Skeletal Tissue: Histology Flashcards
These establish the segmental organization of the body, including the vertebral column, the occipital bone of the skull, involuntary musculature of the neck, body wall and limbs
Somites
Loosely organized tissue formed from the sclerotome of somites (mesoderm)
Mesenchyme
Mesenchyme is loosely organized tissue formed from this
The sclerotome of somites (mesoderm)
Vertebrae form from this
Sclerotome of the somites
Somites are derived from this
Paraxial mesoderm
During this week in development, sclerotome cells migrate around the spinal cord and notochord to merge with cells from the opposing somite on the other side of the neural tube
4th week
Sclerotomes will develop into this
Vertebrae
The ventral portion of the sclerotome surrounds the notochord forming this
Vertebral body
The dorsal part of the sclerotome flanks the neural tube and will eventually expand to form this
Vertebral arch
Which portion of the sclerotome (dorsal or ventral) will form the vertebral body?
Ventral
Surrounds the notochord
Which portion of the sclerotome (dorsal or ventral) will form the vertebral arch?
Dorsal
Flanks the neural tube
The dermomyotome contributes to these 2 parts of the body
Dermis of the skin throughout the trunk
Myotome
This contributes to the dermis of the skin throughout the trunk and forms the myotome
Dermomyotome
This gives rise to the epaxial (dorsal) and hypaxial (ventrolateral) muscles of the body wall
Myotome
Word that describes the dorsal muscles of the body mall
Epaxial
Word that describes the ventrolateral muscles of the body wall
Hypaxial
These cells migrate into the developing limbs to form the limb muscles
Myotome cells
The division between the cranial and caudal portions of each sclerotome is characterized by a line of transversely arranged cells known as the intrasegmental boundary, otherwise known as this
Von Ebner’s fissure
What is Von Ebner’s fissure?
The division between the cranial and caudal portions of each sclerotome
Avascular, connective tissue that consists of a matrix and chondrocytes
Cartilage
Is cartilage vascularized?
No
What are the three types of cartilage?
Hyaline
Elastic
Fibro-
2 components of basic cartilage
Matrix and chondrocytes
Type of cartilage that has a lubricated, glassy appearance in the living person and has three types of molecules that make up the cartilaginous matrix (collagen, proteoglycans, multi-adhesive glycoproteins)
Hyaline cartilage
What is the predominant type of collagen in hyaline cartilage?
Type II
(IX, XI, and X also present)
This is the most important monomer in hyaline cartilage, and has a large negative charge and affinity for water molecules
Aggrecan
Aggregan is the most important monomer in this type of cartilage
Hyaline cartilage
What is the charge of aggrecan?
Large negative charge
has an affinity for water molecules
This has clinical value as markers of cartilage turnover and degeneration
Multi-adhesive glycoproteins
Most of hyaline cartilage is made up of this due to increased hydration of the matrix and much of it is attached to the aggrecan monomer
Intercellular water
These influence chondrocyte integration with the matrix and provides an important marker for cartilage degeneration
Multi-adhesive glycoproteins
Internal modeling relies on the ability of these to detect changes in composition
Chondrocytes
Describes when chondrocytes are distributed in clusters in cartilage
Isogenous groups
Isogenous groups produce this, while dispersing themselves away from one another
The collagenous matrix
Also produce and maintain the ECM
3 components of the hyaline cartilage matrix
Capsular (pericellular)
Territorial
Interterritorial
Component of hyaline cartilage matrix that is densely staining immediately around chrondrocyte (high concentration of matrix components)
Capsular (pericellular) matrix
Component of hyaline cartilage matrix that surrounds isogenous groups
Territorial matrix
Component of hyaline cartilage matrix that contains arranged network of type II collagen fibrils with smaller concentrations of matrix components
Territorial matrix
Component of hyaline cartilage matrix that surrounds territorial matrix and occupies space between groups of chondrocytes
Interterritorial matrix
Territorial matrix surrounds isogenous groups and contains arranged network of these with smaller concentrations of matrix components
Type II collagen
This provides a model for the developing skeleton of the fetus and is a precursor for bones by the process of endochondral ossification
Hyaline cartilage
Where does hyaline cartilage exist in the adult?
Trachea, bronchi, larynx, nose
Dense connective tissue composed of cells that are indistinguishable from fibroblasts
Perichondrium
This serves as the source of new cartilage cells
Perichondrium
The perichondrium serves as the source of these
New cartilage cells
This underlies the perichondrium and represents deposition of new cartilage on the surface of the existing hyaline cartilage (appositional growth)
Growing cartilage
This contains chondroblasts and immature chondrocytes that are little more than nucleus in the lacuna
Growing cartilage
Growing cartilage underlies this
The perichondrium
Type of growth where new growth deposits on the surface of existing hyaline cartilage
Appositional growth
Type of growth when new cartilage forms by chondrocyte mitosis in existing tissue
This is due to chondrocytes retaining the ability to divide
Interstitial growth
Hyaline cartilage of articular joint surfaces of movable joints
Articular cartilage
How is the structure of articular cartilage different from hyaline cartilage?
