Lab Quiz 3 Material (02/20/2025) + Ch. 7 Cartilage (E3) Flashcards by Jordan Cole

What are the 2 key components of cartilage?

1) Chondrocytes
2) Highly specialized extracellular matrix (ECM)

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Is cartilage a vascular or an avascular tissue?

Avascular

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List 3 terms that best describe the extracellular matrix in cartilage.

NOTE: These terms are mentioned in the text.

1) Solid
2) Firm
3) Pliable

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Why is the composition of the extracellular matrix so crucial to the survival of chondrocytes?

Cartilage is avascular, so there is no direct blood supply for chondrocytes

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Since cartilage is avascular, how do chondrocytes survive?

NOTE: The answer has something to do with the ratio of glycosaminoglycans and type II collagen fibers.

There is a large ratio of glycosaminoglycans (GAGs) to type II collagen fibers that permits diffusion of substances between blood vessels from the surrounding connective tissue and the chondrocytes within the ECM

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This type of cartilage is characterized by matrix-containing type II collagen fibers, GAGs, proteoglycans, and multi-adhesive glycoproteins.

What is hyaline cartilage?

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Elastic fibers and elastic lamellae characterize this type of cartilage in addition to the matrix material of hyaline cartilage.

What is elastic cartilage?

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This type of cartilage is characterized by abundant type I collagen fibers and the matrix material of hyaline cartilage.

What is fibrocartilage?

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Name this type of cartilage based on the following locations:

Fetal skeletal tissue, epiphyseal plates, articular surface of synovial joints, costal cartilages of rib cage, cartilages of nasal cavity, larynx (thyroid, cricoid, and arytenoids), rings of trachea, and plates in bronchi.

Hyaline

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List 4 functions of hyaline cartilage.

1) Resists compression

2) Cushions and provides a low-friction surface for joints

3) Provides structural support in the respiratory system

4) Forms foundation for fetal skeleton development, endochondral bone formation, and bone growth

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Name this type of cartilage based on the following locations:

Pinna of external ear, external acoustic meatus, auditory (Eustachian) tube, and cartilages of larynx (epiglottis, corniculate, and cuneiform cartilages).

Elastic

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What is the function of elastic cartilage?

To provide flexible support for soft tissues

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Name this type of cartilage based on the following locations:

Intervertebral discs, pubic symphysis, articular discs (sternoclavicular and temporomandibular joints), menisci (knee joint), triangular fibrocartilage complex (wrist joint), and insertion of tendons.

Fibrocartilage

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What is the function of fibrocartilage?

To resist deformation under stress

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Throughout the hyaline cartilage matrix are spaces called…

Lacunae

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Located within the lacunae are these cells.

What are chondrocytes?

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Does hyaline cartilage show abrasive wear over time? If not, are there exceptions that show signs of wear?

Generally speaking, NO. Despite its limited capacity for repair under normal circumstances, there’s no evidence of abrasive wear over a lifetime. HOWEVER, articular cartilage, in particular, wears down with age in many people

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What are the 3 classes of molecules that exist in the hyaline cartilage matrix?

1) Collagen molecules
2) Proteoglycans
3) Multi-adhesive glycoproteins

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This collagen molecule constitutes the bulk of the matrix fibrils.

What is type II collagen?

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This collagen molecule facilitates fibril interaction with the matrix proteoglycan molecules.

What is type IX collagen?

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This collagen molecule regulates the fibril size.

What is type XI collagen?

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This collagen molecule organizes the collagen fibrils into a 3D hexagonal lattice crucial to its successful mechanical function.

What is type X collagen?

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This collagen molecule is found mainly at the periphery of the chondrocytes, where it helps to attach these cells to the matrix framework.

What is type VI collagen?

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Types II, VI, IX, X, and XI are found in significant amounts only in the cartilage matrix. As such, they are referred to by this name.

What are cartilage-specific collagen molecules?

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List the 3 glycosaminoglycans (GAGs) found within the ground substance of hyaline cartilage.

1) Hyaluronan 2) Chondroitin sulfate 3) Keratin sulfate

In loose connective tissue matrix, the chondroitin and keratan sulfate of the cartilage matrix are joined to a {...} protein to form a {...} monomer.

1) Core 2) Proteoglycan

The most important proteoglycan monomer in hyaline cartilage is {...}, also known as cartilage-specific proteoglycan core protein, which in humans is encoded by the ACAN gene.

