p.1
Characteristics of Bone as Specialized Connective Tissue
Why is bone characterized as specialized connective tissue?
Bone has a unique structure and function that supports and protects organs, facilitates movement, and stores minerals.
p.1
Components and Organization of Bone
What are the main components of bone?
Bone is composed of cells, extracellular matrix, and mineralized components.
p.71
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is an Advanced Primary Ossification Center?
The area in a developing bone where ossification begins and progresses.
p.67
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What inhibits the diffusion of nutrients in endochondral ossification?
Calcified cartilage matrix.
p.51
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What must happen for newly formed osteoclasts to become bone resorbing cells?
They must be activated, a process involving osteoblasts.
p.84
Structure and Function of the Epiphyseal Plate
What happens to the cartilage matrix in the Zone of Hypertrophy?
It gets compressed into bands between the chondrocyte columns.
p.5
Components and Organization of Bone
What are the characteristics of bones in terms of shape and size?
Bones come in a variety of shapes and sizes.
p.10
Components and Organization of Bone
Where is yellow bone marrow primarily located?
In the medullary cavity of long bones.
p.86
Bone Growth Mechanisms: Length and Width
What causes the actual lengthening of bone?
New cartilage formation pushes the epiphysis away from the diaphysis.
p.34
Components and Organization of Bone
What is the main difference between decalcified and ground sections of bone?
Decalcified sections involve removing calcium, while ground sections involve grinding the bone to a thin layer without removing minerals.
p.72
Types of Bone Tissue: Mature vs. Immature Bone
What is calcified cartilage?
A type of cartilage that has undergone calcification, making it more rigid.
p.25
Types of Bone Tissue: Mature vs. Immature Bone
How does Woven Bone differ from Lamellar Bone?
Woven Bone has a less organized structure compared to Lamellar Bone.
p.63
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What do osteoblasts lay down around the mid part of the cartilage model?
A cuff of bone known as the bony collar.
p.63
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the first sign of ossification?
The formation of the bony collar.
p.68
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What leads to the migration of cells into the cavity during endochondral ossification?
Blood vessel growth into the cavity.
p.51
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What role do osteoblasts play in relation to osteoclasts?
Osteoblasts are involved in the activation process of osteoclasts.
p.34
Components and Organization of Bone
What is the purpose of ground sectioning of bone?
To create thin slices of bone for detailed histological analysis.
p.24
Types of Bone Tissue: Mature vs. Immature Bone
What are the two types of bone tissue?
Mature Bone and Immature Bone.
p.24
Types of Bone Tissue: Mature vs. Immature Bone
What is another name for Immature Bone?
Non Lamellar Bone, Bundle Bone, or Woven Bone.
p.30
Components and Organization of Bone
What are lacunae in mature compact bone?
Small hollows within the matrix where osteocytes are located.
p.71
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is endochondral ossification?
A process where bone develops by replacing hyaline cartilage.
p.71
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What are Mixed Spicules?
Structures formed during ossification that contain both cartilage and bone.
p.24
Types of Bone Tissue: Mature vs. Immature Bone
What are the characteristics of Immature Bone?
Large numbers of randomly arranged cells, randomly arranged collagen bundles, more ground substance than mature bone, and not heavily mineralized.
p.55
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the function of osteoclast cells?
They are responsible for bone resorption, breaking down bone tissue.
p.55
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is Howship’s Lacuna?
A small cavity or depression in bone where osteoclasts reside and perform bone resorption.
p.27
Components and Organization of Bone
What is an osteon?
The basic structural unit of compact bone.
p.27
Components and Organization of Bone
What is the Haversian canal?
A central canal in an osteon that contains blood vessels and nerves.
p.27
Components and Organization of Bone
What do interstitial lamellae represent?
Remnants of old osteons found between newer osteons.
p.34
Components and Organization of Bone
What is a decalcified bone preparation?
A method used to prepare bone samples by removing calcium to allow for microscopic examination.
p.17
Components and Organization of Bone
What are Sharpey's fibers?
Fibers that enter the bone matrix obliquely.
p.17
Components and Organization of Bone
Where do Sharpey's fibers extend into the bone matrix?
Into the outer circumferential and interstitial lamellae.
p.28
Components and Organization of Bone
How are osteons arranged in mature compact bone?
They are arranged with their long axis parallel to the long axis of the bone.
p.37
Components and Organization of Bone
What are osteons?
Structural units of compact bone, consisting of concentric lamellae surrounding a central canal.
p.28
Components and Organization of Bone
How is collagen arranged in concentric lamellae of osteons?
Collagen fibers are laid parallel to one another in any given lamella.
p.37
Components and Organization of Bone
What are Outer Circumferential Lamellae?
