Skeletal System Flashcards
Epiphyseal growth plate: successive mitotic division of chondrocytes => columns of chondrocytes
Zone of Proliferation
Exchange of waste & nutrients occurs in compact bone via _________
Haversian vessels
Chondroblasts are trapped in ______ in cartilage
lacunae
In endochondral ossification, ________ cells from periosteum migrate into medulla, along with growing blood vessels
Osteoprogenitor
Bones in limbs are _____ bones
long
type of bone that contains concentric layers with parallel collagen fibers
lamellar bone
Nonsynovial joints are joined by ____ tissue
dense CT
woven bone is transformed into ______ which helps stabilize & bind fracture together; Important to realign & stabilize, or “set” fracture before this happens
bony callous
Epiphyseal growth plate: capillaries of marrow cavity grow from diaphysis into growth plateChondrocytes degenerate; lacunae invaded by osteogenic cells
Zone of (Cartilage) Degeneration
2 types of lamellar bone
compact and cancellous
resting mesenchymal cells, reside in periosteum& endosteum; Can differentiate into osteoblasts & osteocytes
Osteoprogenitor cells
Immediately after fracture, ________ develops—pain, swelling, redness, & heat
inflammatory response
In endochondral ossification, complete ossification that occurs at maturity caused by the ________
closure of epiphysis
___ joint characterized by extensive movement surrounded by connective tissue capsule (joint capsule)•Lined by thin, discontinuous layer of cells, synovium; secretes a fluid; bathes articular surface•No basement membrane, so not a true epithelium; made of up to 4 cell layers of cells of mesenchymal origin
Synovial (diarthoses)
Concentric layers in lamellar bone are called
circumferential lamellae
Secondary function of bone and cartilage
protection, mineral storage, & hemopoiesis
evolutionarily derived from notochord in chordates; Formed of concentric layers of fibrocartilage
intervertebral discs
production of irregular new bone at edges of articular surfaces; limits range of motion
Osteophytes (bone spurs)
Hyaline cartilage is reinforced by what fibers?
Type 2 collagen
Epiphyses are composed of ______ bone and covered with ________
cancellous; hyaline articular cartilage
Specialized support tissue—extracellular components are mineralized for rigidity & strength
Bone
T/F: Cartilage is a vascular connective tissue
False; avascular
immature form of bone characterized by random orientation of collagen fibers
Woven bone
After formation of fibrous granulation tissue, Mesenchymal cells differentiate into ______, secrete matrix => progressive replacement of granulation tissue by ______ cartilage
chondroblasts; hyaline
T/F: Relative strength of bone and cartilage due to properties of ground substance & extracellular fibers
True
Joint that is limited movement; joined by dense connective tissue, lacks articular surface
Nonsynovial
Concentric bony lamellae laid down by successive layers of _____
osteoblasts
What hormone decreases blood calcium levels?
Calcitonin
Further mitotic divisions of cartilage lead to produce clusters of ________ cells in cartilage called
chondrocytes
Diaphysis is composed of ______ bone in the cortex and _____ bone in the medullary cavity
compact; cancellous
Inactive Haversian systems known as _________
interstitial systems
Cartilage formation begins with __________ cells that differentiate into chondroblasts
Stellate mesenchymal cells
What hormone stimulates osteoblast activity, inhibits osteoclasts leading to bone deposition?
