Lab Quiz 4 & 5 Material Flashcards
What key feature distinguishes bone from the other connective tissues?
Its mineralized matrix
What is the purpose of bone’s mineralized matrix? List 2 functions.
Support & protection
The mineral is calcium phosphate in the form of {…} crystals.
Hydroxyapatite
By virtue of its mineral content, bone also serves as a storage site for these 2 ions.
What are calcium & phosphate?
Which 2 major collagen molecules are found in bone? Which is more prominent as a major structural component?
Type I (more prominent) and Type V
NOTE: Type I Collagen is, in fact, the most prominent structural component of bone!
PROTEOGLYCAN macromolecules contain a core protein with various numbers of covalently attached side chains of {…}.
Glycosaminoglycans
Some proteoglycans, such as keratan sulfate, contain {…}, a bone-specific protein that strongly binds to hydroxyapatite crystals.
Osteoadherin
This multiadhesive glycoprotein serves as a glue between the collagen and hydroxyapatite crystals.
What is osteonectin?
This multiadhesive glycoprotein is produced exclusively by osteocytes in response to mechanical stress.
What is podoplanin (E11)?
This multiadhesive glycoprotein is critical for bone matrix mineralization.
What is the dentin matrix protein (DMP)?
These multiadhesive glycoproteins, called BONE SIALOPROTEINS, are responsible for mediating the attachment of cells to the bone matrix and initiating calcium phosphate formation during the mineralization process, respectively.
What are BSP-1 (osteopontin) and BSP-2?
BONE-SPECIFIC, VITAMIN K-DEPENDENT PROTEINS serve a variety of functions and include {…}, which captures calcium from the circulation and attracts and stimulates osteoclasts in bone remodeling; protein {…} (single letter), which assists in the removal of cells undergoing apoptosis; and {…} (MGP), which participates in the development of vascular calcifications.
1) Osteocalcin
2) S
3) Matrix Gla-protein
This is a duo of small regulatory proteins, such as BONE MORPHOGENIC PROTEINS (BMPs), SCLEROSTIN (a BMP antagonist), and INTERLEUKINS (IL-1, IL-6).
What are growth factors and cytokines?
Recombinant human {…}, also known as {…} (OP-1), is now used clinically to induce bone growth after bone surgery involving large bone defects, spinal fusions, or implantation of graft materials.
1) BMP-7
2) Osteogenic protein-1
Within the bone matrix are spaces called {…}, each containing a bone cell, or {…}. The osteocyte extends numerous processes into small tunnels called {…}, which course through the mineralized matrix, connecting adjacent lacunae and allowing contact between the cell processes of neighboring osteocytes.
1) Lacunae
2) Osteocyte
3) Canaliculi
These bone cells are derived from mesenchymal stem cells; they give rise to osteoblasts.
What are osteoprogenitor cells?
These bone cells secrete the extracellular matrix of bone; once the cell is surrounded by its secreted matrix, it is called an OSTEOCYTE.
What are osteoblasts?
These bone cells remain on the bone surface when there is no active growth. They are derived from those osteoblasts that remain after bone deposition ceases.
What are bone-lining cells?
These bone cells resorb bone and are present on bone surfaces where bone is being removed or remodeled (reorganized) or where bone has been damaged.
What are osteoclasts?
The principal organs of the musculoskeletal system.
What are bones?
The structural component of bones.
What is bony tissue?
This class of bones is longer in one dimension than other bones and consists of a shaft and two ends (e.g., the tibia and the metacarpals).
What are long bones?
This class of bones is nearly equal in length and diameter (e.g., the carpal bones of the hand).
What are short bones?
This class of bones is thin and plate-like (e.g., the bones of the calvaria [skullcap], scapula, and sternum) and is composed of a layer of spongy bone sandwiched between two layers of thick, compact bone.
What are flat bones?
This class of bones has a shape that does not fit into any one of the three groups just described; the shape may be complex (e.g., a vertebra), or the bone may contain air spaces or sinuses (e.g., the ethmoid bone).
What are irregular bones?
Long bones have a shaft, called the {…}, and two expanded ends, each called an {…}.
1) Diaphysis
2) Epiphysis
The flared portion of the bone between the diaphysis and the epiphysis is called the {…}. It extends from the diaphysis to the {…} line.