Layers of bone tissue that encircle the outer surface of the bone, providing structural support.
p.78
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What happens to the cartilage model during bone development?
It is almost entirely transformed into bone.
p.78
Components and Organization of Bone
Where is the remaining cartilage found after the transformation of the cartilage model?
In the epiphyseal disk and at the articular surface.
p.25
Types of Bone Tissue: Mature vs. Immature Bone
What is the mineralization level of Woven Bone?
It is less mineralized than Lamellar Bone.
p.55
Components and Organization of Bone
What is a bone spicule?
A small, needle-like structure in bone that contributes to its overall architecture.
p.32
Components and Organization of Bone
How do Volkmann’s Canals connect Haversian canals?
They connect Haversian canals to each other.
p.86
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What happens to cartilage as bone is laid down on calcified spicules?
The cartilage is resorbed, leaving spongy bone.
p.30
Components and Organization of Bone
What do canaliculi contain?
Processes of osteocytes in living bone tissue.
p.21
Types of Bone Tissue: Mature vs. Immature Bone
What is mature spongy bone?
It is a type of bone that has a porous structure, found mainly at the ends of long bones and in the interior of others.
p.86
Processes of Bone Formation: Intramembranous and Endochondral Ossification
How is spongy bone remodeled?
Through osteoclastic activity and the addition of new bone.
p.5
Components and Organization of Bone
What is notable about the internal and external structure of bones?
Bones have a complex internal and external structure.
p.32
Components and Organization of Bone
What are the main components of mature compact bone structure?
Osteons or Haversian Systems, Haversian Canals, Volkmann’s Canals, Interstitial Lamellae, Circumferential Lamellae.
p.75
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What part of the cartilage model is replaced by bone during endochondral ossification?
The mid part of the cartilage model, known as the diaphysis.
p.60
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What results from further growth and remodeling during intramembranous ossification?
Replacement of woven bone by compact bone in the periphery and spongy bone in the center.
p.4
Components and Organization of Bone
What is the organic matrix of bone made up of?
The organic matrix is mainly composed of collagen fibers and non-collagenous proteins.
p.9
Components and Organization of Bone
Where is red bone marrow primarily found?
In the spaces of trabecular bone.
p.4
Components and Organization of Bone
What role does water play in bone composition?
Water helps maintain the structure and function of bone tissue.
p.79
Structure and Function of the Epiphyseal Plate
What is the role of the epiphyseal growth plate in long bone growth?
It is essential for growth in length.
p.40
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What can osteoprogenitor cells differentiate into?
Osteoblasts and chondroblasts.
p.59
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What happens to osteoid after it is formed?
It later calcifies, and osteoblasts become trapped in lacunae, turning into osteocytes.
p.82
Structure and Function of the Epiphyseal Plate
What is the function of the proliferative zone in the growth plate?
Chondrocytes rapidly divide and contribute to the lengthening of the bone.
p.12
Structure and Function of the Epiphyseal Plate
Where is the Epiphyseal Plate located?
In the metaphysis at each end of a long bone.
p.82
Structure and Function of the Epiphyseal Plate
What happens in the hypertrophic zone of the growth plate?
Chondrocytes enlarge and prepare for the process of ossification.
p.28
Components and Organization of Bone
What is the arrangement of collagen fibers between adjacent lamellae?
The fibers are arranged in different directions.
p.73
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What are the two possible fates of the remaining bone component of a mixed spicule?
It may continue to grow by appositional growth or undergo resorption.
p.32
Components and Organization of Bone
What are Volkmann’s Canals?
Channels that allow blood vessels and nerves to travel from the periosteum and endosteum to the Haversian canal.
p.30
Components and Organization of Bone
What happens to canaliculi in terms of connectivity?
Canaliculi may anastomose with each other.
p.59
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the structure of collagen fibers in osteoid during the initial stage?
They form a woven network without a preferential orientation.
p.53
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What does the plasma membrane of osteoclasts do in the Clear Zone?
Forms a tight seal with the bone matrix.
p.40
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
Why are osteoprogenitor cells important?
They are important for bone repair and cartilage formation in fracture sites.
p.76
Structure and Function of the Epiphyseal Plate
What is the transverse disc between the epiphyseal and diaphyseal cavities called?
Epiphyseal growth plate or epiphyseal disc.
p.59
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
How do osteocytes communicate with each other?
By cytoplasmic processes.
p.19
Components and Organization of Bone
What is red bone marrow composed of?
Blood cells in different stages of development and a network of reticular cells and fibers.
p.19
Components and Organization of Bone
Where is red marrow restricted to in mature adults?
Spaces of spongy bone in the sternum and iliac crest.
p.42
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What do osteoblasts secrete?
Unmineralized bone matrix or osteoid.
p.48
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the five cell types found in bone tissue?
