Cartilage and BoneLabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. SummarySEM of trabecular/cancellous bone. Inserm.
Cartilage and Bone
1. Cartilage is a specialized type of solid connective tissuewhich, along with bone, is distinguished by the relativerigidity of its extracellular matrix (ECM); it is easilydistinguishable from bone by its avascularity; it providesflexible support to tissues (e.g., ear, nose, larynx).
2. Types of cartilage (hyaline, elastic, and fibrocartilage) aredistinguished by the characteristics of their respectiveECM (e.g., the dominant type of fiber).
3. Bone is a specialized type of solid connective tissuecharacterized by a mineralized ECM that stores calciumand phosphate.
4. Woven bone (immature) differs from lamellar bone(mature) in its collagen fiber arrangement; all new boneis woven, but it becomes remodeled into lamellar bone,with few exceptions.
5. Lamellar bone has organized ECM sheets (lamellae); thedense bone that forms the outer cortex of most bones ofthe body is referred to as cortical bone; while the less-dense, inner bone which is not as compacted but insteadarranged in a lattice-like configuration is referred to ascancellous bone.
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Bone Formation and Joints
1. Bone formation occurs via two basic mechanisms:
a. Intramembranous ossification forms bonewithin mesenchyme (“membrane”).
b. Endochondral ossification forms bone byreplacing a cartilage model.
2. Regardless of the mechanism, all new bone is wovenbone which is remodeled into lamellar bone (eithercompact or trabecular), with organized sheets of bone(lamellae), by osteoclast and osteoblast activity.
3. Joints are places where bones meet (articulate),allowing at least the potential of bending or movement;examples include synovial joints (diarthrosis) andintervertebral joints.
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Learning Objectives I – Cartilage and Bone
1. Understand the variations in structure and function of the three majortypes of cartilage, with regard to both the cellular and extracellularelements.
2. Understand the key ultrastructural features of the chondroblast and howthey relate to function.
3. Understand the structural features and functions of osteogenic cells:osteoblasts, osteocytes, and osteoclasts.
4. Know the major differences in structure and function between woven andlamellar bone, and between compact and cancellous bone.
5. Understand the structure and composition of an osteon and how it isformed.
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Learning Objectives II – Bone Formation and Joints
1. Understand the differences and similarities between intramembranousand endochondral bone formation and the key function of the periosteumin bone growth.
2. Understand the organization of the epiphyseal growth plate and its role inendochondral bone formation and growth of long bones.
3. Understand the structure of a typical synovial joint, including the natureand functions of the synovium.
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Keywords
Articular cartilageBoneCanaliculiCancellous boneCartilageCentral (Haversian) canalChondroblastsChondrocytesCompact boneElastic cartilageEndochondral ossificationEndosteumFibrocartilageGrowth plateHaversian systemHowship’s lacunaeHyaline cartilageIntervertebral jointInterstitial lamellaeIntramembranous ossificationJoint
LacunaeLamellaeLamellar boneMarrowOsteoblastOsteoclastsOsteocyteOsteoidOsteonPerforating (Volkmann’s) canalPerichondriumPeriosteumSynovial jointSynoviumTrabeculaeWoven boneZone of calcificationZone of hypertrophyZone of osteogenesisZone of proliferationZone of reserve cartilage
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 2: Trachea, Trichrome
look here forhyaline cartilage
what kind of epithelium lines the
lumen of the trachea?
