(P) Lec 5: Bones and Cartilages Flashcards
Familiarize the functions of the bones
- Provides solid support for the body
- Protects vital organs
- Attachment for muscles, tendons, and ligaments
- Acts as levers by which movement is produced
- Reservoir of calcium, phosphate & other ions
These are:
- Undifferentiated cells capable of mitosis
- Mesenchymal stem cells
- Potential to proliferate and differentiate
into osteoblasts - Role in bone growth and repair
Osteoprogenitor Cells
Where did osteoprogenitor cells develop from?
Embryonic tissue
What does osteoblasts synthesize?
Osteoid
Main function of osteoblasts?
Bone formation
Where are osteoblasts found?
Lining surfaces of the bone matrix
Two types of osteoblasts
Active and Inactive
Osteoblasts that are cuboidal or columnar with basophilic cytoplasm
Active
Osteoblasts that are flat cells that line the endosteum and periosteum
Inactive
These are:
- Mature cells
- Flat, almond-shaped
- With cytoplasmic processes
- Found in cavities (lacunae)
- Between bone matrix layers (lamellae)
- Maintain bone matrix
Osteocytes
Where are osteocytes found?
Lacunae
The communication in osteocytes are through what?
Canaliculi
What is the main function of the osteocytes?
Maintains the bone matrix
These are:
- Motile, multinucleated giant cells
- Fusion of bone marrow derived cells
- Role in matrix resorption
Osteoclasts
Where do osteoclasts lie?
Within the resorption lacunae
The resorption lacunae is also called what?
Howship’s lacunae
These are produced by the fusion of bone marrow-derived monocytes
Osteoclasts
These erode the bone matrix during remodeling
Osteoclasts
What is the main function of the osteoclast?
Bone resorption
The Bone matrix is composed of what two part?
Inorganic and Organic
This makes up 50% of the bone matrix
Inorganic and Organic (they’re both 50%)
What is most abundant in the inorganic part of the bone matrix?
Calcium hydroxyapatite
This is also composed of Bicarbonate, citrate, magnesium, potassium, sodium ions; Calcium phosphate
Bone Matrix - Inorganic
The organic part of the bone matrix is composed of what type of collagen?
Type I
This has:
* Proteoglycan aggregates
* Multiadhesive glycoproteins
Bone Matrix - Organic
Two types of multi-adhesive glycoproteins
- Osteonectin
- Osteocalcin
What is the association of minerals with collagen fibers?
hardness and resistance of bone tissue
Cartilages are composed of what type of collagen?
Type II
What are the two fibrous coverings of the bone?
Periosteum and Endosteum
The periosteum is composed of which 2 layers?
Outer & Inner layer
Layer of periosteum composed of DCT, BVs, collagen bundles, fibroblasts
Outer layer
Layer of periosteum composed of:
- Perforating collagen fibers
- Penetrate bone matrix
- Bind periosteum to bone
Sharpey’s fibers
What bind periosteum to the bone?
Sharpey’s fibers
Layer of the periosteum that is more cellular, and has:
- Bone lining cells
- Osteoblasts
- Osteoprogenitor cells
Inner layer
This periosteum layer nourishes osseous tissue and provide continuous supply of new osteoblasts
Inner layer
Why can the inner layer of the periosteum provide a continuous supply of new osteoblasts?
It contains the osteoprogenitor cells
Fibrous covering of the bone that:
- Covers small trabeculae of bony matrix
that project into marrow cavities - Thinner
- Contains: Bone lining cells, Osteoblasts, Osteoprogenitor cells
Endosteum
What are the two main types of bones?
Compact/Cortical Bone and Cancellous/Trabecular/ Spongy
Type of bone that’s found in dense areas near the surface of a bone
Compact/ Cortical Bone
T or F: Compact bone doesn’t have interstitial lamellae
False
Type of bone that has parallel lamellae or densely packed osteons
Compact bone
The Compact bone composes how many percent of the total bone mass?
80%
The Spongy bone composes how many percent of the total bone mass?
20%
Type of bone that’s found in deeper areas
Spongy bone
The spongy bone has interconnected thin spicules or trabeculae covered by what?
Endosteum
Type of bone composed of numerous
interconnecting cavities
Spongy bone
This is the bone organization in adults, compact or spongy. Also characterized by multiple layers or lamellae of calcified matrix
Lamellar bone
These are organized either parallel to
each other or concentrically around a
central canal
Lamellae
What type of collagen fibers are aligned in parallel in each lamella?
Type I
This is a complex of concentric lamellae
Osteon or Haversian System
This is a small central canal in an osteon
Haversian canal
T or F: The osteon is interconnected by canaliculi
True
What are found in an osteon?
- Haversian canal
- Concentric lamellae
- Lacunae
- Osteocytes
- Canaliculi
T or F: Each osteon is a long cylinder perpendicular to the long axis of the diaphysis
False (parallel)
What is the cement line of an osteon?
The outer boundary
T or F: The osteon is reticular-rich
False (collagen-rich)
This is a perforating canal and how central canal communicate with another
Volkmann’s canal
What are the types of lamellae?
Concentric, Interstitial, External circumferential, and Inner circumferential
Type of lamellae organized around the central canal
Concentric
Type of lamellae between intact osteons
Interstitial
Type of lamellae located immediately beneath the periosteum
External circumferential
Type of lamellae around marrow cavities and can be found in deeper areas
Inner circumferential
What is the composition of a Haversian canal?
BVs, Ns, LCT, endosteum
puro abbrev luh slr jwu imy balik ka na
Refers to the first bone tissue to appear in embryonic development and in fracture repair
Woven Bone
The Woven Bone organization has what type of collagen?