Osteoprogenitor Cells, Osteoblasts, Osteocytes, Bone Lining Cells, and Osteoclasts.
p.14
Periosteum and Endosteum: Structure and Function
What does the periosteum consist of in a bone where active bone formation is not in progress?
Mostly an outer fibrous layer of dense connective tissue, vessels, and nerves, with a poorly defined inner cellular layer.
p.1
Types of Bone: Compact, Cancellous, Woven, and Lamellar
What is woven bone?
An immature form of bone that is formed quickly and has a haphazard organization of collagen fibers.
p.85
Structure and Function of the Epiphyseal Plate
What is formed as a result of osteoblast activity on calcified cartilage?
Mixed spicules are formed.
p.66
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What does the secretion of alkaline phosphatase lead to?
Calcification of the cartilage matrix.
p.25
Types of Bone Tissue: Mature vs. Immature Bone
What characterizes Woven Bone?
It has a haphazard organization of collagen fibers.
p.54
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What happens to transport vesicles in the basolateral region of osteoclasts?
They fuse with the cell membrane to release digested bone material.
p.80
Bone Growth Mechanisms: Length and Width
What is the primary function of the growth plate?
To facilitate the lengthening of bones during growth.
p.30
Components and Organization of Bone
What is the function of canaliculi in bone tissue?
They allow communication between osteocytes and serve as a passage for substances between osteocytes and blood vessels.
p.52
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the ruffled border of osteoclasts?
Part of the cell in direct contact with the bone, containing numerous plasma membrane infoldings.
p.52
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What type of structures are found in the ruffled border of osteoclasts?
Microvillous type structures.
p.53
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
How are actin filaments arranged in the Clear Zone?
In a ring-like structure surrounded by actin binding proteins.
p.76
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What structures are formed as a result of the changes in epiphyseal cartilage?
Bone spicules, trabeculae, and bone marrow.
p.47
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
Where are osteocytes located?
In small spaces called lacunae within the bone matrix.
What types of blood cells are produced by bones?
Red and white blood cells.
p.26
Components and Organization of Bone
What does the osteonal canal (Haversian canal) contain?
Blood vessels, nerves, and connective tissue.
p.39
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the primary function of yellow marrow?
It serves as a fat storage area in the bone.
p.3
Components and Organization of Bone
What is a bone?
An organ of the skeletal system.
p.3
Components and Organization of Bone
What is bone tissue?
A specialized connective tissue that is a structural component of bone.
p.42
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
Name some bone matrix proteins secreted by osteoblasts.
Calcium binding proteins, multiadhesive glycoproteins, proteoglycans, alkaline phosphatase.
p.1
Types of Bone: Compact, Cancellous, Woven, and Lamellar
What is cancellous bone?
A spongy type of bone found inside bones, characterized by a porous structure.
p.49
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the characteristic staining property of osteoclasts?
They are highly acidophilic.
p.1
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is an osteon?
The basic structural unit of compact bone, consisting of a central canal surrounded by concentric layers of bone matrix.
p.54
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the function of the basolateral region in osteoclasts?
It functions in the exocytosis of digested material.
p.84
Structure and Function of the Epiphyseal Plate
What characterizes the chondrocytes in the Zone of Hypertrophy?
They are greatly enlarged and have clear cytoplasm due to glycogen accumulation.
p.24
Types of Bone Tissue: Mature vs. Immature Bone
When is Immature Bone formed?
Initially formed in the skeleton of a developing fetus.
p.32
Components and Organization of Bone
In what direction do Volkmann’s Canals penetrate the bone?
Perpendicular to its long axis.
p.68
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What type of cells migrate into the cavity during endochondral ossification?
Periosteal mesenchymal cells and hemopoietic stem cells.
p.21
Types of Bone Tissue: Mature vs. Immature Bone
What is lamellar bone?
It is a mature bone tissue characterized by its organized structure, consisting of parallel layers of collagen fibers.
p.75
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the cartilage remaining at the ends of the model called?
Proximal epiphyseal cartilage and distal epiphyseal cartilage.
p.88
Bone Growth Mechanisms: Length and Width
What occurs to the cartilage that has already been produced after maximal growth?
It continues to deposit bone until no more cartilage is left.
p.44
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the primary function of osteoblasts?
To form new bone by synthesizing and secreting the bone matrix.
p.11
Types of Bone: Compact, Cancellous, Woven, and Lamellar
What is compact bone?
A dense and strong type of bone that forms the outer layer of bones.
p.58
Processes of Bone Formation: Intramembranous and Endochondral Ossification
When does intramembranous ossification begin?
At the 8th week of gestation.
p.11
Components and Organization of Bone
How is compact bone organized?
It is organized into structural units called osteons or Haversian systems.
p.11
Components and Organization of Bone
What is the composition of compact bone?