thyroid gland
perichondrium
lumen
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 2: Trachea, Trichrome
hyalinecartilage
perichondriumperi = “around”chondrium = “cartilage”
hyaline (Gr. “glassy”) cartilage is the most common type of cartilage in the body; it contains the smallestproportion of fibers in the ECM (primarily type II collagen), giving it a fairly homogenous, glassy appearance
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 2: Trachea, Trichrome
perichondrium is dense regular CT essential for appositional growth and maintenance of cartilage; it consistslargely of type I collagen, fibroblasts, and progenitor cells for chondroblasts that divide and differentiate intochondrocytes; hyaline cartilage is three-dimensionally surrounded by perichondrium, expect as articularcartilage in joints; elastic cartilage also has perichondrium, but fibrocartilage does not
perichondrium
hyaline cartilagenotice the lack of vasculature within the cartilage; it relies
on diffusion from vessels in the perichondrium, limiting the maximal cartilage thickness
fibroblast
chondroblast
chondrocyte
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 2: Trachea, Trichrome
chondroblast
chondrocyte (cell) located in lacuna (space)
perichondriumhyaline cartilage
fibroblast
appositional growth occurs at the interface of the perichondrium and the cartilage as chondroblasts, fromperichondrial cells, actively synthesize new cartilage matrix; they secrete ECM components until they encasethemselves within the matrix – the small remaining, matrix-free space that the cell inhabits is called a lacuna(Lt. “little lake”); once encased, the cells are referred to as chondrocytes, which continue to synthesize andmaintain ECM components; both types of cells have basophilic cytoplasm rich in rER for collagen synthesisterminology note: the suffix –blast identifies immature, not fully-differentiated cell types; those cells differentiateinto mature, terminal cells identified by the suffix –cyte; fibroblasts are a slight exception to this rule, as the termfibrocyte is seldom used and has been newly applied to types of circulating mesenchymal progenitor cells
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 140: Trachea, H&E
perichondriumhyaline cartilage small clusters of
chondrocytes are referred to as isogenous groups and reflect interstitial growth
darker-staining territorial matrix surrounds isogenous groups
lighter-staining interterritorial matrix is located between groups of chondrocytes and reflects concentration differences in ECM components
the empty appearance of some lacunae is an artifact of slide preparation, as the cells either pull away from the matrix or are lost
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 87: Epiglottis, Masson AF
elastic cartilage
perichondrium
lamina propria(loose CT)
non-keratinzedstratified squamousepithelium
the epiglottis (protects entrance to larynx) consists of a core of elastic cartilage surrounded by loose CT and acovering of stratified squamous epithelium; elastic cartilage is similar to hyaline cartilage except that it containsan abundant network of elastic fibers in addition to type II collagen; visualization of the elastic fibers usuallyrequires special stains; it is found in the auricle of the ear, walls of the external auditory canals (auditorymeatus), auditory (Eustachian) tubes, epiglottis, and cartilages in the larynx
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 56: Elastic Cartilage, AFelastic cartilage
perichondrium
the separation of the tissue is an artifact of
slide preparation
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 25: Auditory Meatus, H&E
distinguishing elastic cartilage from hyaline cartilage can be tricky in H&E without specialized stains to showthe elastic fibers; however: the elastic fibers provide a more heterogeneous appearance to the cartilage vs. thesmooth, glassy appearance of hyaline; elastic cartilage has a greater density of chondrocytes with less ECMbetween them than in hyaline; and the chondrocytes in elastic cartilage tend to be larger than in hyaline
elastic cartilage
perichondrium
keratinized stratified squamous epithelium
hair follicle
sebaceous gland
ceruminous (earwax) gland
skin
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide Overview
Slide 131: Fibrocartilage, H&ESlide Overview
the slide shows the pubic symphysis, which is the cartilaginous joint linking the pubic bones of the pelvic girdle;beyond the fibrocartilage, examples of many other tissue types and structures can be identified
tendon
periosteum
endochondral ossification
bone marrow within trabecular bone
adipocytes
skeletal muscle
adipocytes
attachment of muscle to the bone
skeletal muscle
cortical bone
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 131: Fibrocartilage, H&E
fibrocartilage is a combination of dense regular CT (type I collagen) and hyaline cartilage (type II collagen);the collagen bundles and chondrocytes are generally arranged in rows parallel to the direction of functionalstress; unlike hyaline and elastic cartilage, there is no distinct surrounding perichondrium in fibrocartilage; itis found in intervertebral discs, attachments of certain ligaments, and in the pubic symphysis
collagen bundle
chondrocyte in lacuna
fibroblast
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide OverviewSlide 34: Bone, H&E
sections (1) and (2) are two rib segments from a fetal/newborn rabbit; (1) gives an example of a bone fractureand repair processes (the callus is a temporary formation of highly proliferative fibroblasts and chondroblastsextending from the periosteum down into the fracture to form new bone); (2) gives an example of endochondralossification (EC Oss) bone growth
1
2
fracture
callus
hyaline cartilage
EC Oss
corticalbone
trabecular bone
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide OverviewSlide 34: Bone, H&E
