Flashcards in Connective Tissue II Deck (10):
Fx. of bone and cartilage?
1.) Protection of critical organs
2.) Mechanical support for locomotion
3.) Ca and phosphate homeostasis (bone is a Ca reservoir)
4.) To house, protect, regulate stem cell precursors of blood cells (hematopoietic system)
Calcium and phosphate crystals
dynamic, vascularized, constantly turned over/remodeled. Has a population of precursor cells that can divide/differentiate into new bone cells. Required to adjust blood ca and phosphate levels, to allow damage repair, to allow changes in structure in response to stimuli.
less dynamic. Avascular (diffusion nec). Limited in repair ability.
Can still be converted to bone in adults.
In adulthood it's in articular surfaces of bones and nose, ear, trachea etc.
Cartilage main fx
Provide resilient/pliable support structure
Direct formation/growth of bone
Make cartilage matrix and tissue. Can arise from mesenchymal cells or from external layer of connective tissue around the cartilage (perichondrium).
They secrete ECM components around themselves, become isolated into compartments called lacuna.
Proliferative chondrocytes = chondroblasts.
After growth they remove from cell cycle, but retain ability to secrete cartilage matrix at low rate
3 types of cartilage
distinguished by matrix:
contains collagen that forms thin fibrils, irregular 3D pattern. Ground susbtance is rich in proteoglycans and hyaluronic acid (hydration and flexibility). Hyaline:
-allows metabolites to readily diffuse tissue
-resiliency to compression during joint movement
-growth of chondrocytes and matrix from w/in the matrix
-During growth can calcify and attract cells that initiate bone formation
Contains thin collagen fibrils and proteoglycans too. But is distinguished by abundant elastic fibers/ interconnecting sheets (lamellae) of elastic material.
External ear, epiglottis, larynx.
Designed for elasticity, flexibility.