specialized connective tissue cartilage and bone

cartilage is a

specialized kind of connective tissue

chondroblasts

active forming cells

chondrocytes

when chondroblasts are fully formed and are placed in a gel matrix

chondrocytes pt 2

cells that have finished their job and are currently resting

what predominates

ECM (extracellular matrix)

where are cells enclosed (what are those cavities called)

lacunae

lacunae

sac like structures containing cells

what doesn’t cartilage contain

no blood vessels and no nerve supply of its own

cartilage is capable of?

rapid growth and is very ideal for embryo

what is first laid down that is then replaced by bone?

axial and appendicular skeleton as cartilage model

where is growth restricted

in postnatal life

perichondrium

joint cartilage is covered by this dense connective tissue

what the three kinds of cartilages

• hyaline

• elastic

• fibrocartilage

hyaline cartilage

the most common that is modified into two other types

location of hyaline cartilage

• end of ribs

• tracheal rings

• larynx

• joint surfaces

what is the formation of hyaline called

chondrogenesis

mesenchymal cells secrete?

hyaline matrix and collagen

as matrix increases cells become

isolated and enclosed in lacunae and eventually become chondrocytes

the growth of cartilage occurs in two different mechanisms?

• interstitial growth

• appositional growth

what is interstitial growth

cells in matrix that mitotically divide and increase in number

what is appositional growth

periochondrium bilayered

inner chondrogenic

is able to produce cartilage

• chondroblast—> cartilage

outer nonchrondrogenic

does not form cartilage

chondrocytes are considered what kind of cells

mature cartilage cells

chondrocytes properties

• irregular cells

• in lacunae

• some cells will cluster (isogenous cells)

• actively producing energy

• rich in ER and GC

• some lipid droplets in cytoplasm

isogenous cells

chondrocyte cells that cluster

the hyaline cartilage matrix is

homogenous (smooth) and can be differentiated into territorial and inter-territorial matrix

• has small collagenous fibrils

• matrix is basophillic ground substance and pas+

• have chondroitin sulfate and keratan sulfate

the cartilage matrix has what type of cartilage

type II collagen

hyaline undergoes what kind of change?

regressive

this regressive change leads to what?

calcification

calcification leads to ?

bone formation

so hyaline cartilage undergoes ____ change called _____ that lead to bone ______

regressive, calcification, formation

bone formation is called

endochondral ossicfication

in endochondral ossification chondrocytes undergo changes and form?

successive zone in the metaphysis

what are these successive zones?

1. Reserve zone

2. Proliferative zone

3. Zone of hypertrophy and maturation

4. Zone of provisional calcification

5. The ossification zone

reserve zone?

the resting cartilage

• quiesent cartilage

• nothing happens here

proliferative zone

rapid mitosis under the influence of growth hormone

zone of hypertrophy and maturation

mitosis stops and cells become larger

• glycogen

• lipid

• alkaline phosphatase

zone of provisional calcification

ready to absorb calcium

ossification zone

the osteoblasts secrete a covering (osteoid)