Calcitonin
Bony remodeling is followed by invasion of the empty Haversian canal by ______
osteoblasts
joint that contains single layer of hyaline cartilage; Unites first rib with sternum; only one in human adult
Synchondrosis (1’ cartilage joint)
New cartilage forms within mass
Interstitial growth
After hyaline cartilage replaces granulation tissue, ______ and ______ from endosteum & periosteum at edge of wound grow inward, produce meshwork of ______ bone within provisional callous, deposit calcium salts in collagen matrix
osteoprogenitor cells & osteoblasts; woven
T/F: Haversian systems oriented perpendicular to long axis of bone
False; parallel
Epiphyseal growth plate: blood vessels from marrow cavity grow into cartilage mass;Osteogenic cells differentiate into osteoblasts, congregate on spicules of calcified cartilage matrix to form bony trabeculae
Zone of Ossification
in intramembranous ossification, _______ cells differentiate into______, produce osteoid, later mineralizes into bone
Mesenchymal; osteoblasts
(hormone) Oversecretion can lead to gigantism, or acromegaly; undersecretion leads to pituitary dwarfism
Somatotropin (pituitary growth hormone)`
T/F: Vit D necessary for synthesis of collagen;
False; Vit C
associated with consumption of large quantities of red wine, meat,asparagus, broccoli, cauliflower, Brussel’s sprouts (high in protein and nitrogen); some diuretics used to treat hyper tension can cause it too
gout
Endosteal/ periosteal surface depressions where osteoclasts are found
Howship’s lacunae (resorption bays)
Periosteum is a layer of ___________ tissue
fibrous connective tissue
Damage to annulus fibrosus causes nucleus pulposus to ______
herniate
____ part of skeletal system that is semi-rigid; derived from primitive mesenchymal cells; bone precursor
cartilage
Spongy & woven bone lack _______; present only in compact lamellar bone
Haversian system
After ~1 wk, ______ and _______ proliferate & grow into site
fibroblasts & capillaries
Rickets is caused by insufficient dietary _____ and/or ____
Ca and Vit D
Osteocytes connected by minute canals called ______ containing cytoplasmic extensions—Communicate with each other via ____________
canaliculi; gap junctions
Mineralized component of bone formed by inorganic salts, primarily ____ and _____, in form of ________
Ca and P; hydroxyapatite crystals
Osteoclasts function in Ca homeostasis by producing ______ &_______ that digest bone—secreted into ECS by ruffled border
organic acids; lysozymes
local, autoimmune rxn in joints => body produces Ab’s that attack joints => pain, damage to articular cartilage; thickening, inflammation of synovial membrane
Rheumatoid arthritis
In intramembranous ossification, ______ at periphery continue to divide, provide replacements
Osteoprogenitor cells
In endochondral ossification, At maturity, hormonal changes decreases _______ & cartilage plate replaced by ______
cartilage proliferation; bone
long bones, vertebrae, pelvis, & base of skull is made via _______ ossification
endochondral ossification
Outer periphery of cortical bone arranged in ______ are covered by __________
circumferential lamellae; dense connective tissue periosteum
Bone repair process usually takes ______ weeks
6-12 weeks
In endochondral ossification, 1’ center of ossification occurs in
mid-diaphysis
Shaft of the long bone is called the ______
diaphysis
Within center of each osteon is a Haversian canal containing ________
blood vessels & nerves
Intervertebral joints are a special type of _____
symphysis
Compact bone contains ______; produced via bony remodeling—removal of existing bone by osteoclasts and redeposition of new bone by osteoblasts
Haversian systems, also called osteons
T/F: Chondrocytes do not retain the ability to divide
False
large, multinucleate cells, probably derived from monocyte-Mφlineage; phagocytic; Actively involved in resorption & remodeling of bone; Usually found on endosteal/ periosteal surface in depressions, called Howship’s lacunae, or resorption bays
Osteoclasts
Inflammation of joints
arthritis
Type of cell in synovial joints that resemble macrophages
Type A (synoviocytes)
What kinds of cells are Osteoprogenitor cells?
resting mesenchymal cells
what are the 2 major forms of bone?
Woven and lamellar
part of Epiphyseal growth plate: hyaline cartilage with clusters of chondrocytes—no cell proliferation
Zone of Reserve Cartilage
fibroblasts & capillaries forms _______ tissue that becomes progressively more fibrous in chronic phase forming ________ tissue
Granulation tissue; Fibrous granulation tissue
Epiphyseal growth plate: chondrocytes greatly enlarge, contain large amounts of glycogen, become vacuolated & calcify
Zone of Hypertrophy (& Calcification)
In endochondral ossification, ________ in region of metaphysis remains “open”; Allows continuous longitudinal growth
Epiphyseal plate
Primary function of bone and cartilage
support & locomotion/ movement
direct replacement of mesenchyme by bone; no cartilage precursor
Intramembranous ossification
Which hormone stimulates osteoclast activity leading to bone resorption?