It is primarily composed of mineralized matrix and collagen fibers.
p.81
Structure and Function of the Epiphyseal Plate
What are the two surfaces of the epiphyseal plate?
Epiphyseal surface and diaphyseal surface.
p.48
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
Where are Endosteal Cells located?
On the internal bone surface.
p.77
Processes of Bone Formation: Intramembranous and Endochondral Ossification
How is the epiphyseal plate formed?
Through the proliferation and maturation of chondrocytes in the growth plate.
p.43
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the primary function of osteoblasts?
To initiate mineralization of bone matrix.
p.2
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is a primary ossification center?
The first area of a bone to start ossifying.
p.43
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
How do osteoblasts appear under light microscopy?
They are cuboidal or polygonal shaped.
p.56
Clinical Correlates: Osteoporosis and Osteopetrosis
What does greater bone fragility in osteopetrosis lead to?
Increased risk of fractures.
p.24
Types of Bone Tissue: Mature vs. Immature Bone
What is a lamella?
Plates of collagen fibers cemented by the mineralized matrix.
p.15
Periosteum and Endosteum: Structure and Function
How does periosteal connective tissue align in relation to the bone surface?
It generally runs parallel to the bone surface.
p.63
Processes of Bone Formation: Intramembranous and Endochondral Ossification
How is the bony collar formed?
By intramembranous ossification.
p.60
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What does newly formed bone appear as during intramembranous ossification?
Irregularly shaped spicules and trabeculae.
p.83
Structure and Function of the Epiphyseal Plate
What characterizes the Resting Zone or Zone of Reserved Cartilage in the growth plate?
No cell proliferation or active matrix production.
p.5
Components and Organization of Bone
What is the smallest bone in the human body?
The stapes in the middle ear.
p.82
Structure and Function of the Epiphyseal Plate
What is the zonal arrangement of growth plate cartilage cells?
It refers to the organization of cartilage cells in distinct layers within the growth plate.
p.44
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What do osteoblasts secrete to initiate bone formation?
Osteoid, which is the unmineralized organic component of the bone matrix.
p.44
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What happens to osteoblasts once they become surrounded by bone matrix?
They differentiate into osteocytes.
p.19
Components and Organization of Bone
What does the marrow cavity contain?
Red bone marrow and yellow bone marrow.
p.47
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the function of the osteocytic process?
To communicate with other bone cells and exchange nutrients.
How do bones assist in muscle movement?
By providing attachment to muscles and functioning as levers.
p.48
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
Where are Periosteal Cells located?
On the external bone surface.
p.14
Periosteum and Endosteum: Structure and Function
What covers the outer surface of bones?
Periosteum, except in areas where they articulate with another bone.
p.46
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the five cell types in bone tissue?
Osteoprogenitor Cells, Osteoblasts, Osteocytes, Bone Lining Cells, Osteoclasts.
p.57
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What characterizes Intramembranous Ossification?
Mesenchymal tissue is directly replaced by bone without a cartilage model.
p.57
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What are examples of bones formed through Intramembranous Ossification?
Bones of the skull and face, mandible, flat portion of the clavicle.
p.43
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the five cell types in bone tissue?
Osteoprogenitor Cells, Osteoblasts, Osteocytes, Bone Lining Cells, Osteoclasts.
p.7
Components and Organization of Bone
What occupies the spaces within the meshwork of spongy bone?
Marrow and blood vessels.
p.2
Structure and Function of the Epiphyseal Plate
What is the role of the epiphyseal plate in bone growth?
It allows for the lengthening of bones during growth.
p.66
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What occurs to the cartilage matrix during the process of hypertrophy?
It becomes thin and irregular between large cells.
p.28
Components and Organization of Bone
What does the arrangement of collagen fibers provide to the osteons?
It provides strength to the osteons.
p.63
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What happens to the perichondrium after the cartilage model is fully established?
It stops producing chondrocytes and instead forms osteoblasts.
p.21
Types of Bone Tissue: Mature vs. Immature Bone
What is interstitial lamella?
It is the remnants of old osteons found between newer osteons in mature bone.
p.21
Types of Bone Tissue: Mature vs. Immature Bone
What characterizes mature compact bone?
It is dense and forms the outer layer of bones, providing strength and support.
p.32
Components and Organization of Bone
What surrounds Volkmann’s Canals?
They are not surrounded by concentric lamellae.
p.4
Components and Organization of Bone
What are the main components of bone?
Bone is primarily composed of organic matrix, inorganic minerals, and water.
p.80
Components and Organization of Bone
What is osteoid?
The unmineralized organic component of bone matrix.
p.79
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the relationship between new cartilage production and resorption at the epiphyseal plate?
