Exam 2: Cartilage Flashcards
Cartilage-forming cells are
chondroblasts
produce molecules of extracellular matrix and fibers embedded in matrix
Chondrocytes
chondroblasts that have become trapped in matrix they produced
Most common type of cartilage is
hyaline cartilage
Hyaline cartilage appears
glassy, whitish-blue
fine collagen fibrils are invisible with routine staining
Hyaline cartilage is located
in places where it maintains a lumen/open space (nose, larynx, trachea, bronchi)
At articular surfaces of bones (ribs with sternum as well as moveable joints)
At epiphyseal growth plates
Lacunae
bubbles within extracellular matrix that chondrocytes are trapped in
Isogenous groups
2-4 chondrocytes
come from same chondrocyte that has divided
Fibroblasts
cells that form fibers, derived from mesenchymal cells
form dense collagenous CT (fibrous outer layer of perichondrium)
Perichondrium
CT capsule that covers only hyaline and elastic cartilage
Layers of perichondrium
outer fibrous layer, inner cellular layer
Outer fibrous layer of perichondrium
dense collagenous connective tissues
type I collagen, fibroblasts, blood vessels, and nerves
Protective and supportive
Inner cellular layer of perichondrium
chondrogenic cells that differentiate into chondroblasts & form ECM
Cartilage grows on surface of existing cartilage - appositional growth
Allows for cartilage growth
Interstitial growth
Cartilage is added to the inside of tissue
Occurs only during early stages of cartilage formation, in articular cartilage, in epiphyseal plates (for lengthening of bone), and deep within cartilage
Appositional growth
Cartilage is added to outer surface of cartilage
Occurs in most cartilage, & throughout cartilage lifespan
What cartilage does not have perichondrium
Articular cartilage
Articular cartilage growth
Only interstitial growth - no appositional growth, because does not have perichondrium
Chondrogenic cells
arise from mesenchymal cells
Can differentiate into chondroblasts and osteoprogenitor cells
Chondroblasts
differentiate from mesenchymal cells and chondrogenic cells
Basophilic
form matrix and fibers of cartilage
Chondrocytes
have large nucleus, nucleolus, rER, GA, and glycogen in cytoplasm
Can go back to being chondroblasts
Trapped in lacuna within matrix - synthesize necessary molecules to maintain matrix
Hyaline cartilage contains mostly
type II collagen
Hyaluronan molecules
has many proteoglycan monomers attached to it
interwoven in network of collagen fibrils to give cartilage its resilience
How much of hyaline cartilage wet weight is water bound by proteoglycans
60-80%
Capsular (pericellular) matrix (hyaline cartilage)
intensely stained thin layer of matrix immediately around lacuna
highest concentration of sulfated proteoglycans
contains thin collagen fibers woven around each chondrocyte
Territorial matrix (hyaline cartilage)
lighter staining matrix surrounds isogenous group
lower concentration of sulfated proteoglycans than capsular matrix
interterritorial matrix (hyaline cartilage)
majority of matrix
fills space around territorial matrix
fibronectin
adhesive glycoprotein, assists chondroblasts and chondrocytes to adhere to ECM
What type of cartilage tends to calcify with age
Hyaline cartilage
Elastic cartilage contains
type II collagen and elastic fibers
Elastic cartilage is located in
pinna of ear, internal and external auditory tubes, epiglottis, and larynx
Fibrocartilage contains
type I collagen (acidophilic)
lacks a perichondrium
Fibrocartilage is located
where tough support and tensile strength is needed
Intervertebral discs, pubic symphysis, articular discs, menisci of knee joint, attached to bone
Osteoarthritis
breakdown of hyaline cartilage at joints
most prevalent in older individuals
