Block IV: Elastic cartilage & fibrocartilage Flashcards
Where can we find elastic cartilage?
auricles, auditory tube, larynx
How is elastic cartilage different from hyaline cartilage?
- Less matrix
- Network of elastic fibers in the matrix and perichondrium
- Larger and more abundant chondrocytes
- Yellowish color in living individual
- Does not calcify with age
identify
elastic cartilage, elastic fibers and perichondrium
WHat stains elastic cartilage from the epiglottis?
Elastic cartilage from the epiglottis stained with orcein that reveals elastic fibers in matrix
By what is elastic cartilage distinguished?
by the presence of elastin in the cartilage matrix
identify
elastic cartilage from epiglottis stained with orcein
Where can we find fibrocartilage?
(intervertebral discs, symphysis pubis, temporomandibular joints, menisci of the knee joint
What is the composition of fibrocartilage?
It is a combination of dense regular connective tissue and hyaline cartilage
How are chondrocytes in fibrocartilage?
Similar to the chondrocytes of hyaline cartilage, but they have considerably less cartilage matrix material. The chondrocytes are dispersed among the collagen fibers singularly, in rows, and in isogenous groups.
Where is the perochondrium in fibrocartilage?
NO surrounding perichondrium
What is the main function of fibrocartilage?
resistance to both compresion and shearing forces; synthesis of collagen II
identify
identify
What type of collagen is present in the matrix of fibrocartilage?
type I collagen and type II collagen.
What factors affect the proportion of collagens type I and II?
Mechanical forces, nutritional changes, and changing levels of hormones and
growth factors
WHat makes the ratio between collagen type I and II change?
age; thus, in older individuals there is more type II collagen because of the metabolic
activity of chondrocytes
What does the extracellular matrix of fibrocartilage contain?
larger amounts of versican (a proteoglycan monomer secreted by fibroblasts) than aggrecan (produced by chondrocytes
what is intervertebral disc degeneration associated with?
proteolytic degradation of proteoglycan aggregates present within the extracellular matrix.
identify
fibrocartilage
identify
chondrosarcoma
What method is used to determine stage of tissue differentiation?
Immunohistochemical localization of collagen types
what indicated mature tumors with good prognosis?
The presence of collagen types II and X and the proteoglycan aggrecan in
biopsies
What indicated poor prognosis of tumors?
The presence of collagen type I indicates changes in the extracellular
matrix toward dedifferentiated (fibrous)
What transcription factor is present in chondrosarcomas?
Transcription factor SOX-9
Identify
Photomicrograph of a tracheal ring from an elderly individual, stained with H&E. The
darker, basophilic areas on the left side of the micrograph represent normal cartilage matrix (C).
The lighter and more eosinophilic areas represent bone tissue (B) that has replaced the original cartilage matrix. A large marrow cavity has formed within the cartilage structure and is visible in the center of the micrograph.
Why does calcification happens?
Calcification always occurs in cartilage that is about to be replaced by bone
(endochondral ossification) during an individual’s growth period.
Hyaline cartilage in the adult calcifies with time as part of the aging process.
Cartilage has limited ability for repair