The amount of new cartilage produced equals the amount resorbed.
p.38
Components and Organization of Bone
What is a key feature of mature spongy bone regarding marrow spaces?
Numerous marrow spaces of various sizes are present.
p.16
Periosteum and Endosteum: Structure and Function
Where do Sharpey's fibers extend into?
The outer circumferential and interstitial lamellae, but not into the osteons.
p.12
Structure and Function of the Epiphyseal Plate
What is the Epiphyseal Line?
The remnant of the epiphyseal plate in adults who have stopped growing.
What role do bones play in relation to gravity?
They support the body against gravity and enable movement.
p.7
Components and Organization of Bone
Where is the compact or dense layer of bone found?
Forms the outside of the bone.
p.46
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the characteristics of osteocytes?
Mature bone cells that are non-dividing, completely surrounded by bone matrix, and occupy individual lacunae.
p.7
Components and Organization of Bone
Where is the spongy or cancellous layer located?
Found on the inner aspect of bone.
p.2
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is intramembranous ossification?
A process of bone formation that occurs directly within a membrane.
p.64
Periosteum and Endosteum: Structure and Function
What is the role of the periosteum in endochondral ossification?
It provides a surface for the attachment of muscles and helps in the formation of new bone.
p.1
Types of Bone: Compact, Cancellous, Woven, and Lamellar
What is lamellar bone?
A mature bone that has a regular, organized structure with layers of collagen fibers.
p.62
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What do chondroblasts lay down during endochondral ossification?
A hyaline cartilage model of the future bone.
p.66
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the result of chondrocyte hypertrophy?
Resorption of the cartilage matrix around the large cells.
p.56
Clinical Correlates: Osteoporosis and Osteopetrosis
What treatment may be necessary for severe osteopetrosis?
Hematopoietic stem cell or bone marrow transplant from an allogenic donor.
p.72
Components and Organization of Bone
What is a mixed spicule?
A structure that contains both cartilage and bone components.
p.15
Periosteum and Endosteum: Structure and Function
What are the two layers of the periosteum?
Inner cellular layer and outer fibrous layer.
p.67
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What happens to neighboring lacunae after chondrocyte death?
They become confluent to produce large cavities.
p.51
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the three regions of an actively resorbing osteoclast cell?
Ruffled border, Clear zone (or Sealing zone), and Basolateral zone.
p.30
Components and Organization of Bone
How are canaliculi arranged in relation to the Haversian canal?
They are arranged radially to the Haversian canal.
p.69
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the first site where bone begins to form in the diaphysis of a long bone called?
The primary ossification center.
p.80
Types of Bone: Compact, Cancellous, Woven, and Lamellar
What is woven bone?
A type of bone that is formed quickly and has a haphazard organization of collagen fibers.
p.4
Components and Organization of Bone
What inorganic minerals are primarily found in bone?
The primary inorganic mineral in bone is hydroxyapatite, which contains calcium and phosphate.
p.75
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What are the two types of epiphyseal cartilage?
Proximal epiphyseal cartilage and distal epiphyseal cartilage.
p.16
Periosteum and Endosteum: Structure and Function
What happens to the periosteum where tendons and ligaments attach?
It is subject to stress and can prevent separation or tearing.
p.47
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is an osteocyte?
A mature bone cell that maintains the bone matrix.
p.40
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the five cell types in bone tissue?
Osteoprogenitor cells, osteoblasts, osteocytes, bone lining cells, and osteoclasts.
p.26
Components and Organization of Bone
What do osteons consist of?
Concentric lamellae of bone matrix surrounding a central canal called the osteonal canal.
p.20
Types of Bone Tissue: Mature vs. Immature Bone
What is a lamella?
Plates of collagen fibers cemented by mineralized matrix.
p.11
Types of Bone: Compact, Cancellous, Woven, and Lamellar
Where is compact bone typically found?
In the diaphysis of long bones and the outer layer of other bones.
p.3
Components and Organization of Bone
What characterizes bone tissue?
Mineralized extracellular matrix.
p.1
Types of Bone: Compact, Cancellous, Woven, and Lamellar
What is compact bone?
A dense and strong type of bone that forms the outer layer of bones.
p.49
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
From what do osteoclasts derive?
From the fusion of mononuclear hemopoietic cells (monocyte cell lineage).
p.85
Structure and Function of the Epiphyseal Plate
What invades the Zone of Resorption?
Small blood vessels and osteoprogenitor cells invade the region previously occupied by dying chondrocytes.
p.2
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is a secondary ossification center?
Areas of ossification that appear after the primary center, typically in the epiphyses.
p.2
Bone Growth Mechanisms: Length and Width
How does bone grow in length?
Through the activity at the epiphyseal plate.
p.25
Types of Bone Tissue: Mature vs. Immature Bone
When is Woven Bone typically formed?