Aggrecan

How do proteoglycan aggregates form?

When linear hyaluronan molecules are associated with/ many aggrecan molecules, which are bound to hyaluronan by link proteins at the N-terminus

Also known as noncollagenous and non-proteoglycan-linked glycoproteins, these glycoproteins influence interactions between the chondrocytes and the matrix molecules.

What are multiadhesive glycoproteins?

Give 3 examples of multiadhesive glycoproteins with a small description of what each does.

1) Anchorin CII - collagen receptor on chondrocytes 2) Tenascin - anchor chondrocytes to the matrix 3) Fibronectin - same function as tenascin

These matrix aggregates are bound tightly by the intercellular water within hyaline cartilage and are responsible for imparting resilience to the cartilage.

What are aggrecan-hyaluronan aggregates?

Briefly describe the concept of internal remodeling.

It is a continuous process by which cells replace matrix molecules lost through degradation

Within hyaline cartilage, there are 2 ways that chondrocytes are distributed. What are these ways?

1) Singularly 2) Isogenous groups (clusters)

This type of cartilage matrix is a ring of more densely staining matrix located immediately around the chondrocyte. It contains the highest concentration of sulfated proteoglycans, hyaluronan, biglycans, and several multiadhesive glycoproteins.

What is capsular (pericellular) matrix?

This type of cartilage matrix is a region that is more removed from the immediate vicinity of the chondrocytes. It surrounds ISOGENOUS GROUPS and has a lower concentration of sulfated proteoglycans and stains less intensely than the capsular matrix.

What is territorial matrix?

This type of cartilage matrix is the region that surrounds the territorial matrix and occupies the space between groups of chondrocytes.

What is the interterritorial matrix?

In early fetal development, hyaline cartilage is the precursor of bones that develop by this process.

What is endochondral ossification?

During the developmental process, in which most of the cartilage is replaced by bone, residual cartilage at the proximal and distal ends of the bone serves as these growth sites.

What are epiphyseal growth plates?

A dense, irregular connective tissue composed of cells that are indistinguishable from fibroblasts.

What is perichondrium?

Hyaline cartilage that covers the articular surfaces of movable joints is deemed this.

What is articular cartilage?

List the 4 zones of articular cartilage.

1) Superficial (tangential) zone 2) Intermediate (transitional) zone 3) Deep (radial) zone 4) Calcified zone

This articular cartilage zone is a pressure-resistant region closest to the articular surface. It contains numerous elongated and flattened chondrocytes surrounded by a condensation of type II collagen fibrils arranged in fascicles parallel to the free surface.

What is superficial?

This articular cartilage zone lies below the superficial zone and contains round chondrocytes randomly distributed within the matrix. Collagen fibrils are less organized and are arranged in a somewhat oblique orientation to the surface.

What is intermediate?

This articular cartilage zone is characterized by small, round chondrocytes arranged in short columns perpendicular to the free surface of the cartilage. The collagen fibrils are positioned between columns parallel to the long axis of the bone.

What is deep?

This articular cartilage zone is characterized by a calcified matrix with the presence of small chondrocytes.

What is calcified?

The calcified zone is separated from the deep (radial) zone by a smooth, undulating, heavily calcified line called this.

What is the tidemark, or chondro-osseus junction?

The calcified zone rests upon this layer of bone just below the articular cartilage.

What is subchondral bone?

This line is the junction between the calcified zone and the subchondral bone.

What is the cement line?

What happens within the subchondral bone in response to joint injury?

It triggers active calcification to form a thicker subchondral bone plate

What 2 components make up the elastic cartilage matrix?

1) A dense network of branching and anastomosing (connecting) elastic fibers 2) Interconnecting sheets of elastic material

A combination of dense regular connective tissue and hyaline cartilage.

What is fibrocartilage?

What 2 types of collagen will you find in the extracellular matrix of fibrocartilage?

1) Type I (characteristic of connective tissue matrix) 2) Type II collagen (characteristic of hyaline cartilage)

A proteoglycan monomer secreted by fibroblasts found in more significant amounts in the ECM of fibrocartilage than aggreacan.

What is versican?

The proteolytic degradation of proteoglycan aggregates present in the extracellular matrix of fibrocartilage can result in this histopathology.

What is intervertebral disc degeneration?

