Lecture 10 Flashcards
Bone and Cartilage
What type of collagen is in cartilage? What is the exception?
Type II collagen -exception type 1 in fibrocartilage
What are isogenous groups?
2-8 chondrocytes occupying same lacunae -result of mitotic division **chondrocytes can undergo mitosis while in the matrix allowing cartilage to grow and expand from with in
What is the difference b/w territorial matrix and interstitial matrix?
Territorial = surrounds each chondrocyte -high GAG content and low collagen Interstitial = surrounds territorial matrix -low GAG content and high collagen
What type of cartilage and what stain?
Elastic cartilage
Orsin Stain
What type of cartilage, and what type of cells?
Fibrocartilage
Rows of chondrocytes and collage lined up parallel
Where is hyaline cartilage found?
What are the characteristics?
- most common type
- avascular
- type II collagen
- surrounded by perichondrium
- appositional and interstitial growth patterns
- external auditory meatus
- larynx
- tracheal and brochial cartilages
- articular ends of bones
Where is elastic cartilage found and what are its characteristics?
- elastic fibers
- perichondrium
- yellow color
- choncrocytes mostly located singly
- type II collage
- auricle
- epiglottis
Where is Fibrocartilage located and what are its characteristics?
- increased collagen in matrix
- reduced cellularity compared to hyaline
- NO perichondrium
- Type 1 collagen
- not many isogenous groups
- intervertebral discs
- pupic symphysis
- lined in rows w/ bundles of collagen following in rows
Bone is continuously __________.
Organic component = _________.
Inorganic component = __________.
- remodedled, reasbored, reconstructed
- osteoid
- hydroxiapatite
What are the 3 types of bones?
1) Woven bone = fetal development and Fx repair
- less structural integrity
2) Spongy bone = trabecular or cancellous
- 3D branching, bony spicules interwined to form trabeculae
- surrounds bone marrow spaces in long and flat bones
3) Compact bone = lamellar bone
- concentric layers
What structure does trabecular bone form?
Skull cap (calvaria)
Label all the structures
A = fibrous periosteum (links skeletal system)
B = osteogenic periosteum (osteoblasts here - appositional growth)
C = lacunae (where osteocytes are located)
D = Lamellae (encircle a central canal)
E = canaliculi (supply O2 and nutrients)
F = Haversian Canal (BV and associated nerves)
G = Volkmann’s Canal (run perpendicular to Haversian canal and connect the Haversian canals to eah other and to surface of bone)
Osteoclasts are very ______ and _________.
Osteoblasts are ______ stained and _______ shape, and located on the outside.
- large and multinucleated
- darkly, irregular
______ secrete bone matrix.
________ maintain bone matrix.
________ remodels bone through bone reabsorption.
- osteoblasts (also secrete collagen and catalyze mineralization
- osteocytes (help cntrl Ca+2 and phosphate levels)
- osteoclast (dissolve both organic and inorganic matrix)
Where do osteocytes derive from?
What gives rise to osteoblasts?
- Osteoblasts
- Osteprogenitor cells
Where does osteoproginator cells derive from?
What are they classified as and what do they do?
- mesenchyme of embryonic somites
- they are stem cells (which in adults are known as bone lining cells)
- they give rise to osteoblasts and bone lining cells
- mitotic potential
found in inner portion of periosteum, endosteum, and lining vascular canals
Describe osteoblast origin
Derived from osteoproginator cells
Give rise to osteocytes
characterized by: alaline phoshatase (not in osteocytes) and vitamin D3 (reg expression of osteocalcin)
major prtn products:
- osteocalcin = has high binding affinity for hydroxyapatite (mineral components)
- RANKL
Where do osteoclasts derive from?
Monocyte lineage
- ARF cycle occurs at adult remodeling sites and during development
- they are responsible for remodeling and repair of bones
What happens at low PTH
Increase bone formation by osteoblasts
What happens at high PTH?
Exteneded elevated PTH?
- osteoblasts stim to release osteoclasts for bone reabsorption
- eroded bone and fibrosis of the resulting spaces
