Cartilage & Bone Flashcards
cartilage
specialized form of fibrous CT
cartilage is avascular, meaning?
contains chondrocytes embedded in extracellular matrix; nutrients & waste pass through matrix
functions of cartilage
support soft tissues & guide development/growth of bones
3 types of cartilage?
hyaline, elastic, fibrocartilage
hyaline cartilage
location at articular ends of long bones, walls of respiratory system & ventral ends of ribs; in fetus until bone replaces it
hyaline cartilage matrix
amorphous ground substance with proteoglycan aggregates & chondronectin embedded type II collagen
proteoglycan aggregates
contains chondroitin & keratin sulfate & hyaluronic acid
chondronectin
glycoprotein in cartilage
territorial (capsular) matrix
area adjacent to chondrocytes thats poor in collagen but rick in glycosaminoglycans; very basophilic/metachromatic (PAS stain)
interterritorial (intercapsular) matrix
areas without staining
perichondrium
layer of dense irregular CT that surrounds hyaline cartilage except at articular surfaces
outer fibrous layer of perichondrium
contains type 1 collagen, fibroblasts, & blood vessels
inner cellular layer of perichondrium
contains chondrogenic cells which is a source of new cartilage cells
what provides the blood supply for avascular cartilage?
perichondrium
chondrocytes
mature cartilage cells embedded in lacunae in the matrix that make & maintain cartilage matrix
chondrocytes arise from?
chondrogenic cells into chondroblasts, which produce cartilage matrix
what cell is totally surrounded by matrix?
chondrocyte
isogenous groups
groups of 2-8 chondrocytes; when the cells divide they stay in the same lacunae
elastic cartilage
matrix contains network of elastic fibers; perichondrium similar to hyaline; yellowish color
where is elastic cartilage located?
flexible support areas such as external ear, eustachian tube, epiglottis, & larynx
elastic cartilage is _____ prone to degeneration than hyaline cartilage?
less
fibrocartilage
has no perichondrium, properties in between hyaline & dense CT
what is fibrocartilage made of?
alternating rows of fibroblast-derived chondrocytes & thick bundles of type 1 collagen fibers
where is fibrocartilage found?
where support & tensile strength are needed with hyaline cartilage, fibrous tissues; IV disks, articular disks, pubic symphysis, tendon/ligament insertions, knee joint menisci
what is bone?
specialized CT; calcified extracellular matrix with osteocytes embedded in matrix; main component of adult skeleton; supports tissues & organs; provides calcium reserve
bone matrix made of?
- inorganic (calcified) portion made of calcium, phosphate, bicarbonate, citrate, magnesium, potassium, & sodium; consists mostly of hydroxyapatite crystals;
- organic portion made of type 1 collagen; ground substance made of chondroitin sulfate & keratan sulfate
primary bone
immature bone formed in fetal development & bone repair with low mineral content
secondary bone
mature & lamellar bone; 2 types compact & spongy
compact bone
dense, outer portion of bone; organized with outer circumferential lamellae below periosteum & inner circumferential lamellae adjacent to marrow cavity; middle bone organized into osteons
spongy bone
meshwork of trabeculae in bone interior
osteons
haversian canals connected with Volkmann’s canals
bone periosteum
layer of noncalcified CT covering bone external surfaces except at synovial articulations;
what is bone periosteum made of?
outer fibrous dense collagenous layer & inner cellular (osteogenic) layer
what attaches periosteum to bone?
Sharpey’s fibers (type 1 collagen)
what does periosteum do?
distributes blood vessels to bone
endosteum
thin specialized CT that lines marrow cavities & is a source of osteoprogenitor cells & osteoblasts for bone growth & repair
osteoprogenitor cells
inner layer of periosteum & endosteal cells that line marrow cavity; flat/spindle shaped; can differentiate into osteoblasts
osteoblasts
secretes collagen, ground substance, & osteiod; regulates mineralization of bone; cuboidal in shape; metabolically active
osteoid
unmineralized bone
osteocytes
maintain bone matrix & reside in lacunae; communicates with other osteocytes/blasts with canaliculi & gap junctions
osteoclasts
multinucleated cell thats acidophilic; macrophage activity; actively resorb bone & release lysosomes into extracellular space
howship’s lacunae
depression in bone created by osteoclast for bone resorption by osteoclast
osteoporosis
decrease in bone mass due to decreased bone formation & increased bone resorption; occurs in old age (reduced secretion of growth hormone), immobile patients (lack of physical stress on bone), & postmenopausal women (diminished estrogen secretion)
osteomalacia
due to calcium deficiency in adults; deficient calcification of new bones & decalcification of old bones; severe in pregnancy due to loss of calcium to fetus
rickets
osteomalacia in children due to vitamin D deficiency & also calcium deficiency **deformation of bone spicules in epiphyseal plates —> slow bone growth & bone deformation
acromegaly
excess pituitary growth hormone in adults; very thick bones in limbs & facial skeleton
paget’s disease
osteitis deformans; bone remodeling doesn’t function properly —> abnormal bone, enlarged, brittle, prone to breakage