Articular cartilage has no presence of perichondrium
4 zones of the articular cartilage
Superficial tangential zone
Intermediate transitional zone
Deep radial zone
Calcified zone
Zone of articular cartilage that is pressure resistant
Superficial tangential zone
Zone of articular cartilage that is closest to the articular surface
Superficial tangential zone
Zone of articular cartilage that consists of chondrocytes that are flattened out and surrounded by ECM
Superficial tangential zone
Zone of articular cartilage that is located inferiorly to the superficial tangential zone
Intermediate tangential zone
Zone of articular cartilage that consists of chondrocytes that are rounded out and disorganized collagen fibers
Intermediate tangential zone
Zone of articular cartilage that includes small, round chondrocytes in short columns
Deep radial zone
Zone of articular cartilage where collagen is positioned parallel to the long axis of the bone
Deep radial zone
Zone of articular cartilage that is a calcified matrix with the presence of chondrocytes
Calcified zone
Zone of articular cartilage that is separated by a calcified tidemark line from the deep radial zone
Calcified zone
The deposition of calcium salts in the tissue
Calcification
Type of cartilage that is prone to calcification
Hyaline cartilage
Calcifies as part of the aging process
Describes when calcium and phosphate ions are deposited into a collagen matrix
Mineralization
Elastic cartilage is found in these two parts of the body
Ear (external ear, eustachian tube, walls of the external auditory meatus)
Epiglottis of the larynx
Elastic cartilage does not calcify with aging as hyaline cartilage but is similarly surrounded by this
A perichondrium
Type of cartilage that is made up of hyaline cartilage and dense connective tissue
Fibrocartilage
Is hyaline cartilage surrounded by perichondrium?
Yes
Is elastic cartilage surrounded by perichondrium?
Yes
Is fibrocartilage surrounded by perichondrium?
No
Type of cartilage that is less cartilage matrix material, no surrounding perichondrium, type I and II collagen fibrils
Fibrocartilage
Types of collagen fibrils in fibrocartilage
I and II
Type of cartilage found in the intervertebral discs, some articular surfaces, such as the menisci of the knee joint and the pubic symphysis
Fibrocartilage
What type of cartilage is found in the menisci of the knee joint?
Fibrocartilage
Type of cartilage where chondrocytes are arranged in rows situated between the dense connective tissue
Fibrocartilage
Most cartilage arises from chondroprogenitor mesenchymal tissue that is differentiated into chondroblasts by the expression of this
SOX9
Once these are surrounded by matrix, they are called chondrocytes
Chondroblasts
Once chondroblasts are surrounded by matrix, they are called this
Chondrocytes
These secrete cartilage matrix and move apart as they deposit the matrix
Chondroblasts
This is the most important regulator of calcium and phosphate
Parathyroid hormone
This is the major structural component of bone
Type I collagen
Major structural component of bone that provides compressive strength
Proteoglycan macromolecules
Major structural component of bone that provides attachment to bone substance
Multiadhesive glycoproteins
Major structural component of bone that captures Ca++ and removes apoptotic cells
Bone specific Vitamin K-dependent proteins
Two classifications of bone tissue
Compact (dense) and Spongy (cancellous)
This consists of an outer fibrous layer and inner cellular layer that contains osteoprogenitor cells
Periosteum
The inner cellular layer of periosteum contains this
Osteoprogenitor cells
The periosteum is not present when the articulating surface is covered by this
Cartilage (articular cartilage)
These cells can undergo division and become osteoblasts under the appropriate stimulus
Osteoprogenitor cells
These connect periosteum to underlying bone
Perforating fibers (Sharpey’s fibers)
These are made of collagen and extend into the outer lamellae but not into the osteons
Perforating fibers (Sharpey’s fibers)
What do Perforating fibers (Sharpey’s fibers) connect?
Connect periosteum to underlying bone
What are Perforating fibers (Sharpey’s fibers) made of?
Collagen
This is very thin and covers the small trabeculae of the bony matrix into the marrow cavities
Also contains osteoprogenitor cells, osteoblasts, and bone lining cells in collagen fibers
Endosteum
As an individual ages, red cell formation diminishes and the tissue starts to consist of fat cells, where it is then called this
Yellow marrow
Mature bone is composed of these
Osteons
In mature bone, these consist of concentratic lamellae that surround a central canal
Osteons
In mature bones, oteons consists of concentric lamellae that surround a central canal, called this
Haversian canal
These contain the vascular and nerve supply of the osteon
Haversian canals
Lamellar bone refers to this type of bone
Mature bone
Channels in lamellar bone through which blood vessels and nerves travel from the periosteal and endosteal surfaces to reach Haversian canals and connect these canals to one another
Volkmann’s canals
Volkmann’s canals are channels in this type of bone
Lamellar (mature) bone
A key feature in the histologic identification of Volkmann’s canals is that they are not surrounded by this
Concentric lamellae
These lie between each of the osteons in mature bone and are remnants of past concentric lamellae
Interstitial lamellae
What is the structural difference between mature spongy bone and mature compact bone?