During fetal development and in the healing of fractures.
p.72
Components and Organization of Bone
What is a trabecula of cartilage bone?
A small, beam-like structure in bone that is covered by cartilage.
p.15
Periosteum and Endosteum: Structure and Function
What occurs at the attachment points of ligaments and tendons to bone?
The periosteum provides a strong connection.
p.9
Components and Organization of Bone
What are trabeculae?
Structural elements found in spongy bone that form a network.
p.75
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the primary ossification center?
The initial site where ossification begins in endochondral ossification.
p.60
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What happens as more osteoblasts come into apposition with the new bone?
They add more bone matrix.
p.75
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the diaphysis?
The part of the cartilage model that is replaced by bone during ossification.
p.87
Bone Growth Mechanisms: Length and Width
What is laid down to form an osteon during bone growth?
Concentric lamellae of bone.
p.16
Periosteum and Endosteum: Structure and Function
How do collagen fibers of tendons and ligaments interact with bone?
They run obliquely into the bone and merge with the collagen fibers of the extracellular bone matrix.
What is one of the primary functions of bone?
Supports and protects various organs of the body.
p.58
Processes of Bone Formation: Intramembranous and Endochondral Ossification
Where does intramembranous ossification occur within the embryo?
Within the embryonic mesenchyme.
p.58
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What transcription factor is involved in the differentiation of osteoprogenitor cells into osteoblasts?
CBFA1 (Core Binding Factor Alpha - 1).
p.41
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the five cell types found in bone tissue?
Osteoprogenitor Cells, Osteoblasts, Osteocytes, Bone Lining Cells, Osteoclasts.
p.57
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What are the two mechanisms of bone formation?
Intramembranous Ossification and Endochondral Ossification.
p.36
Components and Organization of Bone
What do circumferential lamellae follow?
The entire inner and outer circumferences of the shaft of long bones.
p.49
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the five cell types in bone tissue?
Osteoprogenitor Cells, Osteoblasts, Osteocytes, Bone Lining Cells, and Osteoclasts.
p.57
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What characterizes Endochondral Ossification?
A cartilage model serves as the precursor of the bone.
p.2
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is endochondral ossification?
A process where bone develops by replacing cartilage.
p.49
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
Where are osteoclasts located?
At sites where bone is resorbed.
p.56
Clinical Correlates: Osteoporosis and Osteopetrosis
What therapy is effective in treating osteoporosis?
Hormone replacement therapy (HRT).
p.87
Bone Growth Mechanisms: Length and Width
What is the process by which bone growth in width occurs?
Appositional growth at the bone surface.
p.53
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the Clear Zone or Sealing Zone in osteoclasts?
A ring-like perimeter adjacent to the ruffled border that demarcates the bone area for resorption.
p.59
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What do osteoblasts secrete during intramembranous ossification?
Type I collagen and matrix proteins, known as osteoid.
p.59
Processes of Bone Formation: Intramembranous and Endochondral Ossification
Are lamellae present in the early stage of osteoid formation?
No, lamellae are not present at this stage.
p.38
Components and Organization of Bone
How is the tissue arranged in mature spongy bone?
As trabeculae or spicules.
p.44
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What role do osteoblasts play in bone remodeling?
They are involved in the formation of new bone tissue during the remodeling process.
p.47
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are canaliculi?
Microscopic channels that connect lacunae and allow communication between osteocytes.
p.18
Periosteum and Endosteum: Structure and Function
What type of bone is lined by endosteum within the marrow cavity?
Trabeculae of spongy bone.
p.42
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the five cell types in bone tissue?
Osteoprogenitor Cells, Osteoblasts, Osteocytes, Bone Lining Cells, Osteoclasts.
p.36
Components and Organization of Bone
What are the main components of mature compact bone structure?
Osteons, Haversian canals, Volkmann’s canals, interstitial lamellae, and circumferential lamellae.
p.36
Components and Organization of Bone
What are Haversian canals?
Canals that run through the osteons, containing blood vessels and nerves.
p.57
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What are examples of bones formed through Endochondral Ossification?
Long bones, vertebrae, pelvis.
p.7
Components and Organization of Bone
What are trabeculae?
Thin anastomosing spicules of bone tissue.
p.1
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the Haversian system?
Another term for the osteon, referring to the system of canals and surrounding bone matrix in compact bone.
p.55
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the ruffled border of osteoclasts?
A specialized structure that increases the surface area for bone resorption.
p.52
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the function of the increased surface area in the ruffled border?
To facilitate the release of hydrolytic enzymes and endocytosis of degraded bone debris.
p.40
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are osteoprogenitor cells derived from?
Mesenchymal stem cells in the bone marrow.
p.12
Structure and Function of the Epiphyseal Plate
What is the Epiphyseal Plate?