from the outside: (P) is periosteum, the dense connective tissue surrounding bone, with clearly visible collagenbundles; (Act P) is an area of more active periosteum with lots of cellular differentiation occurring; (Wb) iswoven or primary bone; (HC) are areas of hyaline cartilage; (M) is marrow with abundant blood cells; (Tb) ismature, lamellar trabecular bone; close examination shows endosteum on the edge of the bone bordering themarrow
Tb
Wb
M
Act P
P
HC
M
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide OverviewSlide 34: Bone, H&E
from the outside (top): (P) is periosteum with clearly visible collagen bundles; (Cb) is cortical bone with alamellar arrangement of bone matrix and osteons; (M) is marrow with abundant blood cells; (Tb) is trabecularbone with endosteum on the edge of the bone bordering the marrow; (Wb) is woven or primary bone which isnewly-formed bone with an irregular arrangement of collagen fibers (i.e., not lamellar)
PCb
M
Tb
PWb
Tb
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 34: Bone, H&E
periosteum is dense regular CT that surrounds the outer surfaces of bone (except at articulations) and attachesto the outer lamellae via collagenous Sharpey’s fibers (not always seen); it contains osteoprogenitor cells whichare capable of differentiating into osteoblasts and forming new bone (appositional growth); blood vessels passbetween the periosteum and bone through perforating (Volkmann’s) canals, with most blood directionallyflowing from the marrow cavities and draining out through periosteal veins
Slide Overview
periosteum(dense regular CT)peri = “around”osteum = “bone”
fibroblast
osteoprogenitor cells(osteoblasts)
osteocyte in lacuna
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide OverviewSlide 34: Bone, H&E
endosteum lines all the internal surfaces of bone (marrow cavities, osteons, and perforating canals); it isgenerally only a single cell-layer thick and consists of osteoblasts and bone-lining cells; inactive osteoblastsand bone-lining cells are generally flattened with only dark, elongated nuclei being visible; osteoblasts thatare actively secreting bone ECM components are much more round or cuboidal in appearance
endosteum
endosteum
osteocyte (cell) in lacuna (space)
hematopoietic cord where blood cell development occurs
red blood cells in vascular sinusoidhow new blood cells leave the marrow
stroma of bone marrow
trabecular bone
trabecular bone
marrow
-filled cavity
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide OverviewSlide 34: Bone, H&E
trabecular bone
marrow
osteoidlighter-stained area between endosteum and mature bone
endosteum with osteoblasts(round, plump cells)
osteocyte in lacuna
osteoid is the collagen-rich, non-mineralized precursor to true bone ECM; it is secreted by osteoblasts, such asthose of the endosteum, during bone growth, repair, and remodeling; the osteoblasts subsequently calcify theosteoid into hard bone matrix, and in the process, they become trapped in the matrix (in lacunae) and becomeosteocytes (similar to the process of chondroblasts becoming chondrocytes in cartilage)
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide OverviewSlide 34: Bone, H&E
osteoclasts (Gr. “bone breaking”) are large, acidophilic, multinucleated cells (generally 5-20 nuclei); they arecritical for bone remodeling and resorb bone by secreting organic acids which dissolve hydroxyapatite andlysosomal enzymes which break down the osteoid matrix; at the bone surface, osteoclasts are found withinsurface depressions caused by the resorption of bone called Howship's lacunae (or resorption bays)
osteoclast within Howship’s lacunaosteoclast within Howship’s lacuna
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formation
b. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Intramembranous Ossification
1. Primary center of ossification: mesenchyme cells osteoblasts
2. Osteoblasts begin depositing bone matrix to form trabeculae or spiculesof woven bone (immature bone) extending radially from the ossificationcenter; osteoblasts become osteocytes
3. Marrow develops in spaces between trabeculae
4. Periosteum and endosteum develop from mesenchyme membrane onsurfaces of new bone
5. Woven bone is remodeled to form lamellar bone (compact and trabecular)
Slide 130: Fetal SkullLabs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formation
b. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Side View Frontal Viewdeveloping tooth with surrounding intramembranous bone development of the jaw
tongue in the oral cavity
nasal cavity with cartilaginous nasal septum in the middle; surrounded by intramembranous bone development of the skull
Slide 130 – Fetal Skull
Slide Overview
see Slide 12a (464) and Slide 32 (NW) for
additional examples
Slide 130: Fetal SkullLabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formation
b. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
trabeculae (or spiculae) of new woven bone are
dispersed within mesenchyme
look for osteoblasts on the surfaces of the bone, while osteocytes can be
seen contained within the lacunae of the bone
mesenchyme(primitive CT)
Slide 130: Fetal SkullLabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formation
b. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summaryeven though hyaline cartilage is present adjacent to the mesenchyme, it is not involved in the formation ofthe new bone seen occurring here via intramembranous ossification (not endochondral ossification)
hyalinecartilage
trabeculae ofwoven bone
(new bone)
periosteum(dense CT)
specialized olfactory epithelium
mesenchyme
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Endochondral Ossification
Note: Because the rates of chondrocyte proliferation (in zone of proliferation) and destruction (in zone ofcalcification) are approximately equal, the epiphyseal plate does not change in thickness; instead, it is“displaced” away from the middle of the diaphysis, resulting in growth in length of the bone.
