Cartilage and Bone Flashcards
(46 cards)
1
Q
cartilage and bone are…
A
specialized connective tissue
2
Q
properties of cartilage
A
- avascular –> doesn’t regenerate of heal well
2. lacks sensation b/c there is no dedicated nerve supply
3
Q
functions of cartilage
A
- support: adapted to bear weight
- movement
- framework for growth of long bones
4
Q
composition of cartilage
A
- cells (chondrocytes: cartilage cells) 3%
- multi-adhesive glycoproteins 5%
- proteoglycans 9%
- collagens: primarily type 2 15%
- water 60-80%
5
Q
perichondrium
A
dense connective tissue that surrounds cartilage
6
Q
2 layer of the perichondrium and their functions
A
- inner cellular layer: gives rise to new cartilage cells
2. outer fibrous layer: connective tissue layer (has blood vessels)
7
Q
perichondrium is not seen in (2)
A
- articular cartilage
2. fibro cartilage
8
Q
chondrocytes
A
specific cell of cartilage
9
Q
chondroblasts
A
immature chondrocytes
10
Q
extracellular matrix produced by chondrocytes contains (3)
A
- collagen type 2 fibers
- proteoglycans
- multi-adhesive glycoproteins
11
Q
cartilage is capable of 2 kinds of growth
A
- appositional
2. interstitial
12
Q
appositional cartilage growth
A
new cartilage forms on the surface of existing cartilage
-new cells derived from inner layer of perichondrium
13
Q
interstitial cartilage growth
A
new cell forms within an existing cartilage by mitotic division
14
Q
isogenous groups
A
clusters of chondrocytes that have recently divided (in interstitial cartilage growth)
15
Q
types of cartilage (3)
A
- elastic
- hyaline
- fibro-catilage
16
Q
elastic cartilage
A
- extra cellular matrix: type 2 collagen and elastic fibers
- chondrocyte arrangement: isogenous gorups
- surrounded by perichondrium
- located in the epiglottis, larynx, pinna or ear, and auditory tube
- function: shape and elasticity
17
Q
hyaline cartilage
A
- extra cellular matrix: type 2 collagen
- chondrocyte arrangement: isogenous groups
- surrounded by perichondrium except articular cartilage
- locations: trachea, bronchi, end of ribs, epiphyseal plates (growth plate)
- function: shape and flexibility, fetal skeleton, movement in joints
18
Q
fibro-cartilage
A
- extra cellular matrix: type 2 with type 1 added
- chondrocyte arrangement: parallel rows
- not surrounded by perichondrium
- locations: articular discs, intervertebral discs, pubic symphysis, tendon insertion
- function: resistant to compression, cushioning tensile strength
19
Q
osteoarthritis
A
- degenerative joint disease
- pathogenesis usually unknown
- related to aging and trauma
- type 2 collagen production is inhibited
- superficial layer is affected first but can extend to the bone
- affects hyaline cartilage most
- no treatment because cartilage is not regenerative
20
Q
degeneration of the intervertebral disc
A
- 4th disc is composed of nucleus pulpous (gelatinous material) and anulus fibrous (fibrocartilage)
- nucleus pulpous herniates though weakened though weakened anulus fibrosis
21
Q
properties of bone (6)
A
- well vascularized and highly innervated
- mineralized: results in hard tissue that supports and protects
- protects and serves as a supporting framework
- allows movement
- site of blood cell formation
- serves as calcium and phosphorus reserves for the body
22
Q
periosteum
A
2 layered sheath with an outer fibers layer of dense connective tissue and an inner cellular layer that covers the OUTER surface of bone
23
Q
endosteum
A
1 layer sheath of that contains osteoprogenitor cells that covers the INNER surface of bones
24
Q
macroscopic classification of bone (2)
A
- compact/ dense/ cortical
2. spongy/ cancellous
25
compact bone
- dense layer surrounding the outside bone
| - well organized "osteon" system
26
spongy bone
-forms a layer of trabeculae (thin spicules of bone tissue) in the interior of bone
27
microscopic classifications of bone (2)
1. primary/ immature
| 2. secondary/ mature/ lamellar
28
primary bone
- initially formed in skeleton of developing embryo and during bone repair
- irregular organization
- low mineral content
29
secondary bone
- organized structure replaces primary bone
- composed of concentric lamellae
- more calcified and stronger than primary bone
30
osteon
-structural units that make up mature bone
31
concentric lamella
formed by bone matrix that surround a central cavity that form osteons
32
haversian canal
the cavity that contains the blood and nerve supply for osteons
33
interstitial lamellae
remnants of previous concentric lamella between osteons
34
outer circumferential lamellae
outer surface of the shaft of a long bone
35
inner circumferential lamellae
inner circumference of the shaft of a long bone
36
volkmann's canals
- channels through which blood vessels and nerves travel from the periosteal and endosteal surfaces to reach the osteons
- connect one osteon to another and run at right angles to the long axis of the osteon
37
composition of bone
- inorganic components- 65% of weight of bone (mineralized calcium phosphate in the form of hydroxyapetite crystals)
- collagen type 1 (majority of organic components)
- multi-adhesive glycoproteins, proteoglycans, bone specific proteins
- cells (small %)
38
cells of bone (5)
1. osteoprogenitor cells
2. osteoblasts
3. osteocytes
4. bone lining cells
5. osteoclasts
39
osteoprogenitor cells characteristics
- derived from embryonic mesenchymal stem cells
- retain ability to undergo mitotic division
- function: responsive to stimuli then differentiate into bone , forming cells called osteoblasts
- location: inner periosteum layer or growing bone and endosteum lining the bone cavity
- structure: squamous shaped cells
40
osteoblast cells characteristics
- function: secrete type 1 collagen and bone matrix proteins which form unmineralized bone/osteoid
- capable of cell division
- location: areas where bone is being actively laid down
- structure: cuboidal shaped cell in single file along surface of bone (basophilic cytoplasm)
- communicate by gap junctions with each other and with osteocytes
- once they secrete product required for bone formation they are surrounded by bone matrix and become osteocytes
41
osteocyte cells characteristics
- function: maintain matrix of bone
- location: surrounded by matrix that it previously secreted as osteoblast
- respond to mechanical stimuli and can make new matrix as needed
- also have a small role in the breakdown of the matrix
- structure: flattened nucleus, overall conforms the shape of the lacunae
- occupies a lacunae and extends cytoplasmic processes through canaliculi (small canals) to contact processes of other osteocytes and bone lining
42
bone lining cells characteristics
- derived from osteoblast that are not actively producing bone
- function: support cells for osteocytes, and regulate calcium flow in and out of bone
- location: external and internal surfaces of bone
- structure: flat cells that cover the surface of bone
- incapable of mitotic division but capable of differentiating into osteoid secreting cells
43
osteoclast cells characteristics
- precursors derived in bone marrow, travel to bone and fuse to form large muti-nucleated osteoclast
- function: bone resorption, must be activated to become a resorbing cell
- structure: large, multi-nucleated cell found where bone is being formed
- location: surface of bone and occupy spaces called howship's lacunae
44
mechanisms of bone formation (2)
1. intramembranous ossification
| 2. endochondral ossification
45
intramembranous ossification general
bone formed by direct differentiation of mesenchymal cells into osteoblasts (clavicle, mandible, flat bone of the skull and face)
46
endochondral ossification general
cartilage model is the template fro bone formation (limb bones and weight bearing portion of the axial skeleton)
