Histology.7

Bone

cartilage has very limited ability to repair, it is avascular. A blood vessel near the wound site would generally promote the formation of this rather than cartilage. often hyaline cartilage will become calcified and will be replaced by bone.

Chondrocytes

main cell type of cartilage that produces and maintains the cartilagenous matrix. These have euchromatic nuclei because they are active cells secreting type 2 collagen and other ECM components.

Periochondrium

outer layer of connective tissue around cartilage that is associated with both hyaline and and elastic cartilage only. This is found in cartilage that goes through apositional growth.

15

percent of hyaline cartilage that is made up of collagen. Of this value- type 2 makes up 80% of the collagens found here.

60-80

percent of hyaline cartilage that is made up of water. Proteoglycans and multiadhesion proteins are also important to help maintain this level of water.

Hyaline

the base form of cartilage, this is primarily made up of the glassy appearing ECM, the type 2 collagen fibers, and the chondrocytes in their lacunae. This is found in the respiratory structures- C rings of trachea, the embryonic skeleton, costal cartilage, articular cartilage, and epyphesial growth plates. This contains a perichondrium. Articular cartilage is also generally this type.

Interterritorial

the matrix that is between the clusters of chondrocytes, this stains lighter because more water is present and has been able to diffuse the ECM components.

Territorial

the matrix that is directly around the chondrocytes in the lacunae, this is darker because these cells are directly secreting proteins and components of the ECM and they havent diffused out greatly.

Isogenous

the name of the groups of chondrocytes that are formed due to their cell division, as the cells produce more ECM these will separate from one another and continue division. These are also called cell nests.

Compression

the proteoglycans and GAGs of the ground substance help to resist this force. High amounts of water prevent this from occurs. The collagen fibers have high tensile forces that resist tension or stretching forces.

Lacunae

the spaces in the ECM of cartilage and bone that the cells reside in.

Interstitial

type of cartilage growth that is when the cartilage expands from within, each isogenous group is producing more ECM that will move outwards. No perichondrium is required- this is the main form of growth for fibrocartilage. This also does not involve chondroblasts.

Appositional

type of cartilage growth that requires a perichondrium, the chondroprogenitor cells become chondroblasts, and chondroblasts mature into chondrocytes, cartilage expands in size from expansion at perichondrium.

Elastic

type of cartilage that is essentially hyaline cartilage, but also contains elastic fibers. Has a perichondrium and grows interstitially and apositionally. Gives more elastic properties, forms a dense network of fibers. Located in the auricle of the ear, external auditory meatus, eustachian tube, epiglottis, and larynx. Mostly type 2 collagen.

Fibrocartilage

type of cartilage that looks like a hybrid between hyaline cartilage and dense regular connective tissue. In is located in intervertebral disc, symphysis pubis, and attachment of tendons and ligaments to bone. Cells in single row and isogenous groups, combined with dense regular connective tissue. Mostly type 1 collagen. Only grows by interstitial growth- does not have a perichondrium.

Chondroblasts

type of cell in cartilage that do not yet have alot of matrix surrounding them, these are located near the perichondrium, and are derived from mesenchymal stem cells under the perichondrium.

1

type of collagen that is characteristically found in fibrocartilage. Located at intervertebral discs, symphysis pubis, and attachment of tendons and ligaments to bone.

Cartilage

type of hard connective tissue, that supports soft tissue, lines articular surfaces, connects various tissues, and is laid down as the developmental skeleton and in later turned into bone. This type of tissue has lots of ECM and has no nerve supply or blood flow. It is flexible and resilient. Glassy appearance with amorphous matrix and provides low friction.

Mesenchyme

type of stem cells that are stellate and will differentiate into chondroblasts and produce ECM and spread out and then further into chondrocytes.