1. Zone of Reserve Cartilage: hyaline cartilage acts as source of cartilage to undergo ossification
2. Zone of Proliferation: normal chondrocytes multiply
3. Zone of Hypertrophy: chondrocytes enlarge and align
4. Zone of Calcification:* cartilage matrix calcifies providing scaffold for new bone; chondrocyte degenerate (apoptosis)
5. Zone of Ossification and Resorption:* osteoblasts invade and bone is deposited on the calcified matrix; osteoclasts begin the remodeling process
Unlike in intramembranous bone formation, endochondral ossification occurs when a hyaline cartilagemodel is replaced with bone; this more complex method of bone formation provides the benefit of having aload-bearing structure in place (cartilage) before the bone has formed; the bones of the extremities andload-bearing bones of the axial skeleton (e.g., vertebrae) are formed via this method, which can bespatiotemporally separated into the following zones:
Slide 34: Bone, H&ELabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
epiphyseal growth plateepiphysis(end of bone)
diaphysis(shaft of bone)
look here to see endochondral
ossificationhyaline
cartilagewoven bone
marrow
Slide 34: Bone, H&ELabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
zone ofreserve cartilage
zone of proliferation
zone of hypertrophy
zones of calcification & ossification
typical hyaline cartilage chondrocytes form rows or clusters of cells from successive mitotic divisions
chondrocytes greatly enlarge in size
matrix becomes calcified chondrocytes degenerate osteogenic cells and vessels
invade from the bone marrow osteoblasts form new bone
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compacti. Cortical/Compactii. Cancellous/Trabecular
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 13a (464): Bone, H&E
Slide 13 (464): Foot, H&E Slide 15a (464): Joint
Slide 42a (464): Fingertip
primary ossification
centers
Slide 34: Bone, H&ELabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
while endochondral ossification provides a means for bones to lengthen at the epiphyseal growth plate, bonesgrow wider (increase in diameter) via appositional growth at the interface between the bone and thesurrounding periosteum; osteoblasts differentiate from precursor cells and laydown new bone matrix (osteoid)onto the surface of the bone, increasing the overall width; the marrow cavity then also enlarges by resorptionof bone on the endosteal surface
periosteum(dense CT)
bone
osteoid (pale-staining)
osteoblasts
marrow
endosteum
Slide 104: Bone, H&ELabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
during internal remodeling of bone, osteoclasts invade a section of compact bone and resorb enough bone tocreate large resorption canals (often irregularly shaped borders with the dimensions of a new osteon); intothis newly created tunnel, blood vessels and osteoprogenitor cells enter; osteoblasts begin to deposit new bonealong the wall of the tunnel, forming lamellae (Lt. “thin plates”) of new bone; synthesis of new bone continuesfrom the periphery to the center of the canal, with concentric layers (rings) of new bone being deposited untilonly the small central canal of the osteon remains with the neurovascular bundle at the center
osteon
central canal
resorption canal
periosteum
cortical bone
marrow
Slide 13a (464): Developing Bone, H&ELabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
woven bone
new bone, regardless of the process of its formation (e.g., intramembranous or endochondral formation) isconsidered immature due to its lack of organization of its bone matrix (it is non-lamellar bone); because of therandom arrangement of the osteocytes and the interspersed haphazard collagen fiber arrangement, new boneis referred to as woven bone; woven bone will be remodeled into cortical bone and trabecular bone
Slide 12 (464): Decalcified Bone, H&ELabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
resorption canal
endosteum
arrangement of parallel lamellae of bone matrix
osteocyte in lacuna
new woven bone is generally soon remodeled into lamellar bone which is named due to its distinctivelamellated architecture with parallel layers of sheets (lamellae) of bone matrix, as opposed to the haphazard,disorganized matrix arrangement of woven bone; both cancellous/trabecular/spongy and cortical/compactbone are types of lamellar bone