In fibrocartilage, you'll find a small number of {...} (cells) with elongated nuclei and numerous {...} (cells) with dark, round nuclei.

1) Fibroblasts 2) Chondrocytes

The chondrocytes of fibrocartilage are contained within {...} with very little cartilage {...} surrounding them.

1) Lacunae 2) Matrix

In Figure 7.13 (the photomicrograph of fibrocartilage), what stain technique is used to turn the COLLAGEN FIBERS GREEN?

Gomori trichrome prep

What does the presence of chondrocytes in an isogenous group indicate?

That the cells have recently divided

What are the 2 layers of actively growing perichondrium?

1) Inner cellular layer 2) Outer fibrous layer

In addition to containing the normal components of hyaline cartilage matrix, {...} cartilage matrix also contains a dense network of branching and anastomosing elastic fibers and interconnecting sheets of elastic material.

Elastic

This type of cartilage is a combination of dense regular connective tissue and hyaline cartilage.

What is fibrocartilage?

In terms of perichondrium, how does fibrocartilage differ from hyaline and elastic cartilage?

Fibrocartilage has no surrounding perichondrium

What 2 types of collagen will you find in significant quantities within the ECM of fibrocartilage?

Types I & II

In addition, the extracellular matrix of fibrocartilage contains larger amounts of {...} (a proteoglycan monomer secreted by fibroblasts) than aggrecan (produced by chondrocytes).

Versican

The presence of {...} in the ECM gives elastic cartilage great flexibility to endure repeated bending.

Elastin

Does elastic cartilage calcify during the aging process?

This bone disease is associated with proteolytic degradation of proteoglycan aggregates present within the extracellular matrix of the fibrocartilage.

What is IV disc degeneration?

The process of cartilage development.

What is chondrogenesis?

The site of hyaline cartilage formation is recognized initially by an aggregate of mesenchymal or ectomesenchymal cells known as this.

What is a chondrogenic nodule?

Expression of transcription factor {...} triggers differentiation of these cells into {...}, which then secrete cartilage matrix (expression of SOX-9 coincides with secretion of type II collagen).

1) SOX-9 2) Chondroblasts

When are chondroblasts officially considered chondrocytes?

When they are completely surrounded by matrix material

Mutations of the {...} gene (ACAN) in humans cause early growth cessation of epiphyseal cartilages in long bones (despite normally timed puberty).

Aggrecan

Mutations in the aggrecan gene (ACAN) is linked to this disease, which is a skeletal disorder characterized by severe short stature (dwarfism) with advanced bone maturation and early onset of osteoarthritis.

What is spondyloepimetaphyseal dysplasia?

The growth process that forms new cartilage at the surface of existing cartilage.

What is appositional growth?

The growth process that forms new cartilage within an existing cartilage mass.

What is interstitial growth?

Slow-growing malignant tumors characterized by secretion of cartilage matrix.

What are chondrosarcomas?

What percent of primary cone tumors in the U.S. are diagnosed as chondrosarcomas?

3.6%

In which portion of the skeleton will you mostly find chondrosarcomas? Axial or appendicular?

Axial

True or False: Cartilage has a limited ability for repair.

True

Under what conditions can some cartilage repair be done? What cells allow for this?

Only in defects involving the perichondrium; pluripotent progenitor cells in the perichondrium allow for this

At the molecular level, cartilage repair is a tentative balance between deposition of type {...} collagen in the form of scar tissue and repair by expression of {...} collagens.

1) I 2) Cartilage-specific

Hyaline cartilage is prone to {...}, a process in which calcium phosphate crystals become embedded in the cartilage matrix.

Calcification

As hyaline cartilage calcifies, it is replaced by...

Bone

List 3 situations in which hyaline cartilage matrix calcification occurs.

1) Articular cartilage in contact w/ bone tissue in growing, adult bone (but not on the articular surface) calcifies 2) Endochondral ossification 3) Aging

Many investigators believe the process of cartilage removal involves a specific cell type designated as a {...}. This cell is described as resembling an {...} in both morphology and lytic function.

1) Chondroclast 2) Osteoclast

Chondroblasts have been observed on both calcified and non-calcified articular cartilage erosions in this type of arthritis.

What is rheumatoid arthritis?

The repair of cartilage mostly involves the production of this type of connective tissue.

What is dense connective tissue?