Mature spongy bone has tissue arranged as trabeculae or spicules, with interconnecting marrow spaces
Does mature spongy or mature compact bone have tissue arranged as trabeculae or spicules, with interconnecting marrow spaces?
Mature spongy bone
Type of bone that is unorganized, non lamellar, bundles, more cell bodies, present in fetal and remodeled bone, forming more rapidly
Immature bone
Type of bone in the alveolar sockets of the adult oral cavity
Immature bone
These are where blood vessels pass through bone to meet the marrow
Nutrient foramina
Type of bone that is newly calcified and arranged in an irregular pattern of collagenous fibers and cells
Woven
(aka immature, bundle, primary)
Type of bone found in developing bones and fractures
Woven
(aka immature, bundle, primary)
Bone type that is also called immature, bundle, primary bone
Woven
Where is woven bone type found?
Developing bones and fractures
Bone type that is also called mature or secondary bone
Lamellar
Bone type with bundles of collagen that run in parallel to each other
Is extremely calcified and remodels from woven bone
Lamellar
Bone type found in non-pathological regions of adult bone
Lamellar
Bone type that is also called cortical bone
Compact
Bone type that is most of the lamellar bone and has osteons that are packed tightly
Compact
Bone type found in outer regions of lamellar bones
Compact
Bone type that is also called trabecular, medullary, or spongy bone
Cancellous
Bone types that is the minority of lamellar bone and consists of trabeculae covered with endosteum; or interconnected thin spicules
Cancellous
Bone type found in inner regions of bones
Cancellous
Two types of lamellar bone
Compact and Cancellous
Compact is most of the lamellar bone
Where is compact bone found?
Outer regions of lamellar bones
Where is cancellous bone found?
Inner regions of bones
Osteoprogenitor cells are derived from this
Mesenchymal stem cells in the bone marrow
These cells have been shown to increase osteoblast differentiation in response to electromagnetic pulses
Osteoprogenitor cells
What is osteoid?
Bone matrix
Cells that retain the ability to divide and secrete type I collagen and bone matrix proteins (or osteoid)
Osteoblasts
Cells that lay in apposition to forming bone
Osteoblasts
Unmineralized bone matrix where mineralization is triggered by matrix vesicles
Osteoid
Matrix vesicles trigger mineralization of osteoid, and are rich in this
Alkaline phosphatase
These are rich in alkaline phosphatase and are responsible for the mineralization of bone
Matrix vesicles
Cells that exhibit cytoplasmic processes that allows these cells to communicate
Osteoblasts
These become the canliculi within the matrix, where communication occurs
Cytoplasmic processes of osteoblasts
The cytoplasmic processes of osteoblasts become this, within the matrix
Canaliculi
where these cells communicate with osteoblasts, endothelial cells of bone marrow vasculature, etc.
Mature bone cells that were osteoblasts surrounded by their own matrix
Osteocytes
Cells that reside in lacunae and have long cellular processes that occupy canaliculi
Osteocytes
Cells that have been shown to assist in nutrition of the bone and sensing mechanical stimulation
Osteocytes
What is the lifespan of osteocytes?
10-20 years
Cells that are metabolically active and multifunctional due to responding to mechanical stimuli
Osteocytes
Large cells that have multiple nuclei and specialize in bone resorption
Osteoclasts
Which of the following have multiple nuclei: osteoblasts, osteoclasts, or osteocytes?
Osteoclasts
Osteoclasts are derived from this
Macrophage-monocyte cell lines
This is a resorption bay that depicts the area of bone resorption that is sitting directly under the osteoclast
Howship’s Lacuna
Osteoclasts resorb bone tissue by releasing these 2 things into the constriced microenvironment of the extracellular space
Protons and Lysosomal hydrolases
3 regions of osteoclasts
Ruffled border
Clear zone
Basolateral zone
Area of osteoclast in contact with the bone
Appears as light band on surface near bone
Ruffled border
Area next to ruffled border where bone is being resorbed within the osteoclast
Clear zone
The clear zone of osteoclasts contains these 2 things that are considered the sealing zone between the osteoclast and bone where resorption and degradation occurs
Actin filaments and ECM adhesion molecules
Region of osteoclasts that contains actin filaments and ECM adhesion molecules that are considered the sealing zone between the osteoclast and bone where resorption and degradation occurs
Clear zone
Cell type that has these three regions: ruffled border, clear zone, basolateral zone
Osteoclasts
Region of osteoclasts where exocytosis and fragmentation of the resorbed area occurs
Basolateral zone
Region of osteoclasts that transports vesicles of digested material to cell membrane
Basolateral zone
Bone lining cells are derived from this
Osteoblasts
Cells that function in maintenance and nutrition in non-remodeling bone
Bone lining cells
When present on the periosteum or endosteum, these cells are called periosteal or endosteal cells, respectively
Bone lining cells