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 104: Bone, H&E
periosteum
cortical bone
a trabecula of cancellous bone(Lt. “lattice”)
marrow(with lots of adipocytes)
cancellous/trabecular/spongy bone is the “sponge-like” network of lamellar bone which extends from theperipheral cortical bone and fills the interior of bones; it consists of a series of interconnected trabeculae(Lt. “beam/timber”) composed of lamellae of bone matrix; the spaces between the trabeculae are continuousand filled with marrow; unlike the marrow shown above, most bones of the body are filled with yellowmarrow which is primarily adipose tissue
Slide 12 (464): Decalcified Bone, H&ELabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
marrowcortical bone
skeletal muscle periosteum resorption canalcentral canal of osteon osteocyte
cortical/compact bone is the compact, dense layer of bone tissue found at the periphery (cortex) of bones; it islargely composed of osteons (or Haversian systems) – functional units – which consist of concentric sheets(lamellae) of bone matrix surrounding a central canal (or osteonal/Haversian canal), which contains the bloodvessels and nerves that supply the osteon; osteon organization is generally only seen in cortical bone, but it maybe seen in large trabeculae of spongy bone; the overall architecture is best observed in ground bone
Slide 32: Ground Bone
look here to see osteons in cross-section(transverse)
look here to see osteons in longitudinal section
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
unlike the previous slides of bone which were chemically decalcified in order to permit them to be sectionednormally like other tissues, ground bone is not fixed but simply allowed to dry and then ground into thinsections; while most of the cells and tissue are lost, this method keeps the calcified bone matrix intact andpermits better appreciation of the bone architecture, especially of the osteons of compact bone
Slide 32: Ground BoneLabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
central canals
outline of2 osteons
Transverse Section
Slide 32: Ground BoneLabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
lamella (sheet) of bone matrix
lacunae (spaces)
canaliculi(faint lines)
central canal
interstitial lamellae
Transverse Section
within each osteon, the concentric lamellae of bone matrix are clearly visible; lacunae, which in living bonecontain osteocytes, occur between the lamellae; from the lacunae, canaliculi (Lt. “small channels”) radiatethrough the lamellae connecting the osteocytes together and to the central canal (with neurovascular bundle);interstitial lamellae are remnants of osteons that have been partially resorbed during bone remodeling
Slide 32: Ground BoneLabs 6/7 – Cartilage and Bone
IUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
perforating (Volkmann’s) canals generally run perpendicular to osteons and provide links betweenindividual central (haversian) canals; they transmit neurovascular bundles between the periosteumand the bone
perforating(Volkmann’s)canals
Transverse Section
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 15a (464): Fetal Joint
look here to see Sharpey’s fibers and attachment of muscle to the bone(still cartilage this early in development)
synovium (synovial membrane) lines the interior of the joint capsule and secretes lubricating fluid into cavity
articular cartilage is similar to hyaline cartilage but lacks a perichondrium
joint cavity
skeletal muscle
periosteum
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 14a (464): Intervertebral Disc, H&E
vertebra(bone of vertebral column)
intervertebral discwith concentric rings of fibrocartilage
thin layer of hyaline cartilage
vertebra(bone of vertebral column)
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Slide 23 (NW): Intervertebral Disc
annulus fibrosus(Lt. “fiber ring”)
concentric rings of fibrocartilage
nucleus pulposus(Lt. “fleshy core”)
gel-like, shock-absorbing tissue at center of disc
this large area of discoloration is an artifact of slide preparation
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Common Confusion:Hyaline vs. Elastic Cartilage
Hyaline cartilage
