CARTILAGE

Cartilage

Tough, durable form of supporting connective tissue, characterized by an extracellular matrix with high concentrations of GAGs and proteoglycans, interacting with collagen and elastic fiber

Cartilage

Provides cushioning and sliding regions within skeletal joints and facilitates bone movements

Chondrocytes

Cartilage consists of cells called what?

Extracellular matrix

Where are chondrocytes embedded?

Chondrocytes

What cells are located in the ECM of the cartilage?

Chondrocytes

Synthesize and maintain all ECM components and are located in matrix cavities called lacunae

Lacunae

Chondrocytes are located where?

Type ii collagen, hyaluronan, proteoglycans

Physical properties of cartilage depend on electrostatic bonds

Vascular supplies

All types of cartilage lack what?

Diffusion from capillaries

Chondrocytes receive nutrients by what?

Low metabolic activity

Chondrocytes exhibit what?

No

Do cartilage have nerves?

Perichondrium

Sheath of dense connective tissue that surrounds cartilage in most places, forming an interface between the cartilage and the tissues supported by the cartilage

Perichondrium

Harbors the blood supply serving the cartilage and a small neural component

Articular cartilage

Covers the ends of bones in movable joints and which erodes in the course of arthritic degeneration

Articular cartilage

What cartilage lacks perichondrium?

Synovial fluid

Articular cartilage is sustained by diffusion from what?

Hyaline cartilage

Most common cartilage

Hyaline cartilage

Homogenous and semitransparent in the fresh state

Adult hyaline cartilage

Located in the articular surfaces of movable joints, in the walls of larger respiratory passages (nose, larynx, trachea, bronchi), in the ventral ends of ribs, where they articulate with the sternum, and in the epiphyseal plates of long bones, where it makes possible longitudinal bone growth

Longitudinal bone

Adult hyaline cartilage allows the growth of what bone?

Embryo hyaline cartilage

Forms the temporary skeleton that is gradually replaced by bone

hyaline cartilage

Provides smooth, low-friction surfaces

in joints; structural support for

respiratory tract

Elastic cartilage

Provides flexible shape and support

of soft tissues

Fibrocartilage

Provides cushioning, tensile

strength, and resistance to

tearing and compression

Hyaline cartilage

Many components of upper respiratory

tract; articular ends and epiphyseal

plates of long bones; fetal skeleton

Elastic cartilage

External ear, external acoustic

meatus, auditory tube; epiglottis and

certain other laryngeal cartilages

Fibrocartilage

Intervertebral discs, pubic

symphysis, meniscus, and certain

other joints; insertions of tendons

Osteoarthritis

Gradual loss or changed physical

properties of the hyaline cartilage that lines the articular ends of bones in joints

40%

How much collagen is in hyaline cartilage?

Proteoglycans

Make the hyaline cartilage matrix generally basophilic and the thin collagen fibrils are barely discernible

Type ii collagen

Most collagen in hyaline is what type?

Aggrecan

Most abundant proteoglycan of hyaline cartilage.

Chondronectin

Structural multiadhesive glycoprotein

Chondronectin

Binds specifically to GAGs, collagen, and integrins, mediating the adherence of chondrocytes to the ECM

Chondroblasts

Have an elliptic shape, with the long axes parallel

to the surface

Isogenous aggregates

Clusters of 2-8 cartilage cells housed within a single lacuna, originating from the mitosis of a single parent chondroblast in hyaline and elastic cartilage

Low-oxygen tension

Chondrocytes breath under what?

Anaerobic glycolysis

Hyaline cartilage cells metabolize glucose mainly by what?

Calcification

Hyaline cartilage is susceptible to what?

Somatotropin (growth hormone)

Major regulator of hyaline cartilage growth

Chondrosarcoma

Malignant tumors of cartilage

Chondroma

Benign tumors of cartilage

Collagen type I fiber and fibroblast

The outer region of the perichondrium consists largely of what?

Mesenchymal stem cells

Inner layer adjoining the cartilage matrix contains what?

Elastic cartilage

Similar to hyaline cartilage, except that it contains an abundant network of elastic fibers and collagen type II fibrils

Yellowish color

What color is elastic cartilage?

Fibrocartilage

Mingling of hyaline cartilage and dense connective tissue

Chondrocytes of fibrocartilage

Occur singly and often in aligned isogenous aggregates, producing type II collagen and other ECM components

Chondrogenesis

Process where mesenchyme forms cartilage

Chondroblasts

Cartilage cells during the period of rapid proliferation

Chondrocytes

Cartilage cells after the period of rapid proliferation

Center outward

Cartilage differentiation takes place primarily from what direction?

Chondrocytes

Central cells have the characteristics of what?

Chondroblasts

Periphery cells have the characteristics of what?

Interstitial growth

The expansion of tissue from within, driven by cell division (hyperplasia) and increased matrix production by existing chondrocytes (cartilage cells) in their lacunae

Appositional growth

Increase in diameter or thickness of bones and cartilage by adding new tissue to the outer surface, rather than in length

Interstitial growth

Important in increasing the length of these structures