Flashcards in Specialized Connective Tissue; Bone Deck (15):
Which cartilage lacks a perichondrium?
What cells synthesize extracellular matrix?
Chondroblasts and chondrocytes
What is the composition of the extracellular matrix of cartilage?
Glycoproteins (in small amounts)
True or false: cartilage is vascular.
False; it's avascular
What 2 major factors maintain the firmness and flexibility of cartilage?
1. Electrostatic bonds between collagen fibers and glycosaminoglycan side chains of proteoglycans
2. Binding of water to glycosaminoglycans
If cartilage is avascular, then how does it receive nutrients and oxygen if
a) it's involved in joints
b) it's not involved in joints
a) Via diffusion from adjacent capillaries and synovial fluid
b) Via diffusion; the perichondrium contains blood vessels and lymphatics
From which embryonic germ layer is cartilage derived?
What are the 4 main areas of a long bone?
How do osteocytes communicate with each other?
Via processes that pass through canaliculi
What is the microscopic difference between osteocytes and osteoblasts?
Osteoblasts contain more ER and greater basophilic staining than osteocytes
What is osteomalacia?
State the difference between osteomalacia and rickets?
Osteomalacia is calcium deficiency in adults, while rickets is calcium deficiency in children. Hence, rickets affects how bones grow whereas osteomalacia affects already-formed bones.
State the steps of intramembranous ossification.
1. group of mesenchymal cells differentiate into osteoblasts
2. osteoblasts produce bone matrix
3. bone matrix undergo calcification, forming 'bone' islands
4. these bone islands/primary ossification centers form cavities that fuse
NOTE; the part of the mesenchme that doesn't get ossified gives rise to endostium and periostium
Causes of osteomalacia/rickets include...
1. Vitamin D deficiency
2. calcium deficiency
3. excess production of parathyroid hormone which increases resorption activity of osteoclasts