Hyaline cartilage: most common form of cartilage; located inthe articular surfaces of movable joints, in the walls of largerrespiratory passages, in the ventral ends of ribs, and in theepiphyseal plates of long bones
Look for: (1) homogenous, slightly basophilic matrix; (2)chondrocytes arranged in small clusters of 2-4 cells
Elastic cartilage: similar to hyaline but with elastic fibers inECM providing elasticity to the tissue; found in canal of ear,Eustachian tube, epiglottis, and laryngeal cartilages
Look for: (1) presence of elastic fibers in ECM if specializedstains are used; (2) matrix is more heterogeneous and less“glassy” in appearance; (3) greater cell density, thus less ECMbetween cells; (4) larger chondrocytes than in hyaline
Elastic cartilage
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Common Confusion:Hyaline vs. Fibrocartilage
Hyaline cartilage
Hyaline cartilage: most common form of cartilage; located inthe articular surfaces of movable joints, in the walls of largerrespiratory passages, in the ventral ends of ribs, and in theepiphyseal plates of long bones
Look for: (1) homogenous, slightly basophilic matrix; (2) lackof visible collagen fibers in matrix; (3) lacunae often containtwo or more chondrocytes (isogenous group); (4) lacunaeimmediately rimmed with basophilic matrix (less collagen,more GAGs); (5) generally surrounded by perichondrium(not seen here)
Fibrocartilage: found in intervertebral discs, in attachmentsof certain ligaments, and in the pubic symphysis; it isessentially a combination of hyaline cartilage and dense CT
Look for: (1) collagen fibers in eosinophilic matrix; (2)usually only individual chondrocytes in lacunae; (3) lacunaearranged in rows or clusters; (4) lack of perichondrium
Fibrocartilage
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Common Confusion:Dense Regular CT vs. Fibrocartilage
Dense regular CT
Dense regular connective tissue: prominent in tendons,ligaments, and surrounding tissues and organs; collagenbundles and fibroblasts aligned in parallel to axis of functionalstress
Look for: (1) parallel, closely packed bundles of collagenseparated by very little ground substance; (2) fibroblasts arerelatively sparse and have elongated nuclei lying parallel to thefibers; (3) cytoplasm of fibroblasts is rarely revealed in H&Estains
Fibrocartilage: found in intervertebral discs, in attachments ofcertain ligaments, and in the pubic symphysis; essentially acombination of hyaline cartilage and dense connective tissue
Look for: (1) chondrocytes in lacunae; (2) collagen bundles arefewer, less densely-packed, and interspersed among cartilagematrix; (3) tissue generally lacks as uniformly parallel anorganization as seen in dense CT; (4) few fibroblasts are seen;(5) chondrocyte nuclei are more oval/round, with perinuclearcytoplasm generally evident, than fibroblast nuclei; (6)chondrocytes usually appear in linear clusters surrounded bycartilage matrix
Fibrocartilage
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Common Confusion:Cartilage vs. Bone
Hyaline cartilage
Cartilage: a specialized type of solid connective tissue which,along with bone, is distinguished by its relative rigidity of theextracellular matrix (ECM); hyaline, the most common type, ispictured here
Look for: (1) lack of vasculature, lymphatics, and nerves; (2)large proportion of cells to ECM; (3) chondrocytes may occur aspairs within a lacuna and tend to be clustered together(isogenous groups) reflecting interstitial growth; (4)chondrocytes are usually larger and rounder than osteocytes;(5) matrix is often not uniform and tends to heterogeneouslystain; (6) lack of lamellar architecture
Bone: a specialized type of solid connective tissue which ischaracterized by a mineralized ECM that stores calcium andphosphate
Look for: (1) vasculature; note the central canal (osteon)containing visible erythrocytes; (2) more ECM and fewer cells;(3) osteocytes are singular and spaced apart; (4) osteocytesare smaller and more condensed than chondrocytes; (5) canalsand lamellar organization may be visible
Decalcified bone
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Common Confusion:Woven vs. Lamellar Bone
Woven bone
Woven bone: immature, newly-synthesized bone; all new bone,regardless of process of formation, is woven bone; it lacks anorganized architecture for the fibers in the ECM
