CTO Quiz 2: Cartilage and Bone Flashcards
Functions of Cartilage
1) Structural support of soft tissues
2) Shock absorption between joints
3) Reduce friction between joint surfaces
4) Role of growth and development in long bone
Types of Connective Tissue
1) Connective Tissue Proper Loose, Dense (Regular and Irregular) 2) Connective Tissues with Special Properties Adipose, Elastic, Hematopoietic, Mucous 3) Supporting Connective Tissues Cartilage, Bone
Components of Cartilage (cells)
chondroblasts–>chondrocytes
Types of Cartilage
1) Hyaline
2) Elastic
3) Fibrocartilage
Elastic Cartilage
Type 2 collagen, elastic fibers
flexible
yellow- due to elastin
Hyaline Cartilage
Most common Type 2 collagen Embryo skeleton Ephiphyseal plates of long bones holds a lot of water
Hyaline Locations
Articular surfaces of moveable joints (**articular cartilage is a type of hyaline) Ends of ribs Respiratory passages Nose Larynx
Locations of Elastic Cartilage
ear
Eustachian tube
epiglottis of larynx
Fibrocartilage
Type 1 collagen
flexible strength
dense CT
resists tension and shearing forces
Fibrocartilage Locations
Intervertebral and articular discs
menisci of knee
pubic symphysis
Formation of Cartilage
mesenchymal cells (with transcription factor SOX-9)–> chondroblasts–> produce matrix–> chondrocytes (inside lacuna)
Isogenous Nests
chondrocytes undergo mitosis- when multiple daughter cells are in one lacuna (eventually get separated by matrix)
Perichondrium
dense CT outer layer of most cartilage (except articular and fibrocartilage)
source of nutrition
inner layers contain chondrogenic cells- can become chondroblasts
Interstitial Growth
new cartilage added in middle
Appositional growth
new cartilage added at edge
fibroblast–>chondrogenic cells–>chondroblast–>chondrocyte (inner perichondrium differentiation)
Hyaline Articular Cartilage
no perichondrium
cannot repair easily
ex- shoulder
Osteoarthritis
breakdown and loss of cartilage on articular joint surfaces
bone spurs
risk factors- obesity, women, older than 45, joint injury, heredity
treatment- pain and anti-inflammatory meds, exercise, weight loss, joint replacement
Components of Bone (cells)
osteoblasts, osteocytes, osteoclasts
Epiphysis
expanded end with articular cartilage
Diaphysis
shaft of long bone
medullary cavity- osteoclastic activity
Epiphyseal Plate
area where growth occurs in young bones
Periosteum
dense connective tissue layer covering bone
Sharpey’s Fibers
collagen fibers that extend into the bone and are continuous with the collagen fibers of the bone matrix function to anchor periosteum to the bone
Periosteum
dense connective tissue layer covering bone
inner fibrous outter layer containing osteoprogenitor cells
Endosteum
thinner layer on the inside of bone
contains cells that can proliferate as osteoblasts
Osteoprogenitor Cells
stem cells found on external and internal surfaces of bone (perosteum and endosteum)
have capacity to differentiate into osteoblasts
active during bone and growth repair
Osteoblasts
found on the surfaces of bone
produce and secrete organic components of bone matrix (osteoid)
active (round) or inactive (flat)
become osteocytes when surrounded by matrix
Osteocytes
are completely surrounded by matrix within lacunae
function to maintain the bone matrix
have cytoplasmic processes within canaliculi that serve as communication links with other cells via gab junctions
function to maintain bone matrix- bone grows from appositional growth, not interstitial (because calcified)
Osteoclasts
large motile multinucleated cells derived from blood monocytes
responsible for bone resorption
develop from hematopoietic cells (fusion of monocytes)
Resorption of Bone
osteoclasts- multi nuceated
ruffled border- region that contains infoldings of the plasma membrane and is directly involved in resorption
clear zone- surrounds periphery of ruffled border and is where the osteoclast firmly adheres to bone matrix- is devoid of organelles, rich in actin filaments
hydrolytic enzymes (including acid phosphataseare released from lysosome into the clefts between the processes of the ruffled border
degraded minerals and organic components are endocytosed and delivered to nearby capillaries
Trabeculea
bars and spicules of bone
in spongy bone there are gaps between trabeculae filled with bone marrow
Immature Bone
first bone that is formed in fetus or during repair
many osteocytes, low mineral content, irregular array of collagen fibers
Mature Bone
secondary, lamellar
majority of adult bone
collagen fibers are arranged in lamellae that are either parallel or circumferentially arranged
spongy bone typically parallel, compact typically circular
Osteon (Haversian System)
lamellae are arranged in circular pattern around a central canal containing artery and vein
lamellae are layed down by concetnric layers of osteocytes
angles of fibers to add strenght to matrix
lacunae containing osteocytes are found between layers
canaliculi connect adjacent lacuna
Volkman’s Canals
contain blood vessels of adjacent Haversian systems to connect them
organized just below endosteum and periosteum
connect haversian cannals with periosteum and bone marrow
Interstitial Lamellae
oldest part of bone
fill up spaces between osteons and circumferential lamellae
remnants of prior osteons that were partially removed by osteoclasts
Cicumferential Lamellae
organization of lamellar bone at outter and inner aspect of bone- just beneath periosteum and endosteum
parallel to bone surface and surround entire bone in circumferential manner
Components of Cartilage (fibers)
collagen (1 and 2), elastic
Components of Cartilage (ground substance)
glycosaminoclycans- hyaluronic acid, chondroitin sulfate
proteoglycans- chondronectin, stain darkly
Components of Bone (fibers)
type 1 collagen
Components of Bone (ground substance)
proteoglycans
glycoproteins- osteonectin, osteocalcin
calicified extracelllar matrix
General Functions of Bone
provides supportive framework for softer tissues of body
serves as site of attachment for muscles to produce movement (site of attachment for ligaments and muscles)
protects vital organs
bone marrow-site of hematopoiesis
provides reservoir of calcium and phosphate
Structures of Bones
bone tissue hematopoietic tissue adipose tissue cartilage blood vessels nerves
Metaphysis
flared part of shaft of long bone
Articular Cartilage
top of bone, no periostium so no appositional growth, can do some interstitial growth
Short Bone
ex carpias of wrist
Flat Bone
ex parietal bone
Irregular Bones
ex vertebrae
Microscopic Organization of Bone
immature- can have irregular matrix, primary bone is bone first formed in fetus or during repair
many osteocytes, low mineral content, irregular array of collagen fibers
mature (aka secondary or lamellar bone)- highly organized regular matrix, majority of adult bone, uses gap junctions to pass nutrients back and forth,
collagen fibers arranged in lamella that are either parallel or circumfrentially arranged
spongy (cancelous) bone typically parallel, compact bone typically circular (osteons)
Macroscopic Organization of Bone
compact- very dense, strong, high percentage of weight, low percentage of space
spongy- spong like (trabaculae/bars/spinacules of bone filled with marrow), not as strong, low weight, high percentage of space
Haversian Canal
center of osteon
contains vessels (artery and vein) and nerves
location of nutrient transport
Osteogenesis
formation of one
occurs in embryo to form bony skeleton
occurs during adolescence for growth
occurs during adulthood for remodeling and repair
Bone Formation
molecular signals after genetic expression at appropriate times–> bone formation
2 types- both form primary bone through trabecular network (spicules first)- intramembranous ossification and endochondral ossification
