Bones And Skeletal Tissue - Chapter 6 Flashcards
What type of connective tissue is perichondrium composed of?
Dense irregular connective tissue
What type of cartilage growth involves cartilage-forming cells in the surrounding perichondrium secreting new matrix against the external face of the existing cartilage tissue?
Appositional growth
What type of cartilage growth involves lacunae-bound chondrocytes dividing and secreting new matrix, expanding the cartilage from within? When does this type of growth typically end?
Interstitial growth; typically ends during adolescence when the skeleton stops growing
What are the seven major functions of bones?
- Protection for organs, 2. Support for the body, 3. Anchorage for skeletal muscles for movement, 4. Hematopoiesis, 5. Mineral storage, 6. Triglyceride storage, and 7. Osteocalcin production
What does osteocalcin, the hormone produced by bone cells, help regulate? What does it bind?
Insulin secretion (glucose metabolism in the pancreas), calcification, testosterone synthesis, energy expenditure; it binds calcium
Where is hyaline cartilage found on the skeleton?
Articulate surfaces of long bones, costal cartilage of the ribs, and nasal cartilages
Where is elastic cartilage found on the skeleton?
Nose, external ear, epiglottis
Where is fibrocartilage found on the skeleton?
Intervertebral discs and symphyses
What is the connective tissue that envelopes cartilage where it is not at a joint?
Perichondrium
How does cartilage proliferate at epiphyseal growth plates for longitudinal bone growth?
Interstitial growth
Spongy bone is a honeycomb of small, needle-like or flat pieces called ___________.
Trabeculae
Compact bone is covered outside and inside by connective tissue membranes: __________ and __________, respectively.
Periosteum; endosteum
What are the three components that all long bones have?
Epiphyses, diaphyses, and membranes
What lies between the epiphysis and diaphysis?
Epiphyseal plate (or line, if no longer growing)
What does the endosteum line in a long bone?
The inside of the medullary cavity
What kind of marrow is found in the medullary cavity of an adult long bone?
Yellow marrow
What is the flared portion of a long bone, where the diaphysis and epiphysis meet? (Not the epiphyseal line)
Metaphysis
What secures the periosteum to the external surface of the bone?
Bundles of collagen fibers called “perforating fibers”
The periosteum has two layers, the outer _______ _______, made of _______ _______ connective tissue, and the inner _______ _______, which contains ______________ cells, ________, and _________.
Fibrous layer; dense irregular; osteogenic layer; osteoprogenitor; osteoclasts, and osteoblasts
What membrane covers the trabeculae of spongy bone and lines the canals that pass through compact bone?
Endosteum
Where is red marrow found in infants? Adults?
In infants, it is found in the medullary cavities of long bones and in spongy bone. In adults, it is found only in the spongy bone of the femur and humerus, flat bones and irregular bones.
What bone component can revert back to a prior form if a person becomes anemic?
Yellow marrow in adult long bones can revert back to red marrow if increased hematopoiesis is needed.
Where are marrow transplants and extractions typically done? Why?
In flat and irregular bones, especially the pelvis, because red marrow is much more active there
Red marrow is found in the _____ of flat bones, such as the sternum.
Diploe
What is a diploe?
A layer of spongy bone within a flat bone, like the sternum or cranium
The structural units of compact bone are ______.
Osteons
Osteons consist of tree-like rings called _______, which contain ________, and a central ___________ ______.
Lamellae; lacunae; Haversian canal
What tiny canals allow osteocytes to communicate with each other and transmit nutrients and wastes?
Canaliculi
What are osteoprogenitor cells and where are they found?
Stem cells that are also called osteogenic cells, they are mitotically active and found in the periosteum and endosteum. They appear flattened in growing bones.
Which bone cells are cuboidal in shape when actively mitotic and secrete osteoid?
Osteoblasts
Where are osteoblasts found?
In the periosteum
Where are osteoclasts found?
In the endosteum
Which bone cells are giant, multinucleated, macrophage-type cells that reside in resorption bays and directly contact bone via their ruffled border?
Osteoclasts
Initial bone is _____________ and contains 90% ________ and 10% _____-_______ _____.
Unmineralized; collagen; calcium-binding proteins.
Which bone cells respond to increased mechanical stress? What cells do they communicate this to? What do these cells do when they receive the message?
Osteocytes; osteoblasts and osteoclasts; remodel bone as needed
Why is bone resorption important?
For regulation of blood Ca levels and for releasing Ca stores necessary for bone remodeling
What do Haversian canals contain?
Small blood vessels and nerve fibers that serve the osteon’s cells.
What canals lie at right angles to the long axis of the bone and connect the blood and nerve supply of the medullary cavity to the central canals?
Volkmann’s (perforating) canals
________ lamellae lie between intact osteons. They are incomplete and either fill the gaps between forming osteons or are remnants of osteons that have been cut by bone remodeling.
Interstitial
________ lamellae are located just deep to the periosteum and just superficial to the endosteum. They extend around the entire circumference of the diaphysis and resist twisting.
Circumferential
What is the composition of bone extracellular matrix?
25% water, 25% collagen fibers, 50% crystallized mineral salts (calcium phosphate)
What is calcification?
The process of accumulating calcium ions
What is ossification?
Calcification that is initiated by osteoblasts; mineral salts are deposited and crystallize in the framework formed by the collagen fibers of the ECM
Bone’s flexibility depends on __________ _______.
Collagen fibers
What are sacrificial bonds?
Bonds between collagen fibers that stretch and easily break during stress, dissipating energy enough to prevent fractures in the bone