Shared Flashcard Set

Details

Cartilage and Bone
Cartilage and Bone
67
Medical
Graduate
10/21/2009

Additional Medical Flashcards

 


 

Cards

Term
APPOSITIONAL GROWTH
Definition

1. Forms cartilage through the secretion of molecules by apposing layers of cells that serve to embed the cells within a matrix

2. Differentiation of cells from inner layer of perichondrium

3. Perichondrium is required

4. Chondroblasts differentiate into chondrocytes

5. Cartilage added around perimeter of cartilage plate

Term
INTERSTITIAL GROWTH
Definition

1. Due to matrix pliability, cells of cartilage retain the ability to divide and grow from within the matrix

2. Growth from within

3. Gel-like matrix required

4. Isogenous groups formed

5. Cell number and matrix increase within the cartilage plate

Term
ENDOCHONDRAL GROWTH
Definition

Growth of bones from a template of cartilage (long bones)

Term
INTRAMEMBRANOUS GROWTH
Definition

Bones formed by adding apposing layers of cells that embed themselves in matrix (flat bones)

Term
LACUNAE
Definition

1. Found in both cartilage and bone

2. Cavities in which mature cells, surrounded by matrix comprised of collagens and ground substance, reside

Term
STRUCTURAL ELEMENTS OF CARTILAGE
Definition

1. Chondroblasts

2. Chondrocytes

3. Matrix

4. Perichondrium

Term
CHONDROGENIC CELLS
Definition

1. Spindle-shaped cells derived from mesenchymal cells

2.  Sparse cytoplasm, little RER and golgi, abundant ribosomes

3. Potential to differentiate into chondroblasts

Term
CHONDROBLASTS
Definition

1. Immature cells derived from mesenchymal stem cells in the center of chondrification or chondrogenic cells in inner layer of perichondrium

2. Plump, polarized cells actively synthesizing matrix components

3. Secretion of matrix occurs on side of cell facing cartilage plate

Term
CHONDROCYTES
Definition

1. Chondroblasts that are surrounded by matrix

2. Located in lacunae

3. Appear as isogenous groups

4. Synthesize chondronectin, collagen, and glycosaminoglycans

Term
MATRIX
Definition

1. Type II collagen is predominant

2. Ground substance

Term
GROUND SUBSTANCE
Definition

1. Mostly water (70%), chondronectin, and proteoglycans

2. Chondronectin serves as critical adhesive glycoprotein (type II collagen, GAGs, integrins, etc.)

3. Abundant negative charges (attracts cations, which attracts water)

4. GAGs form electrostatic bonds with collagen and form a cross-linked network to further increase the ability to resist tensile forces

Term
TERRITORIAL MATRIX
Definition

More intense basophilic staining immediately around the lacunae (rich in GAGs)

Term
INTERTERRITORIAL MATRIX
Definition

Appears bluish-gray, characteristic of hyaline cartilage

Term
PERICHONDRIUM
Definition

1. A dense connective tissue sheat surrounding cartilage

2. Consists of immature cells, chondroblasts, fibroblasts, and Type I collagen

3. Inner chondrogenic layer differentiates into chondroblasts and secretes matrix

4. Vascularized, and supplies nutrients to cartilage cells

Term
TYPES OF CARTILAGE
Definition

1. Hyaline cartilage

2. Elastic cartilage

3. Fibrocartilage

Term
HYALINE CARTILAGE
Definition

1. Located in walls of large airways (nose, larynx, trachea) ventral ends of ribs, and articular surfaces of bones within joints

2. Provides stiff but somewhat flexible support and reduces friction between bony surfaces

3. Has perichondrium

4. Type II collagen

 

Term
ELASTIC CARTILAGE
Definition

1. Located in auricle of  ear, epiglottis, and larynx

2. Provides support, but tolerates distortion without damage and returns to original shape

3. Has perichondrium

4. Type II collagen and elastic fibers

Term
FIBROCARTILAGE
Definition

1. Possesses a matrix with aligned bundles of dense collagen fibers interspersed with linear rows of chondrocytes in lacunae

2. Located in areas subject to much stress or weight bearing (intervertebral discs, attachments of some ligaments to bones, menisci of knees, symphysis of pubis)