Parathyroid hormone
Bone has a high affinity for _____ and _______
heavy metals and radioactive isotopes
Consists of alternating layers of hyaline cartilage & dense connective tissue (contains Type I& Type II collagen); less cellular than either; Lacks perichondrium; found in intervertebral discs, some articular areas—
Fibrocartilage
parallel bundles of collagen fibers, extend from periosteum or Mm tendon & insert into superficial layer of bone; provide anchorage & support
Sharpey’s fibers
Most common glycoprotein in cartilage is _______; may have some anti-tumor properties
chondronectin
Matrix of hydrated cartilage, contains ~ 60-80% _____, bound to ________; accounts for its flexibility and incompressibility
H2O; proteoglycans
In skull, syndesmoses progressively replaced by bone to become _______
synostosis
GAGs of ground substance of bone consist mostly of
hyaluronic acid & chondroitin sulfate, as well as keratin sulfate
Mature, compact bone consists of ~ 70% ______ & 30% _______
inorganic salts; organic matrix
Dense fibrous tissue between bones
Syndesmosis
Epiphyseal growth plate: division ceases; chondrocytes ↑ in size
Zone of Maturation
Osteoblasts trapped within lacunae of osteoid, become _______
osteocytes
Ends of long bones are called
epiphysis
Treatment for osteoporosis includes
Oral Ca and Vit D; chondrotin, gulcosamine , and gelatin
In _____ ossification, Mesenchymal cells differentiate directly into osteoblasts, begin synthesizing osteoid at multiple sites, (multiple centers of ossification) within membrane—no cartilage precursor; Mineralization follows with subsequent fusion of adjacent centers of ossification
intramembranous
Tendency for all _____ cartilage to calcify with age, via deposition of calcium phosphate crystals within matrix; eventually replaced by bone
hyaline
In endochondral ossification, two secondary centers of ossification occur in _______; mineralization spreads across cartilage matrix
epiphyses
Thick cartilage contains blood vessels in _________
secondary cartilage canals
Fracture where there is bone broken in several pieces
Comminuted fracture
Progressive build-up of osteophytes, osteoarthritis or trauma can lead to _____
ankylosis
removal of existing bone by osteoclasts and redeposition of new bone by osteoblasts
bony remodeling
In endochondral ossification, After closure, growth plate persists as ______ in metaphysis, visible on X-rays
epiphyseal line
Resulting woven bone from endochondral ossification is extensively remodeled by _______ & ____ growth => lamellar bone
resorption; appostional
Synovial joints are made up of 4 layers of synovial cells of ________ origin
mesenchymal
Mature bone cells
Osteocytes
Fluid that bathes the articular surface of a synovial joint
synovial fluid
central core of viscous ground substance in the intervertebral disc
nucleus pulposus
roughly polygonal, mesenchymal cells derived from osteoprogenitor cells; Very basophilic due to synthesis of large amounts of protein & proteoglycans
Osteoblasts
Type of cartilage found in knee, mandible [TMJ], shoulder, sternum—ligaments, tendons, joint capsules, pubic symphysis)
Fibrocartilage
Vit C deficiency => ______; bone matrix not calcified•Can also lead to weakening of collagen in ligaments(especially periodontal ligament => loose teeth)•Breakdown of scars/ old wounds, which break open & bleed
scurvy
part of the long bone that is a Flared region between epiphysis & diaphysis; contains epiphyseal plate of long bones
metaphysis
_______ are responsible for calcification of matrix via secretion of matrix vesicles
Osteoblasts
Type of cartilage found in external ear, auditory & Eustacian canals, epiglottis, & larynx)
Elastic
What kind of fibers are found in Fibrocartilage?
Type 1 and 2 collagen
modified, folded plasma membrane, containing microvilli-like structures that secrete organic acids and lysozymes into ECS that are produced by osteoclasts that function in Ca homeostasis
Ruffled border
T/F: In endochondral ossification, Calcification of cartilage matrix inhibits diffusion of nutrients that leads to death of chondrocytes & spread of osteoblasts
True
replacement of articular cartilage with fibrovascular tissue
Pannus
Consists of several distinct zones in transition from cartilage to bone
Epiphyseal growth plate
What is the last long bone in humans to close around 18-20?
femur
Periosteum contains what cells?
fibroblasts and osteoprogenitor cells
In acute phase (first few days) ______ first to arrive, infiltrate hematoma, then (both phagocytic) to clean up site of injury
neutrophils; macrophages
Woven bone is later remodeled into _____ bone
lamellar
Treatment of scurvy
Fruits and Veg high in VIt C (citrus fruits like oranges, lemons, limes; also guavas)
Fracture where there is no break in skin
Simple or closed fracture
Internal marrow cavity of bones lined by
endosteum
Repair in cartilage is limited because repair requires blood flow; this results in production of _________ tissue
dense connective tissue
Type of cell in synovial joints resemble fibroblasts
Type B
replacement of cartilage precursor by bone
Endochondral ossification
Bony callous progressively remodelled into _______
mature lamellar bone
Clusters of chondrocytes that can be separated by extracellular matrix (territorial vs. interterritorial) are called
isogenous groups
pitting, erosion => pain, swelling, thickening of joint capsule; occurs following osteoarthritis
eburnation
Cartilage contains extracellular matrix of amorphous ground substance containing ________
collagen
Which hormone increases blood calcium and decreases renal excretion by kidneys?