A hyaline cartilage plate in the metaphysis at each end of a long bone, found in children and adolescents.
p.4
Components and Organization of Bone
What is the significance of collagen in bone?
Collagen provides tensile strength and flexibility to the bone.
p.82
Structure and Function of the Epiphyseal Plate
What occurs in the resting zone of the growth plate?
Chondrocytes are relatively inactive and serve as a reserve for future growth.
p.11
Types of Bone: Compact, Cancellous, Woven, and Lamellar
What is the primary function of compact bone?
To provide strength and support to the skeletal structure.
p.76
Processes of Bone Formation: Intramembranous and Endochondral Ossification
When does the secondary ossification center in the distal epiphyseal cartilage develop?
At a later time point after the proximal center.
p.77
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What are secondary ossification centers?
Areas in bones where ossification occurs after primary ossification, typically in the epiphyses.
p.19
Components and Organization of Bone
What happens to red marrow in mature adults?
It gets replaced with fat cells and is known as yellow marrow.
p.38
Components and Organization of Bone
How do osteocytes, lacunae, and canaliculi in mature spongy bone compare to those in mature compact bone?
They resemble those of mature compact bone but are arranged differently.
p.7
Components and Organization of Bone
What are the two distinct structural arrangements of bone tissue?
Compact (dense) layer and spongy (cancellous) layer.
p.19
Components and Organization of Bone
Under what condition can yellow marrow revert to red marrow?
When stimulated, such as during extreme blood loss.
p.14
Periosteum and Endosteum: Structure and Function
What are the components of the periosteum in an actively growing bone?
An outer fibrous layer of dense connective tissue, vessels, and nerves, and an inner cellular layer of osteoprogenitor cells.
p.14
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are periosteal cells?
Cells present in the inner cellular layer of the periosteum that can divide to become osteoblasts when stimulated.
p.46
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What do osteocytes use to communicate with distant cells?
Signaling molecules such as nitric oxide.
p.46
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the function of the long cell processes of osteocytes?
They extend into canaliculi to facilitate communication.
p.66
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What should matrix calcification not be confused with?
Bone matrix mineralization.
p.86
Structure and Function of the Epiphyseal Plate
What occurs at the epiphyseal end while spongy bone is formed at the diaphyseal side?
New cartilage matrix is formed to maintain the thickness of the epiphyseal plate.
p.83
Structure and Function of the Epiphyseal Plate
How do chondrocytes in the Zone of Proliferation compare to those in the Resting Zone?
Chondrocytes are larger than those in the reserve zone.
p.83
Structure and Function of the Epiphyseal Plate
What is the main activity of chondrocytes in the Zone of Proliferation?
They divide and get organized into distinct columns.
p.76
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What develops shortly after birth in endochondral ossification?
A secondary ossification center in the proximal epiphyseal cartilage.
p.76
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What causes the development of the secondary ossification center?
Hypertrophy, degeneration, and calcification of the epiphyseal cartilage.
p.82
Structure and Function of the Epiphyseal Plate
What are the main zones in the growth plate?
The zones include the resting zone, proliferative zone, hypertrophic zone, and ossification zone.
p.12
Structure and Function of the Epiphyseal Plate
In which age group is the Epiphyseal Plate found?
In children and adolescents.
p.48
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the two types of Bone Lining Cells?
Periosteal Cells and Endosteal Cells.
p.77
Structure and Function of the Epiphyseal Plate
What is the epiphyseal plate?
A growth plate that allows for the lengthening of bones during development.
p.77
Components and Organization of Bone
What is the function of articular cartilage?
To provide a smooth, lubricated surface for joint movement and to absorb shock.
p.36
Components and Organization of Bone
What are interstitial lamellae?
Remnants of previous concentric lamellae located between osteons.
p.46
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is a lacuna?
A space in the bone matrix where the osteocyte is located.
p.2
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are the four types of bone cells?
Osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts.
p.36
Components and Organization of Bone
What are Volkmann’s canals?
Canals that connect Haversian canals and allow for communication between them.
p.3
Components and Organization of Bone
In what form is calcium phosphate deposited in bone tissue?
As hydroxyapatite crystals (Ca10(PO4)6(OH)2).
p.49
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is a resorption bay?
A shallow bay where osteoclasts rest directly on bone tissue during resorption.
p.66
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is established during endochondral ossification?
The periosteal bony collar.
p.52
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What processes are enhanced by the ruffled border of osteoclasts?
Release of hydrolytic enzymes and endocytosis.
p.9
Components and Organization of Bone
What is the composition of trabecular bone?
It consists of a lattice of trabeculae and contains red bone marrow.
p.12
Structure and Function of the Epiphyseal Plate
What happens to the Epiphyseal Plate in adults?