3. NO PERICHONDRIUM, SO NO APPOSITIONAL GROWTH

4. Type I collagen (stains acidophilic), scant matrix

5. Chondrocytes in fibrocartilage derived from fibroblasts

Term
STRUCTURAL ELEMENTS OF BONE
Definition

1. Cells: osteoprogenitor cells, osteoblasts, osteocytes, osteoclasts

2. Fibers: primarily Type I collagen

Term
GROUND SUBSTANCE OF BONE
Definition

Extracellular matrix with hydroxyapatite crystals, proteoglycans and proteins

Term
OSTEOPROGENITOR CELLS
Definition

1. Serve as precursors for bone cells

2. Derived from mesenchymal (retain ability to undertake mitosis)

3. Differentiate into osteoblasts; high oxygen tension

4. Scant cytoplasm with abundant free ribosomes

Term
OSTEOBLASTS
Definition

1. Responsible for the synthesis of organic components of bone matrix (called "osteoid" prior to mineralization)

2. Synthesize collagens, proteoglycans, glycoproteins

3. Receptors for parathyroid hormone

4. Located in sheet of cuboidal cells apposed to growing edge of bone in periostem and endosteum

5. Highly synthetic with abundant RER (basophilic), polarized

6. Extend processes apposing osteoblasts and form desmosomal junctions

7. Differentiate into osteocytes

Term
OSTEOCYTES
Definition

1. Responsible for maintaining bone matrix via synthesis of matrix components

2. Located in compact bone and cancellous bone

3. Occupy lacunae and extended processes form canaliculi

4. Nutrients and metabolites from capillaries exchanged through canalculi and lacunae

5. Death results in resorption of matrix

Term
BONE MATRIX COMPONENTS
Definition

1. Organic matter

a. Type I collagen

b. Proteoglycans

c. Glycoproteins (osteocalcin, osteospondin, sialoproteins)

2. Inorganic matter

a. Calcium and phosphorus, also bicarbonate, citrate, magnesium, sodium, and potassium

b. Hydroxyapatite crystals, calcium phosphate

c. Minerals give bone its characteristic hardness

Term
RICKETS
Definition

1. Results from calcium or vitamin D deficiency in children

2. Vitamin D is necessary for the intestinal absorption of calcium

3. Rickets is characterized by improper calcification of bone matrix and formation of distorted bone spicules, leading to slow bone growth and deformed shape

Term
OSTEOMALACIA
Definition

1. The adult form of Rickets

2. Softening of bones is characterized by deficient calcification of newly formed bone and partial decalcification of already calcified matrix

3. Bones become soft, flexible and brittle, cauisng deformities different from Rickets

4. May be aggravated during pregnancy due to increased demands for calcium from (maternal and fetal)

Term
BONE FIBERS
Definition

1. Type I collagen

2. Fibers arranged helically with respect to long axis of Haversian canal

Term
CONNECTIVE TISSUE SHEATHS FOR BONE
Definition

1. Periosteum

2. Endosteum

 

Term
PERIOSTEUM
Definition

1. On bone surface, except articulating surfaces

2. Outer dense fibrous CT layer with fibroblasts

3. Inner layer with osteoprogenitor cells and osteoblasts

Term
ENDOSTEUM
Definition

1. Central (marrow) cavity of bone

2. Usually a single layer of osteoblasts

3. Osteoclasts in Howship's lacunae

Term
6 TYPES OF BONE
Definition

1. Long bones

2. Flat bones

3. Irregular bones

4. Short bones

5. Sesamoid bones

6. Sutural bones

Term
LONG BONES
Definition

1. Bulbous end (epiphysis), which is spongy bone with a thin shell of compact bone (cartilage on articulating surface)

2. Diaphysis= cylindrical part between the two epiphyses made up of compact bone surrounding spongy bone lining marrow cavity

3. Ex. humerus of arm

Term
COMPACT BONE
Definition

1. Primarily matrix deposited in concentric lamellae

2. Lacunae, each filled with 1 osteocyte

3. Cytoplasmic extensions radiating out from each lacunae (canalculi)

4. Lamellae organized into Haversian systems (osteon), which contain blood vessels, lymphatics, and loose CT

5. Interstitial lamellae (old lamellae in disrepair), inner and outer circumferential lamellae (just inside periosteum and just under the endosteum, respectively)