1) Metaphysis
2) Epiphyseal
The large cavity filled with bone marrow that forms the inner portion of the bone.
What is the medullary cavity?
The fibrous connective tissue capsule covers the outer surface of the bone.
What is the periosteum?
If the bone forms a freely movable joint (also called a {…} joint), the contact areas of the two bones are referred to as articular surfaces.
Synovial
The articular surfaces are covered by hyaline cartilage, also called {…} cartilage, because of its location and function.
Articular
Simple trauma to a joint by a single incident or by repeated insult can damage the articular cartilage, causing it to calcify. Eventually, the cartilage is replaced by bone. This process can lead to {…} (i.e., bony fusion in the joint and subsequent loss of motion).
Ankylosis
Inflammation of the joints.
What is arthritis?
This type of arthritis is caused by the deposition of uric acid crystals in the joints, particularly those of the toes and fingers.
What is gouty arthritis (gout)?
The {…} capsule that surrounds the joint cavity is composed of an outer fibrous layer of dense irregular connective tissue and inner layer of {…} membrane that is attached to the edges of {…} cartilages.
1) Articular
2) Synovial
3) Articular
Aside from movable joints, what are 2 other types of joints?
Slightly moveable & immovable
The surgical replacement of joints due to {…}, the most frequent idiopathic disease of joints characterized by degeneration of articular cartilage, is called an {…}. During this procedure, the damaged articular surface with underlying bone tissue is removed and replaced with an artificial joint (called a {…}) made of metal, plastic, or ceramic materials designed to mimic the normal anatomic structures of the joint.
1) Osteoarthritis
2) Arthroplasty
3) Prosthesis
Which areas will you not find bone covered by a periosteum?
Areas where bones articulate
The periosteum that covers an actively growing bone consists of an outer fibrous layer that resembles these tissues.
What are dense, irregular connective tissues?
The inner, more cellular layer in contact with bone contains skeletal {…} cells, including osteoprogenitor cells.
Stem
What is the main component (fibrous OR cellular layer) of the periosteum when active bone formation is not in progress on the bone surface?
Fibrous layer
Which layer is underdeveloped when there is no active bone formation on the bone surface? Fibrous or cellular?
Cellular layer
These are the relatively few cells in the INNER CELLULAR LAYER present when active bone formation is not in progress on the bone surface. These cells can undergo division and become osteoblasts under the appropriate stimulus.
What are periosteal cells?
A 90-kDa extracellular matrix protein secreted by periosteal cells that is a key regulator of periosteal responses to mechanical stress, injury, and bone repair.
What is periostin?
Collagen fibers from these structures extend obliquely or at right angles to the long axis of the bone, where they are continuous with the collagen fibers of the extracellular matrix. These fibers are called {…} or {…} fibers. They extend into the outer circumferential and interstitial lamellae but usually do not enter the osteons.
1) Perforating
2) Sharpey
The lining tissue of both the compact bone facing the marrow cavity and the trabeculae of spongy bone within the cavity is referred to as {…}, a layer of connective tissue that contains {…} cells.
1) Endosteum
2) Osteoprogenitor
OSTEOPROGENITOR and BONE-LINING CELLS are difficult to distinguish at the microscopic level. They are both flattened in shape with elongated nuclei and indistinguishable cytoplasmic features. Because of their location within the bone cavities, they are frequently called this type of cell.
What is endosteal?
This type of bone marrow consists of blood cells in different stages of development and a network of reticular cells and fibers that serve as a supporting framework for the developing blood cells and vessels.
What is red bone marrow?
This type of marrow consists mainly of fat cells.
What is yellow marrow?
What are the two distinct structural arrangements (i.e., classifications) of bone tissue?
1) Compact (dense)
2) Spongy (cancellous)
The thin, anastomosing spicules of bone tissue that make up the sponge-like meshwork of spongy bone.
What are trabeculae?
Mature bone is largely composed of cylindrical units called {…} or {…} systems. The osteons consist of concentric {…} of bone matrix surrounding a central canal, the {…} (Haversian) canal, which contains the vascular and nerve supply of the
osteon.
1) Osteons
2) Haversian
3) Lamellae
4) Osteonal
Between the osteons are remnants of previous concentric lamellae called {…} lamellae.
Interstitial
The term for the mature bone of Haversian systems.
What is lamellar bone?
