Cartilage and bone week 2 Flashcards
What types of tissue are cartilage and bone considered?
specialized types of connective tissue
True or false: There are more cells than ECM in cartilage and bone.
False. There is more ECM than cells in cartilage and bone.
What resident cells in cartilage are responsible for its production? What cells have the same function in bone?
- chondrocytes
- osteocytes
What are the 2 main components of the ECM of cartilage and bone? What makes them special?
collagen fibers and GAGs (as is true for all connective tissues) but these components are arranged in such a way that makes cartilage and bone well suited to their skeletal functions
What type of embryonic connective tissue are cartilage and bone originated from?
mesenchymal connective tissue
What are the 3 types of cartilage? Generally, how do they differ?
- hyaline
- elastic
- fibrocartilage
- largely differ in the fiber content of their matrix
True or false: Cartilage is avascular and aneural.
True. Nutrients and wastes are supplied/taken away via diffusion. Pain in joints due to cartilage damage occurs in surrounding tissues.
What are characteristics of hyaline cartilage? (location, function, composition)
anatomical location
- embryonic skeleton
- costo-chondral junctions (junction btwn costal cartilage of ribs and sternum)
- articular surfaces of synovial joints
- external ear
- supporting structures: trachea, nose
- eustacian tube (links nasopharynx to middle ear)
- epiphyseal plates
functions
- resist compression
- provide smooth surfaces for articulation at diarthrodial joints
- cushioning
composition
- Collagens: primarily type II collagen but also minor amounts of types VI, IX, X, and XI which fxn to crosslink collagenous and non-collagenous components of the ECM
- aggrecan: rich in chroitin sulfate and keratan sulfate
- chondronectin: glycoprotein that mediates adherence of chondrocytes to type II collagen
- growth factors
What are lacunae?
small cavities containing chondrocytes
What are the territorial and interterritorial matrices (in cartilage)? What are the differences in their affinity for basophilic staining?
territorial matrix: matrix surrounding a group of chondrocytes (lacunae)
interterritorial matrix: matrix btwn chondrocytes in a lacunae
territorial matrix is slightly more basophilic (stains darker purple)
What are isogenous groups (in cartilage)?
groups of 2-8 cells in one lacuna suggesting that a cell has divided but daughter cells have not yet produced sufficient matrix to be separated
What is the perichondrium in cartilage?
cellular dense connective tissue layer containing stem cells that produces chondrocytes and ECM.
True or false: Articular surfaces of joint cartilage contain a perichondrium.
False. They do not contain a perichondrium which accounts for the poor capacity of articular cartilage to repair after injury (think of OA)
What are the 2 forms of cartilage growth and how do they differ?
interstitial growth: occurs from within cartilage by mitotic division of chondrocytes and expansion of the flexible matrix
appostional growth: growth by maturation of chondroprogentiors in the perichondrium and formation of new matrix below the perichondrium
What are the characteristics of elastic cartilage? (location, function, composition). What type of stain is used to identify it and why?
anatomical location:
- pinna of ear
- epiglottis
- larynx
- internal and external auditory tubes
is similar in appearance to hyaline cartilage with H&E staining. dense bundles of elastic fibers must be visualized with Orcein/Weigert staining. elastic fibers allow for deformability and resilience
What is fibrocartilage? (location, function, composition)
location
- intervertebral discs
- pubic symphysis
- tendon insertions of bone
is similar in structure of hyaline cartilage only with a dense network of collagen type I (stains with eosin) that is produced by fibroblasts within cartilage. looks very much like dense regular connective tissue with differences in lacunar arrangements and fiber arrays that are sometimes pinnate rather than linear in organization
What are the ways in which bone differs from cartilage?
- is mineralized (with exception of mineralization of hyaline cartilage in endochondral ossification and fibrocartilage during bone repair)
- highly vascular
- has nervous supply
- dynamic: able to remodel and repair itself. does so ~ every ten years
- is interactive with other tissues: produces hormones, growth factors to act on other cells
What are the functions of bone?
- support
- protection to vital tissues/organs
- locomotion: tendon and ligament attachments
- mineral deposition (calcium and phospate homeostasis). its ability to remodel allows it to play role in mineral homeostasis
- stroma for hematopoiesis