Type I
This is replaced in adults by lamellar bone, EXCEPT near the sutures of the calvaria and in the insertions of some tendons
Woven Bone
T or F: Though the woven bone has a lower mineral content, it has more strength than the lamellar bone
False (Less strength)
T or F: Woven Bone is temporary
True
Two types of bone growth
Appositional and Interstitial
Refers to growth in circumference
Appositional Growth
Refers to growth in length
Interstitial Growth
Refers to when deeper layer of the periosteum is made of osteoblasts which are responsible for new bone formation
Appositional Growth
Refers to the continued ossification of cartilage at the ends of bones (epiphysis) until all are transformed into bone
Interstitial Growth
Two types of bone development
Intramembranous ossification and Endochondral ossification
In this bone development, osteoblasts differentiate directly from mesenchyme and begin secreting osteoid
Intramembranous ossification
In this bone development, a preexisting matrix of hyaline cartilage is eroded and invaded by osteoblasts, which begin osteoid production
Endochondral ossification
In intramembranous ossification, osteoblasts differentiate directly from ___ and begin secreting _____
mesenchyme, osteoid
In endochondral ossification, a preexisting matrix of hyaline cartilage is eroded and invaded by __________, which begin osteoid production
osteoblast
Contains GAGs and proteoglycans that interacts with collagen and elastic
fibers
Cartilage
Where are cartilages formed from?
embryonic mesenchyme
Refers to:
*Tough and flexible CT
*Extracellular matrix (ECM)
Cartilage
Familiarize the functions of cartilages
- Forms the framework supporting soft tissues
- Provides a shock-absorbing and sliding area for joints
- Facilitates bone movement
- Essential for the development and growth of bones, before and after birth
T or F: Cartilages have blood supply
False (Avascular)
Where do cartilages receive their nutrients from?
Perichondrium
They:
*Have low metabolic activity
*No lymphatic vessels and nerves
Cartilages
What are the two compositions of cartilages?
Chondrocytes and ECM
The ECM in cartilages are composed of what?
Fibers and Ground Susbtances
Which type of fibers are in the ECM of cartilages?
Collagen & elastic
The ground substances of ECM of cartilage is composed of what?
GAGs & proteoglycans
What are the types of cartilages?
*Hyaline
*Elastic
*Fibrocartilage
This is the temporal skeleton in the embryo replaced by the bone
Hyaline cartilage
The most abundant cartilage
Hyaline
Cartilage found in:
*Articular surfaces of movable joints
*Walls of larger respiratory passages
* Nose, larynx, trachea, bronchi
*Ventral ends of ribs
*Articulate with sternum
*Epiphyseal plates of long bones
Hyaline
Hyaline has which type of collagen?
Type II
Refers to the most abundant proteoglycan in Hyaline
Aggrecan
In this cartilage’s matrix, it refers to the
- Multiadhesive glycoprotein
- Binds with GAGs, collagen type II, integrins
- Mediates adherence of chondrocytes to ECM
Chondronectin
Refers to:
- Isogenous aggregates of round cells
- Occupy separate lacunae
Chondrocyte
Refers to:
- Young chondrocytes
- Elliptical in shape
- Found in periphery of cartilage
Chrondroblasts
Refers to:
- A layer of dense irregular CT
- Type I collagen and fibroblasts
- Within fibroblasts are progenitor cells
- Covers all hyaline cartilage EXCEPT articular cartilage
- Essential for growth and maintenance of cartilage
Perichondrium
This cartilage is found in:
*Auricle of ear
*Walls of external auditory canal
*Auditory tubes
*Epiglottis
* Cuneiform cartilage in larynx
Elastic
Refers to cartilage which is combination of hyaline & DCT
Fibrocartilage
Cartilages produce what type of collagen?
Collagen type II
T or F: Fibrocartilage, as a type of cartilage, has a perichondrium because it is avascular
False (No perichondrium)
This cartilage is found in:
- Intervertebral discs, pubic symphysis,
attachments of certain ligaments
Fibrocartilage
Two types of cartilage growth
Interstitial growth and Appositional growth
Growth in cartilage referring to mitosis of existing chondroblasts in lacunae
Interstitial
Growth in cartilage referring to formation of new chondroblasts peripherally from progenitor cells in perichondrium
Appositional
Cartilage
Homogeneous, with type 2 collagen
Hyaline
Cartilage
Type II collagen, aggrecan, and darker elastic fiber
Elastic
Cartilage
Has type 2 collagen and large areas of dense connective tissue with type I collagen
Fibrocartilage
Arrangement of chondrocytes in fibrocartilage
Rows
Cartilage
Provides smooth, low-friction surfaces in joints, structural support for respirator tract
Hyaline
Cartilage
Provides flexible shape and support of soft tissues
Elastic
Cartilage
Provides cushioning tensile strngth and resistance to tearing and compression
Fibrocarti
Refers to:
- Genetic disease
- Dense heavy bones
- Bone resorption is defective
- Overgrowth and thickening of bones
- Obliteration of marrow cavities
- Anemia and loss of WBCs
Osteopetrosis
Refers to:
- Immobilized patients, postmenopausal women
- Bone resorption exceeds bone formation
- Reduced bone mineral density
- calcium loss from bones
Osteoporosis
This is the most commonly used bone measurement test used to screen for osteoporosis
Central DXA
Screening age for Central DXA
65 years and above
Refers to:
- Brittle bone disease
- A group of related congenital disorders
- Osteoblasts produce deficient amounts or defective type I collagen due to genetic mutations
Osteogenesis Imperfecta
Refers to benign tumor
Chondroma
Refers to:
* Slowly growing malignant tumor
* Self metastasize
* Removed by surgery
Chondrosarcomma
Why does chondrosarcoma rarely metastasize?
No blood supply in chondrocytes
