Cartilage & Bone Flashcards
Protein and Mineral deficiencies: Factor in Cartilage Growth
Decrease in Growth
Mixed spicule
contains both calcified cartilage and bone
Lacunae
Cavities in the cartilage matrix that contain individual chondrocytes
What does osteoclast activity create?
Howship Lacunae
- area of bone resorption
- depression in matrix
Vit D deficiency: Factor in Cartilage Growth
abnormal growth because Vitamin D is needed for calcium absorption
Interstitial material of all cartilage
very hydrate- 60-80% by weight
1) Collagenous Fibers=Type II cartilage
2) Elastic Fibers= amorphous
3) Ground substance (GAGs)-3types
- Condroitin
- Keratan sulfate
- hyaluronic acid
Where is elastic cartilage located?
external ear
- auditory tube
- epiglottis
- cartilage of larynx
- septum of alveoli
Osseous Tissue
-general morphology
Differentiated and specialized for supporting weight
- dynamic
- continuously reorganized
- highly vascular (VS cartilage is avascular)
What are the 3 types of cartilage in the body?
1) Hyaline
2) Elastic
3) Fibrous
Appositional Growth
Type of Cartilage Growth
- growth at the surface
- proliferatin of chondrogenic cells into chondroblasts
Osteoclast
large, multinucleate cells
- rough edges
- eats bone
- contains ruffled border to increase surface area
- cytoplasmic processes and microvilli
- uses ameboid movement (motile)
- secretes lysosomes
- derived from the monocyte/macrophage lineage
How does the interterritorial matrix stain?
Poorly
-more acidophilic compared to territorial matrix
Where is cancellous bone found?
inner core of bones
-between the inner and outer table so the skull
epiphyses of long bones
Osteoporosis
can be due to increase osteoclastic function
- dense, heavy and brittle bones
- osteoclasts lack ruffled borders
- bone resorption defective
What is the function of fibrocartilage?
firm support with tensile strength
Parathyroid Hormone: osteoclast
Indirectly increases osteoclast activity by:
- Osteoclasts product cytokine called osteoclast stimulated hormone
- increases bone reabsorption
Interterritorial Matrix
In between isogenous groups
-contains more collagen fibers than territorial matrix
Organic matrix of bone matrix contains:
Type I collagen
- nonmineralized ground substance
- y-carboxglutamate contain phosphoproteins
Elastic Cartilage
Matrix fibers are collagenous and elastic in nature
-contains elastic fibers, type II Collagen, perichondrium
Perichondrium
-general characteristics
- a covering on all cartilage except articular cartilage and fibrocartilage
- Vascular
- inervated
T or F: Cartilage Tissue is avascular
True
Territorial matrix
- surrounds isogenous group
- contains more ground substance than capsule
- metachromatic-Chondroitin sulfate
Tendon
Muscle to Bone
Factors influencing cartilage:
1) Protein and mineral deficiencies
2) Vitamin C deficiency
3) Vitamin D deficiency
4) X-ray radiation inhibits or stops cell proliferation
5) Growth Hormone and Thyroxine required for normal growth
Cancellous Bone: Endosteum
- 1 cell layer thick
- made of active and inactive osteoblasts
- lines the spicules
Haversion canal contains:
blood vessels
- capillaries
- venules
- arterioles
- nerves
Cartilage and Bone
-General Considerations
Specialized types of CT
-bear weight and give rigidity
What determines different cartilage types?
composition of the matrix
How do capsules stain?
Dark, basophilic stain
What is the function of elastic cartilage?
Flexible support
Fibrocartilage
Lacks perichondrium, so growth depends on interstitial growth
- Contains few chondrocytes arranged in columns or rows
- acts as a transition tissue between hyaline cartilage, bone, and fibrous tissue
- coarse bundles of type I cartilage arranged in a herring patter
- also contains Type II cartilage
Capsule
Pericellular Matrix
-located immediately around the chondrocytes
Cement line
No organic matrix-where lamellae touch
What are the 2 types of cartilage growth?
-one thing in common
1) Appositional growth
2) Interstitial Growth
In Both synthesis of matrix contributions to growth of cartilage
Ligament
Bone to Bone
Osteoblast
Can proliferate
- immature
- synthetically active cell
- synthesizes organic components of matrix called OSTEOID
- releases vesicles containing alkaline phosphatase (ossified osteoid, immature bone and cartilage)
- Becomes active osteocyte
How does cartilage derive its nutrients when developing?
derived by diffusion rom capillaries and tissue fluids
-remember in developing cartilage capillaries are not uncommon
Structures outside the osteon in Compact bone
-describe
1) Innercirumferential lamellae
2) Endosteum->covers inner circumference of lammelae
3) Interstitial lamellae-between osteons
4) Outer circumferential lammellae
5) Volkmann’s canal
Whats another name for spongy bone
Cancellous bone
Which type of cartilage has the widest distribution?
Hyaline
Metachromatic
Chondroitin sulfate
Inorganic matrix of bone matrix contains:
Carbonate
- Citrate
- Mg2+
- Trace heavy metal
What is another name for bone?
Osseous tissue
What do cartilage and bone originate embryologically?
Mesenchyme tissue
Metalloproteinase
Enzyme produced by chondrocytes
-degrades cartilage material allowing cells to reposition themselves
Vit C deficiency: Factor in cartilage growth
Decreases in growth due to inadequate collagen synthesis
-Scurvy
What are the functions of bone?