6. Volkmann's canal-like Haversian canal, but perpendicular to osteon

7. Periosteum and endosteum

Term
SPONGY BONE
Definition

1. Displays a meshwork of trabeculae separating cavities filled with marrow

2. Essentially identical to compact bone, but with fewer Haversian systems, only an endosteum, and osteoclasts in Howship's lacunae

Term
FLAT BONES
Definition

1. Inner and outer layer (plates) of compact bone enclosing a middle layer of spongy bone

2. Ex. parietal bone

Term
IRREGULAR BONE
Definition

1. Spongy bone enclosed by thin layer of compact bone

2. Ex. vertebra

Term
SHORT BONES
Definition

1. Like flat bones, with an inner and outer layer of compact bone surrounding spongy bone

2. Ex. carpal and metacarpal bones

 

Term
SESAMOID BONES
Definition

1. Found in locations where tendon passes over a joint

2. Ex. patella

Term
SUTURAL BONES
Definition

1. Ex. sutures in the skull

Term
PERIOSTEUM
Definition

Outside compact bone, except area of joint articulation

Term
PRIMARY BONE
Definition

1. First type synthesized during development and repair

2. Irregularly arranged collagen bundles, less minerals, more osteocytes than secondary bone

Term
SECONDARY BONE
Definition

1. Usually in adults

2. Classified as spongy or cpmpact based largely on arrangement of collagen fibers (arranged in parallel lamellae in spongy bone and concentric lamellae surrounding a canal in compact bone)

Term
BONE DEVELOPMENT
Definition

1. Bone always develops by replacement of preexisting connective tissue

2. Growth is appositional (intramembranous ossification and endochondrial ossification)

3. Primary bone laid down as network of trabeculae, then converted to secondary bone (usually compact) by filling in the spaces between the trabeculae

4. Areas of primary bone, resorption, and secondary bone appear side by side

Term
INTRAMEMBRANOUS OSSIFICATION
Definition

1. Leads to formation of flat bones

2. Participates in growth of short bones

3. Contributes to the thickening of long bones

4. Occurs in consecutive steps that overlap

Term
STEPS OF INTRAMEMBRANOUS OSSIFICATION
Definition

1. Primary ossification center- layer of mesenchymal tissue forms and cells contact each other

2. Mesenchymal cells differentiate into osteoblasts and regions of mesenchymal cells with continuous mitotic activity form periosteum and endosteum

3. Osteoblasts secrete osteoid (noncalcified matrix) away from osteoprogenitor cells

4. Osteoblasts with matrix become osteocytes; collagen fibers randomly oriented and primary bone is formed

5. Calcium phosphate deposits in bone matrix, calcifying matrix

6. Spicules form (islands of developing bone)

7. Osteoblasts incorporated into bone

8. Secondary bone is formed and collagen fibers become more regularly arranged in areas to be compact bone

9. Central vascular CT surrounding spicules of bone is transformed into hematopoietic tissue in areas to become spongy bone

Term
ENDOCHONDRAL OSSIFICATION
Definition

1. Involves the replacement of hyaline cartilage template by bone

2. Involved in the formation of short and long bones (lengthen)

3. Begins with a cartilage model of bone already developed

4. Model is formed by both interstitial and appositional growth methods

Term
STEPS OF ENDOCHONDRAL OSSIFICATION
Definition

1. Hyaline cartilage model

2. Periosteal bone collar forms

3. Hyaline cartilage begins to calcify

4. Metaphyseal trabeculae no longer needed and calcified cartilage remains

5. Formation of epiphyseal trabeculae and secondary ossification center

6. Lower epiphyseal plate disappears adn epiphyseal and metaphyseal trabeculae fuse

7. Upper epiphyseal plate disappears and metaphyseal trabeculae fuse

Term
OSTEOGENIC (PERIOSTEAL) BUD
Definition

1. Penetrates hole in bone collar made by osteoclasts

2. Consists of blood vessels carrying osteoprogenitor cells and hematopoietic cells

Term
SECONDARY OSSIFICATION CENTER
Definition

1. Forms in the epiphysis at each end of the forming bone (no bone collar formed)

2. Ossification spreads in all directions except for articular cartilage at bulbous ends of long bones and the epiphyseal plate

