Lecture 10 - bone and cartilage Flashcards
What are the three types of cartilage?
Hyaline
Elastic
Fibro
Where are the three types of cartilage located?
Cartilege is part or all of the skeletal system (which begins as cartilege)
- Hyaline
- external auditory meeatus
- larynx
- tracheal cartilages
- bronchial cartilege
- fetal long bones
- articular end of bones
- Elastic
- Auricle (pinna of ear
- Epiglottis
- Fibro
- Intervertebral discs
- pubic symphsysis
- insertion of some tendons and ligaments
- closely associated with dense CT or Hyaline cartilege
What types of cells are assocated with cartilage?
Chondroblasts- (cartilege forming cells)
Chondrocytes (cartilage maintainence cells)
What is associated with the matrix of cartilage?
- Amorphus ground substance
- Collagen fibers
- type II collagen in HYALINE AND ELASTIC
- TYPE I in FIBRO
What is a lacunae?
Pockets w/ in the matrix where C. blasts/Cytes are found
or
Pockets within bone (haversian system) where osteocytes are found
What are the characteristics of cartilage?
- Lacune = house C. blasts/Cytes
- C blasts build cartilage and matrix
- C. Cytes. maintains them
- Avascular
- diffusion from blood vessels outside of cartilege
What is the structure of cartilage?
- Perichondrium
- Outer fibrous layer
- contains fibroblasts
- Inner chonidrogenic layer
- C. blasts formed then mature to become C. cytes
- C cytes involved in production of colagen adn proteoglycan and secrete chondro nectin
- Outer fibrous layer
- Isogenous group
- 2 - 8 C. Cytes that occupy lacunae
- result of mitotic division
- cells become seperated as they begin to lay down matrix of their own
- Matrix
What are the componets of the matrix? and what are its subdivisions?
- Collagen type 2 (type I for fibro)
- Hyaluronic acid (hyaluranon)
- Chrondronitin Sulfate, keratin sulfate, heparin sulfate
- GAGs
Subdivsions
Territortial Matrix
- surrounds each C. Cyte
- High GAG to Low Collagen ratio
Interterritioral Matrix
- Surrounds territoral Matrix
- High Collagen to Low GAG ratio
WHat are the characteristics of Hyaline cartilage?
- TYPE II Collagen Fibers (on TEST)
- Avascular
- Most common
- Surrounding Perichondrium
- Solif but flexable
- Chrondrocytes are group
- Growth Pattern
- Appositional (width)
- Interstitial Grown (from within)
- Blue/ gray to white translucent
What is elastic cartilage?
Surrounded by perichondrium
yellowish b/c elastic fiber
move opaque , flexible, and elastic than hyaline
C cytes are located singly
type 2 collagen w/ elastic fibers
What are the characteristics of fibro cartilage?
Increased collagen in matrix
reuced cellularity
not surronded by perichondrium
type 1 collagen
single sparse C cytes
Opaque appearance
What are these tissues
Hyaline
What are these tissues?
Elastic
What are these tissues
Fibro
What are the three types of bone tissue ?
Woven
Spongey (trabeuclar, cancellus )
Compact (lamellar)
What are the characteristics of woven bone?
In bone development and repair
Produced rapidly
less structural intregrity (haphazard collagen foundation)
What are these tissues?
What is the structure of compact bone ?
Lacks cavities seen in developing bone
Form dense plates outside long or flate bone
Concentric (haversian ) lammellae - encircle blood vessels and nerves and forms ostean or haversion system
Osteocytess occuring in lacunae b/w lamellae and are connected to each other via haversion canal, via canaliculi
volkmanns canal runs perpendicular and connect the haversian canals to each other and to the surface of the bone
What is the histological anatomy of bone structure ina typical long bone?
What are the four types of cells involved in bone formation, maintenance , and reabsorption
- Osteoblasts
- secretes bone matrix
- secretes collagen and catalyzez minerlization
- osteocytes
- maintain bone matrrix
- control Ca2+ and Phosphate lvls
- Osteoclasts
- Remodels bone through bone resportion
- Osteoprogenitor cells
- stem cells in adult described as bone lining cells found in inner portion of periostem in endotesium and lining of vascular canals
What are characteristics of osteoblasts?
- come form osteoprogenitor cells
- give rise to osteocytes
- characterized by
- alkaline phosphatase (not in osteocytes)
- vitamin D3 (regulates expresison of osteocalcin)
- Major protein products
- type 1 collagen
- non collagenous proteins
- osteoCalin (high binding addinity for hydroxyapaitie)
- ties mineral to organic (ONLY IMPORTANT ONE)
- osteonectin
- osteopontin
- osteoprogtegerin
- RANKL
- osteoCalin (high binding addinity for hydroxyapaitie)
What is the biochemical mechanism used to form osteoclasts?
Parathyroid hormone (PTH) binds of receptors on osteoblasts
Osteoblast is stimulated to synthesize MCSF (mono cycte colony stimulating factor) and increases RANK L expression
MCSF binds to MCSF receptor on Monocycte
Monocyte becomes macrophage and expresses RANK
RANK binds to RANK L on osteoblasts
causes Macrophage to beome multinucleated immature osteoclast
WHat is parathyroid hormone use for?
Low PTH levels = bone formation Osteoblasts stimulated
High PTH levels osteo blasrs are stimulated to release osteoclasts release factors
results in osteitis fibrosa and eroded bone
What biochemical mechanism occurs at adult remodeling sites?
ARF which is (activation resportion reversal formation) cycle occurs at adult removdeling sites during development
What are two major products secreted by osteoclasrs are involved in bone reabsorption?
- Cathepsin K
- A lysosomal protease involved in bone remodeling an resorption that can catabolize elastin, collagen, and gelatin (organic matrix)
- H+ and CL - ions
- dissolve the inorganic matrix
What tissue is this?
Songey, traebecular, cancellous
What tissue is this?
Compact or dry ground bone
What tissue is this?
Developing membrane bone (fetus)
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