Parathyroid hormone
Varying levels of _____ and ______ produce the different types of cartilage
matrix; fibers
Part of the long bone that contains red (hematopoietic) marrow or yellow (fatty) marrow
Medullary cavity
Peripheral zone of dense connective tissue containing fibroblasts, collagen, and immature chondroblasts; surrounds cartilage
Perichondrium
Thin continuous later of cells surrounding synovial joint
synovium
joint that contains two hyaline cartilage surfaces connected by fibrocartilage plate
Symphysis—(2’cartilage joint)
Outer margin of osteon is delimited by the ______
cement line
Osteoblasts mature into ______ within lacunae after matrix mineralizes
osteocytes
Fracture where there is damage to skin exposing bone
Compound or open fracture
Newer osteoporosis meds _____ bind phosphates in GI tract, minimize absorption•Possible side effects include mandibular necrosis
Fosamax
____ bone contains network of thin, bony trabeculae and open spaces
Cancellous
Contain alkaline phosphatase, bud off osteoblasts into matrix, causing precipitation of mineral salts
Matrix vesicles
Arise from stellate mesenchymal cells; grow and synthesize ground substance and fibrous extracellular matrix in cartilage
Chondroblasts
When osteoid mineralizes in endochondral ossification, it forms
periosteal cuff
Invasion of site by blood vessels in cartilage frequently results in death of _____ & formation of _______
chondrocytes; bone
Osteoblasts responsible for synthesis of extracellular matrix & collagen, collectively referred to as
osteoid
Perichondrium is made up of what cells?
Fibroblasts, collagen, and immature chondroblasts
GAGs in cartilage include
hyaluronic acid, (non-sulfated), chondroitin sulfate & heparin sulfate
Blood fills fracture site leads to a ______
hematoma
More mature chondrocytes present at ______________
center of cartilage pass
In endochondral ossification, Precursor of long bone formed of
hyaline cartilage
deposit of urates & uric acid crystals in joints (especially fingers & toes);Extremely painful
Gout
bone matrix doesn’t calcify normally in children during growth => soft, deformed bones; can be permanent
Rickets
Exchange of metabolites occurs via diffusion through __________ which limits the thickness of mature cartilage
ground substance
External surface of bone covered by ______—layer of fibrous connective tissue
periosteum
progressive degeneration & loss of articular cartilage
Osteoarthritis
in adults, insufficient Ca & Vit D can lead to _____ (failure of mineralization) => softening of bone
osteomalacia
What hormones stimulates growth especially epiphyseal cartilage and bone; decreases blood Ca?
Somatotropin (pituitary growth hormone)
In intramembranous ossification, Bone produced is______ bone—later remodeled by osteoclasts & osteoblasts to form ______ bone
woven; compact
New cartilage forms at surface of pre-existing cartilage; more common
appositional growth
The _____ cartilage is the precursor for bone in most of the skeleton
Hyaline
______ Forms annulus fibrosus around central core of viscous ground substance, nucleus pulposus
concentric layers of fibrocartilage
bony fusion of joint with loss of mobility
ankylosis
In appositional growth, new chondrocytes are derived mesenchymal cells of the _________; differentiate first into chondroblasts
inner perichondrium
Osteoblasts become trapped in ______ in osteoid matrix & mature into _______
lacunae; osteocytes
vault of skull is made via _____ ossification
intramembranous ossification
Histologically similar to hyaline cartilage (contains Type IIcollagen), with addition of large #’s of elastic fibers in extracellular matrix
Elastic cartilage
loss of bone mass•Resorption by osteoclasts exceeds deposition by osteoblasts•Common problem in post-menopausal women, possibly due to ↓ estrogen levels
Osteoporosis
Bone growth is controlled by what hormones?
growth hormone, thyroid hormone, & sex hormones
Precursor for bone in most of skeleton; Characterized by small aggregates of chondrocytes in amorphous matrix of ground substance, reinforced with Type II collagen fibers
Hyaline cartilage
Elastic cartilage contains what fibers?
Type 2 collagen and elastic fibers
Cartilage Found in articular surfaces, growth plates, nasal septum, costal cartilage (ribs), tracheal & bronchial rings;
Hyaline
When fracture site completely bridged by woven bone, it leads to ______
bony union
Longitudinal Haversian canals are connected by ________
transverse Volkmann’s canals
_______ cells and ______ secrete osteoid
Osteoprogenitor; osteoblasts
