Structure Of Bone Flashcards
What is trabecular bone?
Spongy bone : honeycomb of needle-like or flat pieces called trabeculae.
Two types of bone texture?
Compact and spongy
The dense, external layer of bone.
Which looks smooth and solid to the naked eye.
What is Compact bone ?
Shaft which forms the long axis of the bone.
What is Diaphysis ?
Internal layer of bone.
With honeycomb of small needle-like or flat pieces
What is Spongy bone?
What is the structure of short, irregular and flat bones?
Thin plates of spongy bone covered by compact bone.
Spongy plates are covered inside and outside by CT membranes (periosteum and endostrum).
What is the structure of long bones?
A shaft (diaphysis), bone ends (proximal and distal epiphysis), and membranes (periosteum)
Structure of diaphysis?
A relatively thick collar of compact bone that surrounds a central medullary cavity
Marrow cavity
What is another name for Medullary cavity?
What is Yellow marrow cavity?
Medullary cavity in adults which contains yellow marrow
Bone ends. Broader than the diaphysis.
What is Epiphysis?
Structure of epiphyses?
An outer shell of compact bone forms exterior.
Interior consists of spongy bone.
A thin layer of articular cartilage covers the joint surface of each epiphysis
Between the diaphysis and each epiphysis of an adult long bone.
What is the Epiphyseal line?
What is the metaphysis?
Flared portion of bone where diaphysis and epiphysis meet.
White, double-layer membrane.
Covers external surface of entire bone except joint surfaces.
What is the Periosteum?
Two layers of periosteum?
Outer fibrous layer
Inner osteogenic layer
What is a diploë?
The name of spongy bone found in flat bones
What does the osteogenic layer consist of?
Primarily of Stem cells/osteogenic cells
A disc of hyaline cartilage that grows during childhood to lengthen the bone
What is the Epiphyseal plate?
What is the nutrient foramina?
Openings through which nutrients pass from periosteum to narrow cavity
Tufts of collagen fibers that extend from its fibrous layer into the bone matrix
Secures periosteum to the underlying bone
What are Sharpey’s (perforating) fibers?
What is the endosteum?
A delicate connective tissue membrane which covers internal bone surfaces
What type of tissue does the fibrous layer of periosteum consist of?
Dense irregular connective tissue
Another name for Hematopoietic tissue
What is Red marrow?
Where is red marrow / hematopoietic tissue found?
Within the trabecular cavities of spongy bone of long bones and in diploë of flat bones.
What is the function of bone markings?
Serve as sites of muscle, ligament, tendon attachment
Also joint surfaces or as conduits or blood vessels and nerves
“Within the bone”
What is Endosteum?
The five types of bone tissue cells
Osteogenic cells Osteoblasts Osteocytes Bone-lining cells Osteoclasts
Mitotically active, Bone-forming cells that secrete the bone matrix.
What are Osteoblasts.?
What type of cells do all connective tissue cells originate from? (Except osteoclasts)
What are Mesenchymal cells?
What type of cell is a stem cell?
What are Osteogenic/osteoprogenitor cell
Mitotically active stem cells found in membranous periosteum and endosteum
What are Osteogenic cells/osteoprogenitor cells?
Which type of bone cell plays a role in matrix calcification?
Osteoblasts
Flat cells found on bone surfaces where remodeling is occurring
What is Bone lining cells?
Lamellae that are found just deep to the periosteum and just superficial to the endosteum.
Extending around entire circumference of diaphysis
What are Circumferential Lamellae?
Structural unit of compact bone
What is Osteon/Haversian system?
Spidery-shaped, Mature bone cell that monitors and maintains the mineralized bone matrix
What are Osteocytes?
What are tiny weight-bearing pillars?
Osteons
“Little plate”
Lamella
Type of bone cell that is responsible for bone growth
What are Osteoblasts?
What is a lamella?
A group of hollow tubes of bone matrix, one placed outside the next like growth rings on a tree trunk.
Lamellar bone is more commonly known as ….?
Compact bone
Giant multinucleate cells located at sites of bone resorption
What are Osteoclasts?
Collagen fibers on a lamella run in similar direction or opposite directions?
Opposite
Canal running through the center of each osteon
What is the Central canal/Haversian canal?
“Little lakes” where osteocytes lie
What are Lacunae?
What are canaliculi?
Hairlike canals that connect the lacunae to each other and to the central canal
Canals which lie at right angles to the long axis to the bone and connect the blood and nerve supply of the medullary cavity to the central canal.
What are Perforating canals/Volkmann’s canals?
How are canaliculi formed?
When bone is forming, osteoblasts that are secreting bone matrix surround blood vessels and maintain contact with one another by tentacle-like projections.
The newly secreted matrix hardens
Maturing cells become trapped
Tiny canals are formed
Lamellae that are not part of complete osteons.
Lie between intact osteons
What are Interstitial lamellae?
Type of bone that is only a few cells thick
Irregularly arranged Lamellae
Osteocytes are interconnected by canaliculi
What is spongy bone?
How do nutrients reach osteocytes of spongy bone?
By diffusing through the canaliculi from capillaries in the endosteum surrounding the trabeculae.
Substances that include bone cells and an osteoid
What are organic components?
This makes up approx. one-third of the matrix
Includes ground substance and collagen fibers
What is an osteoid?
Substances : mineral salts
What are inorganic components?
What is bone ground substance composed of?
Proteogylcans
Glycoproteins
These bonds stretch and break easily on impact, dissipating energy to prevent the force from rising to a fraction value.
Most of these bonds re-form.
What is sacrificial bonds?
Why do bones last long after death?
Because of the mineral salts they contain, providing an enduring “monument”.
