Cartilage Flashcards
Perichondrium
Connective tissue surrounding cartilage:
- Outer fibrous layer (fibroblasts, collagen type I)
- Inner cellular layer (chondrogenic precursors & chondroblasts)
- Blood vessels, nerves, lymphatics
- Repair & appositional growth
- Does NOT surround articular cartilage & fibrocartilage
What is represented in the image
Cartilage with perichondrium
what is depicted in the image
Perichondrium: dense CT sheath that surrounds cartilage. It acts as the capsule of the cartilage. It is formed by a dense layer of CT intermediate between dense irregular and dense regular. It contains abundant blood vessels, nerves, and lymphatics, as well as fibroblasts. The inner layer of the perichondrium contains cells that look like fibroblasts, but are really chondroblasts. Chondroblasts will differentiate into chondrocytes
label the arrows depicted in the image?
Label the areas circled blue
Chondrocytes
- fully differentiated ECM-forming cells (low mitotic activity)
- embedded in ECM
Spaces – lacunae Groups – isogenous units
What is depicted in the image ?
Chondrocytes
What is depicted in the image
Isogenous groups
Cells within a single lacuna
What do the green circles depict ?
Chondroblasts
• proliferating undifferentiated cells that begin to synthesize ECM elements
What type of cartilage is this?
Hyaline Cartilage
What type of cartilage is this?
Elastic Cartilage
What type of cartilage is this?
Fibrocartilage
Where is this cartilage located and what type is it ?
Trachea
Hyaline
Hyaline cartilage
Provides support, flexibility, & resilience. The most abundant skeletal cartilage.
- Fibrillar protein phenotype: type II collagen
- Highly hydrated matrix
Present in these cartilages:
- articular – covers the ends of long bones (articular cartilage)
- epiphyseal plates and fetal development
- costal – connects ribs to sternum
- respiratory – makes up larynx/trachea and reinforces air passages
- nasal – supports the nose
Hyaline cartilage function?
provides smooth, low-friction surfaces in joints, structural support for respiratory tract
What type of cartilage is this?
Hyaline
What type of cartilage is this?
Young Hyaline Cartilage
What type of cartilage is this?
Mature Hyaline Cartilage
Where is this cartilage located?
Trachea
What is depicted in the image?
• Covers surfaces of articulating bones in synovial joints. Does not heal (replaced by fibrocartilage scar tissue).
Articular hyaline cartilage is made up of 4 poorly demarcated zones:
- Superficial [SZ] (gliding surface – small rounded chondrocytes parallel to surface)
- Intermediate [IZ] (chondrocytes become larger and slowly change orientation)
- Deep [DZ] (large rounded chondrocytes arranged in vertical column)
- Calcified cartilage [CZ] (separates hyaline cartilage from subchondral bone)
What type of cartilage is this and what does the arrow indicate?
Articular cartilage
-This is not a perichondrium! The superficial zone of articular cartilage may appear dark due to changing matrix characteristics.
What is depicted by the image
Articular cartilage
What is depicted by the image
Fibrocartilage
What is depicted by the image
Fibrocartilage
Examples:
- menisci of synovial joints
- intervertebral discs (annulus fibrosis)
- pubic symphysis
- TMJ
- Point of attachment of tendons to bone
What type of cartilage is found here?
Fibrocartilage
Fibrocartilage function?
provides cushioning, tensile strength, & resistance to tearing & compression
Fibrocartilage
- Highly compressed with great tensile strength. Acts like a combination of dense CT & hyaline cartilage. No perichondrium.
- type I and II collagen
what is depicted in the image?
Fibrocartilage
What is depicted in the image
Fibrocartilage
ECM: extracellular matrix
Ch: chondrocytes within lacuna
C: type I collagen fibers (thin dark lines within ECM)
Elastic cartilage
- Similar to hyaline cartilage but contains elastic fibers. Maintains the shape of a structure while allowing flexibility.
- Fibrillar protein phenotype: type II collagen and elastin
Elastic cartilage examples?
epiglottis, external ear
What is depicted in the image
Elastic cartilage
What is depicted in the image
Elastic cartilage
What is depicted in the image
Elastic cartilage
What type of cartilage is this and where is it?
Elastic cartilage
Epiglottis
What type of cartilage is this
Elastic Cartilage
What is depicted in the image?
What is depicted in the image
Elastic cartilage
ECM: extracellular matrix
P: perichondrium
EF: elastic fiber (black fibers throughout ECM)
Ch: chondrocytes within lacuna
Cartilage formation
- Mesenchymal cells differentiation & aggregation
- Synthesis: collagen types, elastin, aggrecan
What is depicted in the image
Condensed mesenchyme
What is depicted in the image
Chondrogenesis
Chondrogenesis
Mature matrix formation
• Bound water facilitates diffusion of nutrients and oxygen to the cells of cartilage and confers a gellike matrix
What is depicted in the image
Chondrocytes in growing cartilage
Cartilage repair
- Limited ability to repair after injury
- Formation of repair cartilage from perichondrium (matrix of repair cartilage has mixed properties of hyaline cartilage and fibrocartilage)
What is depicted
Cartilage repair
Tumor in Cartilage tissue?
Chondrosarcoma
What is this
Chondrosarcoma
Chondrosarcoma
- Tumor in cartilage tissue
- Normal matrix
- Do not metastasize
- Treatment is surgical
Zone of reserve cartilage
- Farthest from the diaphysis
- Hyaline cartilage
- Proliferating
- Randomly arranged chondrocytes
What is depicted in the image by the arrow
Zone of reserve cartilage
What is depicted in the image by the arrow
Zone of proliferation
- Proliferating chondrocytes
- Beginning to form isogenous groups
- Arranged in rows parallel to the long axis of the bone
