Specialised Connective Tissue 1: Bones Flashcards
What are the types of specialized connective tissue?
Bone and cartilage
What are the features of bone?
One of the hardest substances in the body
It is a living tissue composed of cells, fibers and extracellular matrix
Hard, calcified matrix (mineralized) with collagen fibers are found in bone
The calcium salts are deposited in the ground substance
Osteocytes are found in lacunae and are well vascularized
Gross anatomy of the bone
Diaphysis (long segment of bone)
Epiphysis (ends of the bone)
Membrane - Periosteum (on the outside of the bone) and endosteum (on the walls of the medullary canal)
Overall structure of compact bones
Compact bones are formed from osteons and osteocytes
What is the structural and functional unit of compact bones?
Osteon/Haversian system
Describe the structure of an osteon
Osteons are complexes of concentric lamellae of bone surrounding a canal containing blood vessels, nerves, and loose connective tissue
What are Perforating (Volkmann’s) Canal?
Canals lie at right angles to long axis of bone
What is the purpose of the Volkmann’s Canal?
Connect the vascular supply of the periosteum to the central canal and medullary cavity
What is the purpose of spongy/cancellous bone?
Spongy bone tissue is light and supports and protects the red bone marrow
Where can spongy bone be found?
Forms the structure of short, flat, and irregular bones, and the epiphyses of long bones
Structure of spongy bones
Consists of trabeculae surrounding many red marrow filled spaces
Does not contain osteons
What are the types of bone cells?
Osteoblasts
Osteocytes
Osteoclasts
What are osteoblasts?
Immature bone cells located on the bone forming surfaces
They are not yet embedded in the osteoid matrix
What is the purpose of osteoblasts?
Synthesize and secrete the osteoid matrix (uncalcified extracellular matrix)
Matrix is composed of glycoproteins & collagen
How are osteoblasts connected?
Cytoplasmic processes connect them with neighboring osteoblasts and nearby osteocytes
What are osteocytes?
Mature bone cells (osteoblasts that have become embedded in calcified bone matrix)
Where do osteocytes reside?
They reside in lacunae within the matrix
How are osteocytes connected?
Connected via canaliculi
What are osteoclasts?
Large multinucleated cells
What are the functions of osteoclasts?
Resorb bone during bone formation and healing, remodeling throughout life
Help maintain calcium balance in the body