- Protection
- support
- blood cell formation
- serves as sites of attachment for skeletal muscle
Developing Cartilage
- Proiliferation of chondrocytes within cartilage
- rationale for isogenous groups
Chondroblast
Spindle Shaped
-synthesize and deposit cartilage
Canaliculi
connect lacuna to lacuna
-contain capillaries
Volkmann’s canal
perpendicular to Haversian canal
-connects 2 Haversian canals
Where is Hyaline Cartilage located?
respiratory passages
- ventral ends of ribs
- bone surfaces within joints (articular cartilage)
Osteoclasts vs Osteoblasts with age
Osteoclasts are more active with age
- results in loss of bone mass
- in postmenopause women due to loss of estradiol osteoclast activity accelerates
Where is fibrocartilage located?
Intervertebral discs
- pubic symphysis
- lines tendon grooves
- at insertion of tendons and ligaments to bone
Endosteum
Covers inner surface of bone
-represents boundary between the bone matrix and marrow cavities
Inner circumferential lamellae
located beneath endosteum
-forms innermost layer of compact bone
How is osseous tissue classified?
Compact or spongy (cancellous)
-Based on density or mass of the tissue
What does the periosteum contain
- Osteogenic cells
- Fibroblasts
- Collagen
- Ground substance
Cartilage tissue contains nerves and lymphatics
False
Cartilage tissue lacks nerve and lymphatics
Proliferation defintion
rapid increase in numbers
How does the territorial matrix stain?
Basophilic
What are the 2 components of bone matrix? Describe
1) Organic (non calcified)matrix (24%)
- found in osteoid
2) Inorganic (calcified) matrix (76%)
- forms crystals composed of needles
- contains hydroxyapatite=major component
- crystals placed at 600-700A interval on collagen
X-ray radiation: Factor in Cartilage growth
Inhibits or stops cell proliferation
-result in decrease or cessation of growth
Lacuna
Space in bone matrix around an osteocyte
- seperates bone from matrix
- only contains one osteocyte
- un-mineralized material
Sharpeys fibers
Collagen fibers from periosteum
- continuous with collagen fibers of bone
- found at bone/tendon or ligament jucntion
What are the two types of bone in terms of gross anatomy
Cancellous (spongy) bone
Compact bone
Outercircumferiential lamellae
located beneath periosteum
-forms outer most layer of compact bone
Hyaline Cartilage
Most common type of cartilage
- forms the embryonic skeleton
- provides for longitudinal growth of bone
- fresh cartilage is bluish-white opaque
- transparent in thin sections
- TYPE II cartilage
- covered by perichondrium except at articular surface
What cartilage is a Perichondrium not found in?
Articular Cartilage
Fibrocartilage
What is the most common type of cartilage?
Hyaline
Physical Properties of cartilage tissue is characterized by:
-What gives cartilage these properties?
elastic firmness associated with support
-enables the tissue to withstand pressure and shear force
Due to:
- Organization of fibers and composition of ground substance
- Avascular
- lacks nerve and lymphatics
Osteomalacia
insufficient mineralization of bone matrix
- usually caused by deficiency of Vitamin D
- occurs in adults
Perichondrium contains:
- Chondrogenic cells
- Fibroblasts
- Collagen
- Ground substance
Osteons
Haversian system
- funcitonal unit of bone
- canal surrounded by layers of concentric lamellae (multiple layers)
Chondrocyte
completely surround by extracellular matrix
-produces the matrix and metalloproteinse
What is the purpose of cytoplasmic processes in osteocytes
- Allow for nutrient transfer from cell to cell
- gap junctions between cytoplasmic processes for communication
Which cartilage is more flexible between Hyaline Cartilage and Elastic Cartilage? Why?
Elastic cartilage is more flexible than hyaline cartilage due to an abundance of elastic fibers
canaliculi
tunnels that allow passage of cytoplasmic processes of osteocytes
Cartilage Canals
3mm
-may have blood vessels carrying blood somewhere else
Keratin sulfate
Type of GAG
-resists compression
What are the 2 molecules that osteoblasts secrete?
M-CSF
RANKL
both stimulate osteoclast formation
Interstitial growth
Type of Cartilage Growth
- cell division of preexisting chondrocytes
- occurs during early phases of cartilage formation
Cancellous Bone
(spongy bone)
- trabeculae or spicules lined by endosteum
- reduces the overall weight of bone
- provides room for blood vessels and a place for marrow to function as a hemopoietic compartment
- contains osteoid
Osteoid
Made by osteoblasts
- extracellular material
- nonmineralized
Isogenous Groups
Groups of 2-5 chondrocytes
- derived from a single progenitor cell
- contribute to interstitial growth
Periosteum
- Vascular
- Innervated
- dense fibrous CT
- covers external surface of bone
What is another name for compact bone?
Cortical Bone
Bone Matrix
AKA calcified matrix
Avascular
-intercellular calcified material
What does Compact bone contain
Osteons Haversion canal OSteocytes Canaliculi Lamellae Cement line Lamellar matrix alternates orientation to strengthen
Osteocyte
Mature
- isolated
- synthetically inactive, doesn’t make osteoid
- unable to divide
- Stellate cell body
- Cytoplasmic Processes
Calcitonin: Osteoclast
Directly inhibits osteoclast activity
-reduces bone reabsorption
Bone spicule
AKA trabecula
-surround by red marrow-(site of RBC formation) or yellow marrow (site of fat cell formation)
Mature cartilage
=Chondrocytes
- Made of isogenous groups
- 2 to 5 cells per group
What are cartilage and bone composed of:
Like CT proper composed of:
-cells, fibers, and ground substant
What is the hardest tissue in the body?
Bone, and forms the main constituent of the adult skeleton
