Cartilage Flashcards
_____: immature cartilage cells. Secrete extracellular matrix, but not yet imprisoned in a lacuna
chondroblasts
____: mature cartilage cells embedded in a matrix
chondrocytes
chondrocytes reside in small spaces within the matrix called _____
lacunae
organelle systems in cytoplasm are typical of cells that ______
secrete proteins
_____: a specialized connective tissue composed of cells and fibrous macromolecules embedded in a ground substance that provides support to the body and serves as a model or template for the formation of bones
cartilage
What is the role of cartilage in prenatal life?
Cartilage participates in the embryonic/fetal skeletal development, as a model or template for the bones of the appendicular and axial skeleton
the nutrition of cartilage cells is dependent on _______
diffusion of nutrients from blood capillaries in perichondrium and/or adjacent tissues
____ is composed of intercellular substance (ground substance) and fibrils
matrix
3 types of glycosaminoglycans that make up the intracellular substance of the matrix
- chondroitin sulfate
- keratan sulfate
- hyaluronic acid
______ and _____ join to form proteoglycan monomers.
chondroitin sulfate
keratan sulfate
2 types of fibrils
- collagen
- elastin fibers
_____ provides tensile strength and durability to cartilage
collagen
_____ fibrils are generally arranged in a 3D felt-like pattern
collagen fibrils
3 types of cartilage
- hyaline cartilage
- elastic cartilage
- fibrocartilage
____ is the most common form of cartilage in the body
hyaline cartilage
the matrix of hyaline cartilage is rich in _______ fibers
type II collagen fibers
the matrix of ______ cartilage is rich in type II collagen fibers
hyaline
____ cartilage is present in both the fetus and the adult
hyaline
two layers of the perichondrium
- fibrous layer
- chondrogenic layer
the more peripheral layer of the perichondrium is the _____ layer, the inner layer is the _____ layer
- fibrous
- chondrogenic
the _____ and the ______ lack a perichondrium
- articular cartilage
- epiphyseal growth plate (physis)
the _____ layer of the perichondrium generates new chondroblasts
chondrogenic layer
within the growth plate, type II collagen is synthesized primarily by _____ chondrocytes
proliferating
within the growth plate, type X collagen is synthesized by _____ chondrocytes
hypertrophic
in hyaline cartilage, _____ provide tensile strength and shape to cartilage while _____ absorb compressive forces
- collagen fibers
- proteoglycans
chondrocytes also produce _____, a fibronectin-like connecting glycoprotein that specifically binds collagen fibers and proteoglycans to chondrocytes
chondronectin
the matrix immediately surrounding the lacunae (newest formed) is more basophilic than more peripherally placed matrix and is referred to as ______, the outlying matrix is referred to as _______
- territorial matrix
- interterritorial matrix
the firm gel-like quality of cartilage is due to the ________________
high concentration of very large proteoglycan aggregates
the 2 principal glycosaminoglycans in hyaline cartilage
- chondroitin sulfate
- keratan sulfate
the compressive strength of cartilage is largely due to its _________ (____-___%)
high water content (70-80%)
How do water molecules become immobilized between the GAG side chains in cartilage?
the negatively charged carboxyl and sulfate groups (COO- and SO4 -2 groups) of the glycosaminoglycan molecules attract sodium ions and immobilize water molecules.
metabolites must pass from capillaries to chondrocytes by ____________
(long distance) diffusion
allografts of hyaline cartilage have been reasonably successful due to its _______ nature, which prevents large molecules such as immunoglobulins and cytotoxic T-cells from coming into contact with chondrocytes
avascular
What happens once chondrocytes die?
the matrix is invaded by blood vessels and macrophages remove the devitalized cartilage.
Where is elastic cartilage located? (3)
- external ear
- auditory tube
- epiglottis
elastic cartilage is similar to hyaline cartilage except that …
elastic fibers rather than collagen fibers comprise the fibrillar component of the extracellular matrix
_________ is a specialized connective tissue, where tendons and ligaments insert on bone or cartilage
fibrocartilage
_______ resembles dense regular connective tissue with a predominance of type I collagen fibers and scanty amounts of amorphous ground substance
fibrocartilage
fibrocartilage resembles dense regular connective tissue with a predominance of type ___ collagen fibers and scanty amounts of amorphous ground substance
type I
2 principle sites of fibrocartilage
- annulus fibrosis of the intervertebral discs
- menisci of the stifle joint
2 mechanisms by which growth of cartilage occurs.