Term
EPIPHYSEAL PLATE
Definition

1. A portion of cartilage that connects the epiphysis to the diaphysis

2. Retains same thickness during maturation, and is responsible for all subsequent growth in long bones

3. Eventually replaced by bone (end of potential for longitudinal growth)

Term
ZONES OF BONE DEVELOPMENT
Definition

1. Resting zone

2. Proliferative zone

3. Maturation or hypertrophic zone

4. Calcification zone

5. Ossification zone

Term
RESTING ZONE
Definition

1. Normal hyaline cartilage

2. Random chondrocytes with a few isogenous groups

Term
PROLIFERATIVE ZONE
Definition

1. Rapidly dividing chondrocytes form columns parallel to long axis of bone via process of interstitial growth (no perichondrium on articulating surfaces)

2. Looks like stack of dimes

 

Term
MATURATION OR HYPERTROPHIC ZONE
Definition

1. Nondividing chondrocytes continue to enlarge and become vacuolated

2. With the cell enlargements, lacunae enlarge, matrix diminishes, adn the "cytes" are separated by thin septa of matrix

Term
CALCIFICATION ZONE
Definition

1. Thin septa of cartilage (basophilic) become calcified by deposition of calcium phosphate salts

2. With mineralization, the diffusion is inhibited and chondrocytes die

Term
OSSIFICATION ZONE
Definition

1. As chondrocytes degenerate, blood vessels invade the area and bring osteoprogenitor cells

2. Differentiate into osteoblasts and mature into osteocytes that deposit bone matrix that is calcified

3. Bone spicules form

4. Presence of calcified cartilage that stains blue, encased in bone matrix that is stained red

Term
BONE GROWTH IN WIDTH
Definition

1. Occurs by intramembranous ossification in the diaphysis

2. Shaft  build by sub-periosteal and sub-endosteal intramembranous bone formation

 

Term
BONE REMODELING
Definition

Results in the formationof new Haversian systems and the resorption and deposition of bone

Term
BONE DEPOSITION
Definition

1. Associated with periosteum and endosteum for intramembranous ossification

2. Entrance of blood vessels increases osteoblastic activity and the formation of new Haversian systems

Term
BONE RESORPTION
Definition

1. Associated with osteoclasts in marrow cavity

2. Parathyroid hormone binds to osteoblasts, make RANKL, binds to RANK receptor on osteoclast precursors, stimulation to increase osteoclasts

Term
BONE REPAIR
Definition

1. Localized hemorrhaging fills zone of injury

2. Haversian system become necrotic

3. Blood clot solidifies and cells (fibroblasts) and small blood vessels form granulation tissue

4. Internal callus forms-clot invaded by osteoprogenitor cells from endosteum and multipotential cells from bone marrow

5. Osteoprogenitor cells differentiate and make bone

6. External callus forms and grows

7. Primary bone forms and becomes secondary bone

8. Resorption of callus

Term
OSTEOPOROSIS
Definition

1. Bone resorption is more prominent than bone formation

2. Enhanced bone resorption, decreased bone formation or both

3. Bone becomes more porous

4. Paget's disease-uncontrolled osteoclastic activity

Term
SCURVY
Definition

1. Condition of vitamin C deficiency

2. Inhibits matrix formation, distorts chondrocytes, and interferes with repair of fractures by altering collagen deposition

3. Bleeding gums and loosening of teeth

Term
HYPERPARATHYROIDISM
Definition

1. Due to excess production of parathyroid hormone

2. Marked resorption of bone with decalcification, elevated blood calcium, and abnormal deposits of calcium in several orgagns (metastatic calcification)

Term
SLIPPED DISC
Definition

1. Herniation of an intervertebral disc

2. Rupture of annulus fibrosis and expulsion of nucleus pulposes, causing disc to flatten

3. Disc can slip from its position between vertebrae and compress spinal cord

4. Most common in posterior region, which contains fewer collagen fibers

5. Lower back pain

Term
OSTEOARTHRITIS
Definition

1. A degeneration of articular cartilage due to excessive wear and tear

2. Eventual bone to bone trauma leads to a painful swollen joint

Supporting users have an ad free experience!