Look for: (1) lack of lamellar organization of ECM; (2) greatercell density than mature bone with seemingly randomarrangement of cells; (3) matrix contains more groundsubstance so more basophilic staining; (4) deposit of matrix andremodeling is not uniform giving overall mottled appearance
Lamellar bone: mature bone; remodeled from woven bone byosteoclasts and osteoblast activity; bone matrix is deposited andorganized in lamellae (sheets), either in long parallelarrangements on in concentric rings as in osteonal architecture;both cortical/compact bone and trabecular/spongy are lamellar
Look for: (1) less ground substance in matrix so moreeosinophilic staining; (2) lamellar (sheets) arrangement ofmatrix; (3) in cortical bone, osteons with evident central canals
Decalcified lamellar bone
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Summary
1. Cartilage is a specialized type of solid connective tissue that, along with bone, is distinguishedfrom other CT by the relative rigidity of its extracellular matrix (ECM); it generally grows byeither appositional or interstitial growth; it consists of two major cell types:
a. Chondroblasts are generally located at the periphery of cartilage at the interface with thesurrounding dense CT (perichondrium); they secrete new cartilage matrix forappositional growth of cartilage, eventually becoming encased within the newly-synthesized matrix.
b. Chondrocytes are chondroblasts that have become encased in cartilage matrix; they arelocated in spaces in the matrix called lacunae and are responsible for ECM maintenanceand occasionally for interstitial growth of cartilage.
2. The three types of cartilage (hyaline, elastic, fibrocartilage) are distinguished by thecharacteristics of their matrix (e.g., the dominant type of protein fiber).
3. Bone, like cartilage, is a specialized type of solid connective tissue; however, it is characterizedby a mineralized ECM; newly-formed bone is referred to as woven bone due to its interlacedcollagen fibers; woven bone is replaced by lamellar bone (mature) with organized sheets ofbone matrix.
4. Lamellar bone is classified as either cortical/compact which is dense and located at the cortexof bones, or cancellous/trabecular which is has an intricate meshwork of bone that fills themedulla of bones, with the interconnected spaces within the meshwork are filled with marrow.
5. The functional unit of compact bone is the osteon, consisting of a central canal (containing aneurovascular bundle) and concentric rings of bone matrix called lamellae (osteocytes occupylacunae between adjacent lamellae).
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Summary (cont.)
6. Bone formation occurs via one of two processes: in intramembranous ossification new boneforms directly from mesenchyme tissue, while in endochondral ossification bone tissuereplaces existing cartilage.
7. Bone tissue consists of three major cell types:
a. Osteoblasts derive from osteoprogenitor cells from mesenchyme stem cells; they secretetype I collagen and bone matrix proteins (osteoid) as well as calcify the matrix to formnew bone.
b. Osteocytes are mature osteoblasts which have become encased by osteoid; they are long-lived cells that maintain the bone matrix and are able to communicate via canaliculibetween lacunae with other osteoctes to respond to mechanical stressors on the bone.
c. Osteoclasts are multinucleated cells formed from the fusion of hematopoietic progenitorcells; they are responsible for bone resorption.
Labs 6/7 – Cartilage and BoneIUSM – 2016
I. IntroductionII. Learning ObjectivesIII. KeywordsIV. Slides
A. Cartilage1. Hyaline2. Elastic3. Fibrocartilage
B. Bone1. General Overview2. Formation and Growth
a. Intramembranous formationb. Endochondral formationc. Appositional growthd. Internal remodeling
3. Typesa. Wovenb. Lamellar
i. Cancellous/Trabecularii. Cortical/Compact
C. Joints1. Synovial2. Intervertebral
V. Summary
Cartilage and Bone Tissue Compare and Contrast
Terms Compare and Contrast (Similarities? Distinctive differences?)
Cartilage vs. Bone
Hyaline vs. Fibrocartilage
Chondroblast vs. Chondrocyte
Periosteum vs. Endosteum
Appositional vs. Interstitial growth
Cortical vs. Spongy bone
Woven vs. Lamellar bone
Intramembranous vs. Endochondral oss.
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