It is replaced by the epiphyseal line once growth has stopped.
p.26
Components and Organization of Bone
What are the main structural components of mature compact bone?
Osteons (Haversian Systems), Haversian Canals, Volkmann’s Canals, Interstitial Lamellae, Circumferential Lamellae.
p.20
Types of Bone Tissue: Mature vs. Immature Bone
What are the two types of bone tissue?
Mature Bone and Immature Bone.
p.39
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the function of red marrow?
It is responsible for the production of blood cells.
p.82
Structure and Function of the Epiphyseal Plate
What is the role of the ossification zone in the growth plate?
It is where cartilage is replaced by bone tissue.
p.26
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What types of cells are found in the endosteum lining the Haversian canals?
Osteoprogenitor and endosteal cells.
p.64
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What is the first stage of endochondral ossification?
Formation of cartilage models of developing bone.
p.3
Components and Organization of Bone
What are the components of a bone?
Bone tissue and other connective tissues such as hemopoietic tissue, fat tissue, blood vessels, nerves, and cartilage.
p.43
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What do osteoblasts secrete to aid in mineralization?
Small membrane-bound matrix vesicles containing alkaline phosphatase (ALP).
p.56
Clinical Correlates: Osteoporosis and Osteopetrosis
What is the normal balance in bone health?
Bone resorption by osteoclasts and bone formation by osteoblasts.
p.56
Clinical Correlates: Osteoporosis and Osteopetrosis
What is defective in osteopetrosis regarding bone remodeling?
The remodeling of woven bone to compact bone.
p.44
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What is the origin of osteoblasts?
They originate from osteoprogenitor cells.
p.39
Components and Organization of Bone
What is a trabecula?
A small rod or beam of bone tissue that forms the structural framework of spongy bone.
p.20
Types of Bone Tissue: Mature vs. Immature Bone
What components make up Mature Bone?
Osteons (Haversian systems), interstitial lamellae, and circumferential lamellae.
How can calcium and phosphate be utilized by the body?
They can be mobilized from the bone matrix and taken up by the blood as needed.
p.77
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What role do secondary ossification centers play in bone development?
They contribute to the formation of the epiphyses and the overall shape of the bone.
p.41
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
How does the nucleus of Osteoprogenitor Cells appear?
Lightly staining with an elongate or ovoid shape.
p.49
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
What are osteoclasts?
Large, multinucleated cells involved in bone resorption.
p.62
Processes of Bone Formation: Intramembranous and Endochondral Ossification
When does endochondral ossification begin?
At the 8th week of gestation.
p.62
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What occurs at the site of future bone during endochondral ossification?
Proliferation and aggregation of mesenchymal cells.
p.85
Structure and Function of the Epiphyseal Plate
What do osteoprogenitor cells differentiate into in the Zone of Resorption?
They differentiate into osteoblasts.
p.2
Bone Growth Mechanisms: Length and Width
How does bone grow in width?
Through appositional growth, where new bone is added to the outer surface.
p.58
Processes of Bone Formation: Intramembranous and Endochondral Ossification
What happens to mesenchymal cells during intramembranous ossification?
They migrate and aggregate in specific areas, forming ossification centers.
p.39
Components and Organization of Bone
What is an osteon?
The basic structural unit of compact bone, consisting of a central canal surrounded by concentric rings of bone matrix.
p.20
Types of Bone Tissue: Mature vs. Immature Bone
How do mature compact bone and mature spongy bone differ in structure?
Both have the same lamellar structure, but spongy bone is arranged as trabeculae or spicules.
p.41
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
Where are Osteoprogenitor Cells located?
In the inner cellular layer of the periosteum and the endosteal lining of Haversian canal, Volkman’s canal, and marrow cavities.
p.39
Types of Bone: Compact, Cancellous, Woven, and Lamellar
What characterizes mature spongy bone?
It has a porous structure that provides strength while minimizing weight.
p.85
Structure and Function of the Epiphyseal Plate
What happens in the Zone of Calcified Cartilage?
The cartilage matrix gets calcified, hypertrophied cells degenerate, and calcified cartilage serves as a scaffold for new bone deposition.
p.85
Structure and Function of the Epiphyseal Plate
What characterizes the Zone of Resorption?
It is near the diaphysis where calcified cartilage is in direct contact with the connective tissue of the marrow cavity.
p.7
Components and Organization of Bone
What does the spongy bone consist of?
A sponge-like meshwork of trabeculae.
p.43
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
When are matrix vesicles secreted by osteoblasts?
Only when the matrix is produced, making it a regulated process.
p.43
Bone Cells: Osteoprogenitor Cells, Osteoblasts, Osteocytes, and Osteoclasts
How can osteoblasts be identified in tissue?
When arranged as a single layer of cells in apposition to newly forming bone.