This type of lamellae follows the entire inner and outer circumferences of the shaft of a long bone, appearing much like the growth rings of a tree.
What are circumferential lamellae?
These are channels in lamellar bone through which blood vessels and nerves travel from the periosteal and endosteal surfaces to reach the osteonal (Haversian) canal; they also connect osteonal canals to one another.
What are perforating (Volkmann) canals?
These are openings in the bone through which blood vessels pass to reach the marrow.
What are nutrient foramina?
Where in a long bone will you find the greatest numbers of nutrient foramina? List 2 structures/areas.
Diaphysis & epiphysis
The nutrient arteries that supply the diaphysis and epiphysis arise developmentally as the principal vessels of the {…} buds.
Periosteal
Bone tissue initially formed in the skeleton of a developing fetus.
What is immature bone?
Immature bone does not display an organized lamellated appearance. On the basis of its collagen fiber arrangement, such bone is referred to as this.
What is nonlamellar?
List 2 other names for nonlamellar bone.
Bundle or woven bone
True or False: Immature bone forms more rapidly than mature bone.
True
The process of new bone formation.
Osteogenesis
Osteogenesis requires a population of renewable {…} cells (osteoblast precursor cells) that are responsive to molecular stimuli that transform them into bone-forming cells.
Osteoprogenitor
The key factor that triggers the differentiation of osteoprogenitor cells is a transcription factor called {…} (CBFA1), also called {…} (RUNX2).
1) Core binding factor alpha-1
2) Runt-related transcription factor 2
Several clinical studies have demonstrated that {…} (PEMF) stimulation assists in the healing of bone fractures by increasing bone tissue regeneration.
Pulsed electromagnetic field
Morphologically, osteoprogenitor cells resemble the {…} cells that form the innermost layer of the periosteum and the {…} cells that line the marrow cavities, the osteonal (Haversian) canals, and the perforating (Volkmann) canals.
1) Periosteal
2) Endosteal
The initial unmineralized bone.
HINT: Bone-like
What is an osteoid?
What 2 components constitute the osteoid?
Type I collagen & bone matrix proteins
Bone matrix proteins produced by the osteoblast include {…} proteins, such as osteocalcin and osteonectin; {…} glycoproteins, such as bone sialoproteins (BSP-1 [osteopontin] and BSP-2); thrombospondins; various {…} and their aggregates; and {…} (TNAP).
1) Calcium-binding
2) Multiadhesive
3) Proteoglycans
4) Tissue nonspecific alkaline phosphatase
The osteoblast is also responsible for the calcification of bone matrix. The calcification process appears to be initiated by the osteoblast through the secretion into the matrix of these small, 50- to 250-nm, membrane-limited sacs.
What are matrix vesicles?
Is the cytoplasm of an ACTIVE OSTEOCYTE acidophilic or basophilic?
Basophilic
In contrast to the secreting osteoblasts found in active matrix deposition, {…} osteoblasts are flat or attenuated cells that cover the bone surface. These cells resemble osteoprogenitor cells.
Inactive
How are osteoblast processes able to communicate with other osteoblasts and osteocytes?
Via gap junctions
The mature bone cell enclosed by bone matrix that was previously secreted as an osteoblast.
What is an osteocyte?
Osteocytes’ cytoplasmic processes are enclosed by {…} within the matrix.
Canaliculi
In addition to typical cell-to-cell communication (i.e., gap junctions), osteocyte processes contain {…} (the unopposed half of gap junction channels) that provide communication between cells and the extracellular matrix.
Hemichannels
Recent discoveries show that osteocytes are metabolically active and multifunctional cells. They are involved in the process of {…}, in which they respond to mechanical forces applied to the bone.
Mechanotransduction
The movement of interstitial fluid through the canalicular system generates this type of potential at the moment when stress is applied.
What is transient electrical (streaming) potential?
The streaming potential opens {…} calcium channels in the membranes of the osteocytes over which the tissue fluid flows.
Voltage-gated
The shear stress of the fluid flow also induces the opening of {…} that allow the release of accumulated intracellular molecules into the extracellular space of the canaliculi.
Hemichannels
An osteocyte responds to reduced mechanical stress by secreting enzymes called {…} (MMPs).
Matrix metalloproteinases
The reversible remodeling of the pericanalicular and perilacunar bone matrix induced by osteocytes under increased mechanical stress.
What is osteocytic remodeling?
