strengthens the muscles that stabilize many joints
Lab Objectives
• Ensure that you complete each section of your lab
guide:
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Histology  Use Unit 2 Lab 4 ppt (faculty website)
Articulations
Tibofemoral joint (including review for knee)
Movements at synovial joints
X Ray films
Anatomy of a long bone
Auditory ossicles
Please be careful with slides and bones. Ask for assistance if
needed. Enjoy!