Bone Flashcards
______________________ is the main component of the adult skeleton
Bone
What are some functions of bone?
Support
Movement
Protection
Homeostasis
Bone is a type of what tissue?
Connective
There are two main components to bone. What are they?
ECM
Cells
The extracellular matrix of bone is _________________
Calcified
There are three types of bone cells. What are they?
Osteocytes
Osteoblasts
Osteoclasts
Calcified bone matrix prevents the diffusion of metabolits, so specialized exchange spaces _____________________ allow for nutrient exchange between osteocytes and blood capillaries
Canaliculi
All bones are lined on internal and external surface by layers of CT containing ________________ cells
Osteogenic
The _____________________ is internal and surrounds the marrow cavity
Endosteum
The ___________________ is external
Periosteum
The ________________ and ______________ are types of connective tissues that layer the surface of bones
Endosteum
Periosteum
__________________ are found in lacunae between bone
matrix layers (lamella) and have cytoplasmic processes in small canaliculi that extend into the matrix
Osteocytes
______________________ are growing cells that synthesize and secrete organic components of bone matrix
Osteoblasts
____________________ are giant multi-nucleated cells involved in removing calcified bone matrix and bone remodeling
Osteoclasts
_______________________ originate from mesenchymal stem cells and when active are located at the surface of bone matrix
Osteoblasts
Active osteoblasts are found at the surface of the bone matrix, bound by _____________________, where they form a single layer of __________________ cells joined by adherent and gap junctions
Integrins
Cuboidal
Some inactive osteoblasts differentiate into ____________________ as they are entrapped in the matrix-bound lacunae while others flatten and cover the matrix as ________________________; the majority, however, undergo apoptosis
Osteocytes
Bone-lining cells
______________________ produce the organic components of the bone matrix and therefore contribute to appositional growth
Osteoblasts
Osteoblasts secrete type __ collagen, proteoglycans, and matricellular glycoproteins, like _____________________
Type I collagen
Osteonectin
___________________________ is a layer of unique collagen-rich material between the osteoblast layer and pre-existing bone surface
Osteoid
Some osteoblasts become surrounded by the material they secrete and differentiate as __________________ enclosed singly in _______________
Osteocytes
Lacunae
What’s the function of osteocytes?
Maintenance of the bony matrix
Upon death they are resorbed into the matrix
In the transition from osteoblasts to osteocytes, the cells extend many long _____________________________ surrounded by calcifying matrix
Cytoplasmic processes
An osteocyte and its processes occupy each _______________ and the ____________________ radiating from it
Lacuna
Canaliculi