- appositional growth
- interstitial growth
______: involves the deposition of new cartilage at the surface (perichondrium) by chondroblasts
Appositional growth
______: involves the division of chondrocytes within lacunae and the production of matrix, resulting in expansion by new cartilage from within.
Interstitial growth
The division of chondrocytes in interstitial growth results in _____ of chondrocytes, the progeny of a single chondrocytes.
Isogenic clusters
The _____ is primarily responsible for lengthening the bone.
Epiphyseal growth plate (or physis)
Three zones of the epiphyseal growth plate.
- reserve/resting zone
- proliferative zone
- hypertrophic zone
The hypertrophic zone of the growth plate is further divided into what three zones?
- maturation zone
- degeneration zone
- calcification zone
________: acts as the source of cells for the proliferative zone in the growth plate
Reserve/resting zone
______: where cells of the growth plate multiply, accumulate glycogen, produce matrix, and become arranged in longitudinal columns
Proliferative zone
______: where chondrocytes of the growth late secrette macromolecules that modify the matrix to allow capillary invasion and initiate matrix mineralization (these chondrocytes eventually die)
Hypertrophic zone
_________ is a critical step in endochondral ossification
Vascular invasion of the growth plate
The _______ in the metaphysiss is a fragile lattice of bone-coverred spicules of calcified cartilage.
Chondro-osseous junction
_______: The spongy substance of bone that is initially formed after the replacement of cartilage, and consists of mineralized tissue, marrow and cartilage
Primary spongiosa
________: The area of the metaphysis composed of more mature trabeculae (lamellar bone) which become fewer and thicker.
Secondary spongiosa
Bones grow in width by _______
Intramembranous bone formation
Except for _____, the surfaces of bones are covered by periosteum.
Articular surfaces
Except for articular surfaces, the surfaces of bones are covered by ______
Periostium
The periostium is composed microscopically of an outer __________ and an innerr _____ or ______ layer
- fibrous layer
- osteogenic or cambium layer
_____: the layer of the periostium that provides structural support
Fibrous layer
________: the layer of the periostium that is capable of forming both normal lamellarappositional bone on the cortex of growing bone and abnormal woven bone formation in response to injury.
Osteogenic or cambium layer
The periostium covering the physis is called the _________
Perichondrial ring
What is the function of the perichondrial ring?
The perichondrial ring adds new cartilage tto the periphery opf the physis, enabling the physis to expand in width.
The articular surfaces are composed of ______ supported by underlying ______
- articular cartilage
- subchondral bone
Growth of articular cartilage is achieved via _____
Interstitial growth
Following cessation of growth, articular chondrocytes are no longer able to divide, but are capable of producing ________
Additional cartilage matrix
Most nutrients to articular cartilagee are recieved by _____ from the _______
- diffusion
- synovial fluid
Four cartilaginous zones
- superficial (tangential) zone
- transition zone
- radial zone
- deep zone
The junction bettween the radial zone and tthe calcified cartilage is known as the ______
Tidemark
______: cartilage layer which is a narrow zone of small, flattened chondrocytes aligned parallel to the articular surface
superficial (tangential) zone
______: cartilage layer which is made up of chondrocytes with an ovoid morphology
transition zone
______: cartilage layer where the chondrocytes are aligned in longitudinal rows perpendicular to the articula surface
radial zone
______: cartilage layer of calcified cartilage that interlocks with the subchondral bone to anchor the articular cartilage.
deep zone
the alignment of chondrocytes corresponds with the alignment of the ___________ within the extracellular matrix
type II collagen fibers
the junction between the _________ and the __________ is known as the tidemark
- radial zone
- calcified cartilage
growth of the epiphysis contributes to the overall length of the bone and is accomplished by endochondral ossification at the __________
articular-epiphyseal (AE) complex
___________: the zone of endochondral ossification beneath the articular cartilage in growing animals
articular-epiphyseal (AE) complex
_______: the center of the intervertebral disc
nucleus pulposus
________: the periphery of the intervertebral disc
annulus fibrosus
