Ch. 6 Skeletal System Flashcards
Hyaline cartilage
- most intimately associated with bone
- contains perichondrium, chondroblast, lacuna, chondrocyte, matrix
Hyaline cartilage
Chondroblast
-produce a matrix surrounding themselves
Hyaline cartilage
Chondrocyte
-chondroblast turns into this after the matrix surrounds it
Hyaline cartilage
Lacuna
-a rounded cell that occupies space within the matrix
Hyaline cartilage
Perichondrium
- double layered connective tissue sheath covering most cartilage
- outside layer
Appositional growth
- main area of growth in cartilage
- chondroblasts in the perichondrium ass new cartilage to the outside edge of the existing cartilage
Interstitial growth
- very slow process in cartilage
- chondrocytes within the tissue divide and add more matrix between existing cells
Bone Anatomy
bone matrix
- a mineral (hydroxyapatite) which is inorganic material of a calcium phosphate crystal
- collagen and proteoglycans is the organic material
- the inorganic and organic materials provide strength
Bone Anatomy
osteoblasts
- bone forming cells
- produce collagen and proteoglycans which are packaged into vesicles by the Golgi apparatus and released from the cell by exocytosis
Bone Anatomy matrix vesicles (-blasts)
-membrane bound sacs formed when the plasma membrane buds and pinches off
Bone Anatomy
ossification
- osteogenesis
- formation of bone by osteoblasts
Bone Anatomy
osteocytes
- all connected, sharing nutrition
- part of a network (communicating cytoplasmically)
- an osteoblast turns to this after becoming surrounded by the matrix
Bone Anatomy
canuliculi (-cytes)
-little canals that occupy the spaces by the oseocyte cell process
Bone Anatomy
osteoclasts
-responsible for the reabsorption, or breakdown, of bone
Bone Anatomy
osteochondral progenitor cells
- mesenchymal stem cells form these which turn into chondroblasts or osteoblasts
- located in the inner layer of the perichondrium and in the layers of connective tissue that cover bone
Woven bone
- collegan fibers are randomly oriented in many directions
- quick making of new bone after a breakage
Lamellar bone
- mature bone that is organized into thin sheets or layers called lamellae
- woven bone is remodeled into this
Spongy bone
-consists of interconnecting rods or plates of bone called trabeculae
Spongy bone
trabecula
- there is a limit to size due to blood vessels carrying nutrients
- consists of several lamellae with osteocytes located in lacunae
Compact bone
-denser and has fewer spaces than spongy bone
Concentric lamellae
-circular layers of bone matrix that surround a common center
Circumferential lamellae
- the outer surfaces of compact bone
- thin plates that extend around the bone
Interstitial lamellae
-remnants of concentric or circumferential lamellae that were partially removed during bone remodeling
Osteon
- haversian system
- consists of a single central canal, its contents and associated concerntric lamellae and osteocytes
Perforating canals
-canals that allow blood vessels from the periosteum or medullary cavity enter here
Long Bone Structure
diaphysis
-shaft of the bone
Long Bone Structure
epiphysis
-part of a long bone that develops from a center of ossification distinct from the diaphysis
Long Bone Structure
epiphyseal plate
- area of hyaline cartilage between the diaphysis and epiphysis
- cartilage growth followed by endochondral ossification results in growth in bone length
Long Bone Structure
medullary cavity
-large cavity within the diaphysis
Long Bone Structure
periosteum
-double layered connective tissue membrane covering the outer surface of bone except where articular cartilage
Long Bone Structure
endosteum
-thin connective tissue membrane lining the inner cavities of bone
Long Bone Structure
perforating fibers
- bundles of collagen fibers
- strengthen the attachement of the tendons or ligaments to the bone
Long Bone Structure
articular cartilage
-thin layer of hyaline cartilage covering a bone where it forms a joint (articulation) with another bone
Intramembranous ossification
-takes place in connective tissue membranes
Endochondrial ossification
-takes place in cartilage
Zone of resting cartilage
-nearest the epiphysis and contains randomly arranged chondrocytes that do not divide rapidly
Zone of proliferation
- produce new cartilage through interstitial cartilage growth
- chondrocytes divide and form columns resembling stacks of plates or coins
Zone of hypertophy
- chondrocytes produced in the zone of proliferation mature and enlarge
- a maturation gradient exists in each column
Zone of calcification
-very thin and contains hypertrophied chondrocytes and calcified cartilage matrix
Parathyroid hormone (PTH)
- one hormone that maintains calcium homeostasis
- major regulator of blood Ca 2+ levels
- secreted from the parathyroid glands when blood Ca 2+ levels are too low
Calcitonin
- one hormone that maintains calcium homeostasis
- secreted from the thyroid gland when blood Ca 2+ levels are too high
